Reports / Archives / Research Reports / 2009/2010 / 2009 Projects Completed

Research Report 2009/2010

6.

 

Projects completed successfully or in which significant progress was made (Annexures I and II)


Index of projects

  1. Project titles

    1. Evaluation of advanced soybean breeding lines
    2. Evaluation of PRF-soybean elite lines under South African conditions
    3. National soybean cultivar trials
    4. Increasing soybean production on the Highveld
    5. Effect of SO2 and the interaction on growth, phy­siology and biochemistry of soybean (Glycine max) and canola (brassica napus), studied in an OTC system
    6. Phenotypic markers for nodulation capacity of soy­bean cultivars
    7. Establishment of an early warning system for soy­bean rust
    8. Determining the epidemiological value of resistance to rust caused by Pha­kopsora Pachyrhizi in soybean lines
    9. The use of silicon to control soybean rust (Pha­kopsora Pachyrhizi) and other related studies
    10. Generating management orientated maps for long-term soybean rust susceptible areas in South Africa
    11. Study of inoculation and disease evaluation tech­niques for Sclerotinia stem rot of soybean
    12. Control of Rhizoctonia Solani and Pythium spp. on soybeans (Glycine max), lupins (lupinus spp.) and canola using trichoderma and silicon
    13. Supersoya competition, KwaZulu-Natal
    14. Cultivar evaluation of oil and protein seeds in the winter rainfall area
    15. Assessing canola seed losses during seed ripening and harvesting in the Western Cape Province
    16. N-Fertilization of canola based on N-mineralisation and N leaching
    17. S-Fertilizer requirements of canola produced in the production areas of the Western Cape
    18. Optimal soil tillage methods and N-fertilizer rates to be used in a wheat / canola / wheat lupin and wheat monoculture crop rotation system in the Swartland production area
    19. Management of herbicide resistance in the Western Cape
    20. An investigation into the production dynamics of eight crop rotation systems, including wheat, canola, lupins and pasture species in the Swartland, Western Cape
    21. Economic sustainability of short- and long-rotation crop / pasture production systems in the Southern Cape
    22. The identification of soil parameters as indicators of sustainable dry-land crop production systems for the shale derived soils of the Western Cape: tillage practice, crop rotation, soil quality and crop pro­duction
    23. A: Enhancement of canola as a rotation crop within a conservation system in the dry land areas of the Swartland using a competition between producers
    24. B: Enhancement of canola as a rotation crop within a conservation system in the dry land areas of the Southern Cape using a competition between canola producers
    25. Insect and other pests of canola
    26. Characterization and management of Rhizoctonia on canola and lupin in cropping systems in the Western Cape Province
    27. The effect of raw full fat soybeans versus heat-treated full fat soybeans on the feed intake, feed efficiency ratio and growth rate of finishing ostriches
    28. Development of a simulation model to optimise the feeding of broiler breeder hens during lay
    29. Amino acid and protein utilization of broiler breeder hens fed maize-soya diets
    30. Questionnaire relating to canola production
    31. Income and cost budgets
    32. PRF website

6.1

 

Evaluation of advanced soybean breeding lines


EN Ndou and TA Masiha

Production of soybeans [Glycine max (L.) Merr.] in South Africa is relatively low and there are many factors that limit production of soybeans in South Africa, for example adaptability to local conditions. The aim of this breeding project was to evaluate genotypes that were developed from the previous programme and to release the best cultivars with improved adaptation and high yields. Twenty-five genotypes from the previous breeding programme and five local check cultivars were evaluated at Bethlehem, Brits, Potchefstroom and Vaalharts during 2008/09 season. The average number of days to 50% flowering across the locations varied between 54 to 68 days, with a mean of 63 days and there was no significant difference among the genotypes. However, there was a significant difference between the checks and genotypes. The average number of days to physiological maturity across locations varied between 125 in to 136 days. The mean number of days of physiological maturity across genotypes did not differ statistically. The number of days to harvest averaged at 153 days across locations. Genotype GP20-2-22-5 has attained the highest grain yield of 2 056.93 kg ha-1 and genotype TXS99-5-52 was attained the lowest grain yield mean of 1 404.36 kg ha-1, the trial mean grain yield mean 1 761.17 kg ha-1. There was no significant difference across genotypes. Genotypes across locations were not consistent and genotype GP20-2-22-5 was not stable across locations. However, the genotype that was ranked second across location was stable in Potchefstroom, Brits and Vaalharts where it was ranked first, fifth and sixth, respectively. Genotype X environment interactions proved to play a significant role in the success of any breeding programmes for the development of genotypes adapted to a wild range of environments.


6.2

 

Evaluation of PRF-soybean elite lines under South African conditions


GP de Beer and WF van Wyk
Contractors, Protein Research Foundation

INTA – Genotypes
Twenty-five genotypes, which include maturity groups 4 to 7, were planted at six sites in two 75 cm rows of 5 metres long with 3 replications on 7/12/2009. Six (6) local cultivars from Pannar and Link Seed were included as controls.

VIÇOSA – Genotypes
Five genotypes were planted at three sites in two 75 cm rows of 5 metres long with 3 replications on 13/12/2009. Two (2) local cultivars from Pannar and Link Seed were included as controls.

EMBRAPA – Genotypes
Sixteen genotypes were planted at six sites in two 75 cm rows of 5 metres long with 3 replications on 11/01/2010. Four (4) local cultivars from Link Seed were included as controls.

Twenty (20) different measurements were taken at each of these genotypes before threshing and five (5) after threshing. It seems that there are some good lines amongst these genotypes.


6.3

 

National soybean cultivar trials


JL Erasmus, HSJ Vermeulen, NN Mogapi and TC Ramatlotlo
ARC-Grain Crops Institute

In the national cultivar trials a total of 18 cultivars were evaluated at selected localities across the soybean production areas of South Africa. An additional 10 cultivars were evaluated at 10 locations in phase-1 trials. Trials were planted at research stations where the necessary infrastructure exists in order to carry out a comprehensive agrometeorological study. Trial sites were also selected in areas where a need for information exists and where the maximum amount of data could be collected. A comprehensive data set was collected on phenological data such as days to flowering, physiological and crop maturity, maximum plant height and minimum pod clearance, lodging, shattering and green stem, relative disease or pest susceptibility, seed characteristics and yield, physical and chemical quality, and soil and weather data. All data from the trials were analysed to calculate yield reliability for cool, moderate and warm production areas. The 2008/09 cultivar evaluation report was approved for publication. Mean seed yield across localities was 2 820 kg ha-1 compared to 2 456 kg ha-1 for the 2007 and 1 717kg ha-1 for the 2006 seasons. The highest average mean yields were obtained at Cedara (4 428 kg ha-1), Greytown (4 347 kg ha-1) and Vaalharts (4 244 kg ha-1). Overall cultivar LS 678 (3 164 kg ha-1) yielded the highest and Ibis 2000 (2 379 kg ha-1) the lowest. The cultivar with the highest protein percentage was Ibis 2000 with 43.73% and the lowest was PAN 1454 R with 40.97%. Cultivars that exceeded 5 t ha-1 were LS 6164 R at Vaalharts and Empangeni PD1, PAN 1666 R, PAN 737 R and LS 678 at Greytown and PHB 96 B 01 at Cedara.


6.4

 

Increasing soybean production on the Highveld


WF van Wyk
Contractor, Protein Research Foundation

Fertilisation

Treatments: Three (3) levels of P (0, 20 and 40kg/ha) and three (3) levels of K (0, 50 and 100 kg/ha).

The trials were harvested and all data were taken but no statistical analyses have yet been done. Large differences occurred between the treatments, as expected.

Cultivation methods with different rotation systems

Treatments: Plough (soya, soya – soya, maize – maize, soya), No-till (soya, soya – soya, maize – maize, soya), and disc (soya, soya – soya, maize – maize, soya). In 2009/10 a maize monoculture treatment was added to all three cultivation methods.

The trials were harvested and all data have been collected but no statistical analysis has yet been done. The benefit of soybeans is already apparent on maize after soybeans.


6.5

 

Effect of SO2 and the interaction on growth, physiology and biochemistry of soybean (Glycine max) and canola (brassica napus), studied in an OTC system


JM Berner, S Lindeque, M Minnaar, PDR van Heerden and GHJ Kruger
School for Environmental Sciences, North-West University, Potchefstroom

Soya (PAN 1666 and LS 6164) plants were exposed to 25, 75 and 150 ppb of sulphur dioxide (SO2) in an OTC system. The activities of two stress associated enzymes, lipoxygenase (LOX) and peroxidase (POD) were determined. Lipoxygenase is a key enzyme in the lipoxygenase pathway leading to the production of oxylipins. Oxylipins are secondary metabolites that regulate stress responses and often participate directly in a stress response. Reactive oxygen species are formed during a stress response and needs to be quickly detoxified. Peroxidase is one of many antioxidant enzymes responsible for detoxifying free radicals. The activities of both LOX and POD increased as the levels of SO2 concentrations increased. A significant increase in these activities could be detected as early as 3 weeks after the start of fumigation. PAN 1666 had significant higher in­creases in LOX and POD activity Compared to LS 6164. These results suggest that PAN 1666 has a higher level of SO2 tolerance when compared to LS 6164.

Canola (Rainbow) was exposed to 50, 100 and 200 ppb of SO2. The effect of SO2 on the plants was followed by means of chlorophyll fluores­cence. The performance index (PIABS) is based on the fast phase chlorophyll fluorescence rise. It is a multi-parametric function taking into account all partial processes of primary photochemistry, namely absorption of light energy, trapping of excitation energy and conversion of excitation energy to electron transport. After 5 weeks of fumigation a decline in the PIABS was noticed as the levels of SO2 increased. The activity of antioxidant enzymes POD and ascorbate peroxidase (APX) was determined. A significant increase of POD was observed with the 50, 100 and 200 ppb SO2 treatments compared to the control. There were no significant differences in the POD and APX activities between the different treatments.


6.6

 

Phenotypic markers for nodulation capacity of soybean cultivars


BA Fenta¹, S Driscoll², C Foyer² and K Kunert¹
¹Plant Science Department, Forestry and Agricultural Biotechnology Institute, University of Pretoria, ²Centre for Plant Sciences, Faculty of Biology, University of Leeds UK

The sustainability of grain legume production is severely restricted by drought. To investigate the physiological basis of drought tolerance in soybean the genotypic variation in drought sensitivity was exploited with the aim of defining phenotypic markers that may assist future breeding programmes. Therefore, physiological parameters that characterise the response of soybean plants to drought were characterized and the responses of three soybean cultivars (Prima 2000, A5409RG and Jackson) to the onset and progression of drought imposed by water deprivation were compared using a range of shoot, root and nodule parameters. Results obtained show that the kinetics of soil water loss and drought-induced decline in leaf water potential values are similar in all three cultivars. Also stomatal conductance values declined rapidly following water deprivation in the three cultivars and photosynthesis was progressively inhibited in all three cultivars under drought conditions. However, Prima leaves retained higher photosynthetic CO2 assimilation rates than A5409RG or Jackson. This was even after 20 days of water deprivation. Further, exposure to drought altered the biomass partitioning between roots and shoots and shoot/root ratios declined significantly in all three cultivars. However, Prima roots and shoots had greater total biomass than those of Jackson or A-5409RG under both well-watered and drought conditions and further drought-treated A-5409RG plants retained the highest shoot to root ratios. Jackson plants had the lowest nodule number per root while A5409RG roots had the highest number. High symbiotic nitrogen fixation (SNF) rates were found only in a relatively narrow range of high leaf water potential values. Drought treatment decreased nodule numbers by about 90% and SNF declined to near zero values. Correlations between SNF and photosynthesis rates, and SNF and shoot fresh weight were further found. From the experiments, we conclude that while drought severely inhibits SNF in all three cultivars, Prima has a robust photosynthetic capacity that sustains more vigorous growth and higher rates of biomass accumulation despite severe limitations in soil water availability. Data have been submitted for publication in Journal of Experimental Botany.


6.7

 

Establishment of an early warning system for soybean rust


M Craven, GP de Beer¹, TM Ramusi and AS de Beer
ARC-Grain Crops Institute, ¹Protein Research Foundation

Due to the destructive nature of soybean rust and an apparent lack of adequate resistance to the disease an effective disease management sys­tem is required until resistant cultivars become available. Disease scouting in order to detect the pathogen as early as possible is an important key to an effective management programme. Since the 2005/06 season the ARC-Grain Crops Institute (ARC-GCI) together with the Protein Research Foundation (PRF) and other co-workers such as PANNAR, the department of agriculture of KwaZulu-Natal (KZN) and a number of soy­bean producers have attempted to create a soybean-rust-earlywarning system that is based on trap-crop trials, also referred to as indicator plots. Data generated during this study contributed to the confirmation of a general seasonal trend of soybean rust movement from east to west in al soybean production areas in South Africa. A screening protocol was also established that will be used for the monitoring of soybean rust develop­ment in future.

This past season rust was first detected at Dirkiesdorp, Vryheid and Cedara (15 January 2010) followed by Greytown (28 January 2010), Norman­dien and Morgenzon (8 February 2010), Greylingstad (16 February 2010), Kinross and Kestell (16 March 2010) and finally at Potchefstroom (23 March 2010).


6.8

 

Determining the epidemiological value of resistance to rust caused by Phakopsora Pachyrhizi in soybean lines


NW McLaren and C Botha
University of the Free State

Soybean cultivars and alternative lines were evaluated in the field (Cedara) for soybean rust resistance. Three planting dates were used spaced approximately two weeks apart. Plants were dependent on natural infection. Subsequent to when infection was first noted, plants were scored using the criteria of the percentage infection and percentage defoliation and the two criteria were pooled to determine the total affected leaf area. Lines (PI 603909A and PI 606376 had overall the lowest rust severity ratings (mean = 2.5%) while PI 567616 and PI 603166 had higher defoliation percentages and rust severities than the other germplasm evaluated. These genotypes have been planted in the greenhouse to corroborate data.

A short, medium and long season variety i.e. PAN 1545RR, SNK 500 and LS 678 respectively, were planted over five selected planting dates at Cedara to determine the relationship between host physiology and disease susceptibility. Mean rust severity ratings ranged from 5% in SNK 500 to 25% in PAN 1454 RR. However, PAN 1454 RR is a short season variety and tended to escape the effects of the disease more readily than SNK 500 and LS 678.

An aim of this study is to identify physiological markers associated with variations in the response of soybeans to the rust pathogen, notably those associated with delayed disease onset and reduced rate of disease development. Leaves were sampled at R3 growth stage to extract intercellular wash fluids. Leaves were washed and dried and placed in a vacuum tube with sodium acetate buffer (pH 5.2) and vacuumed for 5 minutes. Leaves were then dried and paced in centrifuge tubes. These were centrifuged at 2000rpm for 10 min at 4ºC. The intercellular fluids were placed in Eppen­dorf tubes and placed in the freezer until further use. These fluids as well as sampled leaves will be used for the determination of PR proteins (β-1,3-glucanase, peroxidase and chitinase), enzymes (PAL, peroxidase), total and specific phenols and total carbohydrates. Analyses of these compounds are currently being conducted.

Blocks of SNK 500 (susceptible) were planted and different levels of Urea and LAN were applied to the soil. Noticeable differences in the time of disease onset and final rust severity ratings was recorded between treated and control plots. Higher ratings were observed in plots with low fertilizer concentrations and control plots. Control plots with no fertilizer added and an absence of rhizobium showed higher disease severity ratings and a faster rate of defoliation indicating that host vigour and extended periods of cellular activity plays a role in delaying disease onset and rate development. N-treated plots are also being used as a source of variation in determining the role of proteins, enzymes, phenols and carbohydrate concentration in relation to rust development as well as variation in photosynthetic activity (chloroplast fluorescence) compared to the control plots with no amendments.


6.9

 

The use of silicon to control soybean rust (Phakopsora Pachyrhizi) and other related studies


D Visser and P Caldwell
University of KwaZulu-Natal

Effect of root application of potassium silicate to control soybean rust

Aim: To determine the effect of root application of silicon on the control of soybean rust.

Materials and Methods: For pot trials, soybean seed (LS 6161) will be planted in pots and placed in a glasshouse. Si (0, 100, 500, 1000, 1500 and 2000mg/liter) will be applied by drenching pots for 4 weeks. pH and KCl controls will be included. Plants will be artificially inoculated and placed in the dew chamber for 24 hours. Thereafter plants will be placed in a Conviron and rated for number of pustules per lesion and lesion size 21 days post inoculation.

For field trials soybean seed (LS 6161) were planted at Cedara (2009/2010) in 3 x 1.75m plots. The treatments were as follows: uninoculated control, Punch C, Punch C and 2000 mg/liter, half strength Punch C and 2000 mg/liter, half strength Punch C, 1000 mg/liter, 2000 mg/liter (2 applications), and 3 slow release silicon fertilizers at 3 rates each. Soil samples were taken before Si was applied and after the last Si application and analysed for Si concentration. Plants were rated for percentage disease and the AUDPC calculated. Yield was also determined.

An accelerated ageing test on the seed from the field will also be conducted. 36 seed from each treatment will be removed and tested according to the International Seed Testing Association (ISTA), to determine whether the use of root applied silicon will increase the storage life of soybean seed.

Status: Pot trials are still to be conducted during November/December 2010 (over the summer season). Field trials in the 2007/2008 season have been conducted at Baynesfield and analysed. The trial has since been amended and completed (2008/2009 season) at Cedara. Further amendments have been made and the trial completed (2009/2010 season) at Cedara. The AUDPC's have been calculated, and the trial has been harvested and the yield is currently being determined for the 2009/2010 season. The trial will be repeated in the following season (2010/2011) at Cedara. Special accelerated aging equipment is currently being built for seed testing. This test should be conducted within the next month.

The effect of foliar application of potassium silicate on the control of soybean rust

Aim: To determine the effect of foliar application of potassium silicate on the control of soybean rust.

Materials and Methods: For glasshouse trials, soybean seed (LS 6161) will be planted in pots and placed in a glasshouse. Potassium silicate (0, 250, 1000 and 2000mg/liter) was applied using a hand sprayer until runoff at the V4 growth stage. A pH and KCl control were included, as well as a Punch C control, and two slow release silicon fertilisers. 24 hours after silicon application, plants were inoculated with uredospores and placed in the dew chamber for 24 hrs. Plants were then moved to a Conviron for the remainder of the trial. Plants will be rated for number of pustules per lesion and lesion size 21 days post inoculation.

For field trials, soybean seed (LS 6161) was planted at Cedara (2009/2010) in 3 x 1.75m plots. Plants were sprayed till runoff with silicon at 0, 1000, 2000 and 4000mg/liter. A drench of 1000mg/liter and a Punch C control were also included. Treatments were applied at the V6, R1 and R4 growth stages. Soil samples were taken before Si was applied and after last Si application and will be analysed for Si concentration. Plants were rated for percentage disease and the AUDPC calculated. Yield was also determined.

An accelerated ageing test on the seed from the field will also be conducted. 36 seed from each treatment will be removed and tested according to the International Seed Testing Association (ISTA), to determine whether the use of foliar applied silicon will increase the storage life of soybean seed.

Status: A field trial has been conducted in the 2009/2010 season at Cedara. The trial has been harvested and the yield is currently being determined. The trial will be repeated in the following season (2010/2011) at Cedara. An initial greenhouse trial has been conducted, and plants will be rated in the middle of June, and a further trial will be conducted once the results from the initial trial have been obtained. Special accelerated aging equipment is currently being built for seed testing. This test should be conducted within the next month.

Uptake and distribution of silicon in soybeans

Aim: To determine the level and distribution of deposited and soluble silicon in the different parts of the soybean plant using a hydroponics and drench setup.

Materials and Methods: For deposited silicon, soybean seed (LS 6161) were grown in hydroponics (ideal conditions) and glasshouse (drench – field conditions). Silicon was applied for 6 weeks (0, 50, 100, 150, 200, 250, 300, 400 and 500 mg/liter and 0, 50, 100, 250, 500, 1000, 1500 and 2000mg/liter respectively. Plants were harvested under four different categories: root, stem, young leaves and old leaves, and digested using the Microwave Accelerated Reaction System (MARS). Samples were then analysed using the Inductively Coupled Plasma Optical Emission Spectrophotometer (ICP-OES) for silicon, calcium, potassium, phosphorus and manganese. For soluble silicon, the trial was run as above, but plant leaves were harvested, and 1g of fresh crushed leaf tissue ultrasonified (to disrupt cells) in 10ml water, and left to shake overnight at 4ºC. Samples were then centrifuged twice, and the supernatant removed and analysed using ICP-OES (as above).

Status: Due to problems with the torch on the ICP, analyses still has to be conducted with a new specialized torch that has been purchased. This will take place in the winter months of 2010. Electron microscopy/EDX is still to be conducted. The soluble silicon trial has been conducted, and will be analysed in the next few months.

The economics of the use of silicon to control soybean rust

Still to be determined.

The physiological effects of silicon on soybeans subjected to cold stress

Still to be done.


6.10

 

Generating management orientated maps for long-term soybean rust susceptible areas in South Africa


L van Niekerk and P Caldwell
University of KwaZulu-Natal

The aims of the study are 1) to study the effect of plant density on the suppression of weeds (biomass) by different canola cultivars in the Swartland and Southern Cape and 2) to study the effect of plant density on the development (flowering date, physiological ripening date), growth (biomass of reproductive versus vegetative components), plant length, yield and quality of different canola cultivars in the Swartland and Southern Cape canola production areas. Field trials were planted on the Roodebloem experimental farm (Southern Cape) and the Langgewens experimental farm (Swartland) respectively. In one set of experiments at each locality the recommended weed control programs were followed to create a weedfree environment. In the second set of experiments no weed control (except for nonselective herbicides before planting) were carried out to determine the weed suppressive effects of the different canola cultivars. The treatments were as follows: a) 4 cultivars (1 open pollinated and 1 hybrid cultivars each of the TT and Clearfield types) (CB Jardee, Bravo, 43c80 and 45y82) were planted and b) sowing densities were manipulated with the aim of achieving 4 plant densities (30, 60, 90 and 120 plants m-2). Plant samples (canola and weeds) were taken about 60 and 90 days after establishment and the dry mass was determined. Yield and physiological ripening date of the canola seed were determined as well as crude protein and crude fat content. Preliminary results showed, as expected, that the weed infested trials had a much lower plant density as well as biomass production of canola plants. There are however, no clear trends in terms of the effect of cultivar or plant density on weed suppression or yield. There are however still results that need to be statistically analyzed and these results may clarify the picture. The research will be continued in 2013 and 2014.


6.11

 

Study of inoculation and disease evaluation techniques for Sclerotinia stem rot of soybean


NW McLaren and C Botha
University of the Free State

In 2008/2009 soybean cultivars and lines were planted in Greytown at Pannar for field evaluation of resistance to Sclerotinia stem rot. No disease was observed. These cultivars and alternate sources of germplasm were therefore evaluated in the greenhouse. Plants were grown to V3 growth stage and inoculated using the spray mycelium method. A plastic tent was placed over the inoculated plants to maintain a high RH and to promote infection. After 6 days the tent was removed and disease was scored using a rating scale for leaf damage and wilting severity. Means for leaf damage rating ranged from 2.6 to 4.3 on a 0-5 rating scale, with Dundee the most susceptible of the cultivars evaluated. Cultivars PAN 1583 R, PAN 1652 and LS 6162 R showed various levels of resistance to the disease. Similarly, wilting severity means range from 36.6 to 86.6% and PAN 1652, PAN 1583 R and LS 6162 R had the lowest wilting severity. LEX 2257 R had the highest wilting severity of 86.6% followed by Dundee with 83.3%.

During the 2009/2010 season, soybean lines and commercial cultivars were again planted in field trials at Pannar in Greytown for Sclerotinia stem rot evaluation. Four planting dates were used, spaced approximately two weeks apart to ensure environmental diversity during the critical suscep­tible stage of plant development. At flowering plants were inoculated using a colonized sorghum grain method. Plants were scored approximately 4 weeks after inoculation for disease incidence. These evaluations indicated that PHB 96 B01, PHB 95 B 53 and LEX 1235 R had highest disease incidence during the first planting. During the second planting, PHB 96 B 01, PHB 96 B 53, LEX 1235 R and IBIS 2000 showed greatest disease incidence. Data will be used to determine disease potential x observed incidence response graphs for risk analyses. These cultivars will also be planted in the greenhouse to corroborate data.

Field data also served to add to a weather database being developed with the aim of defining more precisely those conditions that favour disease development and the development of a risk analysis model.

Pathogenicity tests with S. sclerotiorum isolates were conducted on two soybean cultivars in the greenhouse, i.e. SNK 500, a susceptible cultivar and Egret a moderately resistant cultivar. Plants were inoculated using the spray mycelium method, covered to ensure high humidity and nine days after inoculation bags were removed. The severity of leaf damage, degree of wilting and the number of dead plants were recorded daily using a 0-5 and percentage rating scale. Analyses of variance revealed that the isolates of S. sclerotiorum significantly affected the severity of leaf damage on the two cultivars evaluated. Mean values ranged from 2.5 to 4.0 and isolate 7 (Kinross) produced the highest leaf damage rating. When wilting incidence was evaluated a significant difference was observed between the 18 different isolates evaluated. A significant host x pathogen inter­action was also recorded indicating that isolates may be at least partially adapted to specific host genotypes. Isolate 7 once again resulted in the highest degree of wilting (mean = 80.0%) compared to isolate 15 with a mean of 30.0%.

A modified method of an oxalic acid assay by Tu (1989) was conducted on the two soybean cultivars to determine whether oxalic acid tolerance could be correlated with host response to S. sclerotiorum. Oxalic acid is associated with pathogenesis. Primary leaves were excised and the peti­oles were immediately submerged in a Petri dish containing water. Each leaf was subsequently assigned to a vial with the specific test concen­tration of oxalic acid and the leaf was maintained at room temperature for 72 h. The percentage of leaf area with brown rot symptoms were assessed daily for 3 days. Eight concentrations were evaluated ranging from 0.5 mM to 80 mM. At 0.5 mM, no significant differences between the two cultivars were observed. When the concentrations increased however, SNK 500 showed more browning and necrosis than Egret. At 40 mM oxalic acid, SNK 500 had an average of 61.8% browning at day 1, 71.5% at day 2 and 78.1% at day 3. When compared with Egret, 37.5% browning was observed at day 1, 49.0 at day 2 and 58.1% at day 3. This indicated that oxalic acid plays a primary role in Sclerotinia stem rot development, especially when the disease is present in a susceptible cultivar.


6.12

 

Control of Rhizoctonia Solani and Pythium spp. on soybeans (Glycine max), lupins (lupinus spp.) and canola using trichoderma and silicon


R Bosse, S Jadoo, P Mzimela and P Caldwell
Discipline of Plant Pathology, School of Agricultural Science and Agribusiness, University of KwaZulu-Natal

Rhizoctonia solani and Pythium spp. are the causal organisms of seed and seedling diseases of many crops. They are known as sub-lethal patho­gens causing reduced germination and yield. Silicon (Si) has been shown to act as a component in plant resistance against abiotic and biotic stresses. Resistance to pathogens is associated with a high deposit of Si in the leaf where it forms a mechanical barrier on the epidermal cells, impeding pathogen penetration. Silicon has also been shown to activate host defence responses.

The aim of this trial was to investigate the growth promotion activities of Si, applied in the form of potassium silicate, and Trichoderma (Eco-T®) on soybeans, lupins and canola. The control of R. solani and Pythium was also investigated. Inoculated barley seeds were used in the pathogen control trial but no pathogens were used in the growth promotion trial. Five treatments were investigated, i.e., 200 mgl-1 Si plus KOH (to balance the potassium ions in the potassium silicate), Eco-T®, 200 mgl-1 Si plus Eco-T®, a control and KOH (as a control to investigate the possible pH effects of the potassium silicate). Pot trials were used to measure the shoot biomass of the plants, while rhizotrons were used to measure root area, root biomass and root length.

Results showed that the combination of 200 mgl-1 Si plus Eco-T® gave the best results for all crops investigated. Growth promotion studies showed that the application of 200 mgl-1 Si and Eco-T® resulted in a significant increase in shoot biomass (22.45 g), root area (14.66 cm²), root biomass (0.22 g) and root length (143.25 cm) compared to the control (14.64g, 7.32 cm², 0.15g and 105.17 cm), respectively. Similar results were found in the Pythium control trials where the application of 200 mgl-1 Si and Eco-T® also showed a significant increase in shoot biomass (19.74 g), root area (9.77 cm²), root biomass (0.093 g) and root length (140.93 cm) compared to the inoculated control (9.09 g, 5.74 cm², 0.047 g and 81.75 cm), respectively. For the Rhizoctonia control trials this pattern was repeated with similar results as application of 200 mgl-1 Si and Eco-T® also showed a significant increase in shoot biomass (20.45 g), root area (8.98 cm²), root biomass (0.094 g) and root length (131.2 cm) compared to the control (7.45 g, 5.05 cm², 0.032 g and 65.89 cm), respectively. It appears that Eco-T® protects the seed against Rhizoctonia and Pythium before root development, but once roots develop, the Si taken up by the plant prevents pathogens penetrating the root area.

Lupins and canola showed similar results where applications of 200 mgl-1 Si and Eco-T® resulted in the greatest increase in root and shoot biomass, root length and root area and the best control of R. solani and Pythium, compared to the control.


6.13

 

Supersoya competition, KwaZulu-Natal


C Havenga
Contractor, Protein Research Foundation

The Super Soya Competition in KwaZulu-Natal is now in its twentieth year and interest and support are still on the increase. This season it was decided to join the Northern and Southern competitions again as one combined competition. The Bergville-Winterton area had the biggest number of entries with 26, followed by Newcastle-Dundee with 17 and Vryheid-Paulpietersburg with 14 entries.

The most important aspect of this competition is the opportunity which it creates to exchange knowledge and experience of different production practices and to evaluate them according to the results obtained. Here farmers, scientist and advisors have the opportunity to exchange ideas, knowledge and experience.

Yields in the past season's Super Soya competition varied between 1.83 and 5.75 tons/ha. The average yield was 3.32 tons/ha which is consider­ably better than the previous season's 2.8 tons/ha. The average irrigation yield was 3.6 tons/ha which is only slightly higher than the average dryland yield of 3.23 tons/ha. The highest yield obtained from a dry land field was 5.75 tons/ha was.

In general the protein content of the soybeans was satisfactory to very good, ranging from 35.5 to 40% (dry matter basis) with an average content of 39%, which is slightly lower than the previous season's 39.9%. Only one land yielded a crop with a protein content of less than 37% (DM basis). The long term average protein contents of the Super Soya entrants is shown in Table 1, where it can be seen that since 1997 the average protein content exceeded the acceptable minimum protein content of 37%.

Oil content ranged from 16.4 to 21.2% on a dry matter basis. The average oil content this past season was 19.1% which is slightly lower than the previous season (Table 1).

A summary of the average yields, protein and oil content and break-even yields since the start of the Super Soya Competition is given in Table 1.

Table 1
Historical yield, protein content data
Season Average yield
(tons/ha)
Average protein
%
Break-even yield
(tons/ha)
Number of entries
1989/90 1.69   1.14 12
1990/91 2.35 35.8 1.13 21
1991/92 2.10 38.3 0.99 18
1992/93 2.12 35.3 1.09 23
1993/94 2.92 38.9 1.18 26
1994/95 2.52 35.7 1.29 25
1995/96 2.31 36.9 1.32 33
1996/97 3.01 38.7 1.04 42
1997/98 3.23 38.8 1.54 47
1998/99 2.69 39.5 1.69 42
1999/00 2.93 42.8 1.45 31
2000/01 2.89 40.1 1.43 43
2001/02 3.01 41.2 1.08 38
2002/03 3.03 40.7 1.84 29
2003/04 3.38 41.9 1.54 24
2004/05 3.18 40.6 1.84 31
2005/06 3.71 41.9 1.15 46
2006/07 2.75 39.1 0.98 46
2007/08 3.17 39.9 0.82 50
2008/09 3.32 39.0 1.55 57

The average pre-harvest production cost of participants almost doubled and increased by R1996 /ha from the previous season's figure. The break-even yield of 1.55 ton/ha is the highest during the past 4 seasons (Table1).

Participants entered twenty (20) different cultivars and 91% of these were Roundup Ready cultivars.

During recent years more and more farmers moved away from the use of mould board and disc ploughs towards chisel ploughs and disc harrows. Minimum tillage and No-till is becoming a more popular way of growing soybeans and was practiced this past season by 69% of the participants. One participant ploughs his fields with a mould board plough and the rest of the participants (28%) cultivate their fields with a chisel plough or disc harrow.

This competition creates an opportunity to record and evaluate the results of production practices thereby identifying production problems which then may lead to research projects to solve these problems.


6.14

 

Cultivar evaluation of oil and protein seeds in the winter rainfall area


PJA Lombard
Institute for Plant Production, Department of Agriculture: Western Cape

During 2009 the climatic conditions were favourable for crop production in the Swartland. However the yield was not as good as expected. Dry weather and strong winds occurred during harvest time which resulted in seed losses. The climatic conditions in the Southern Cape were even less favourable; four trials were written off due to bad and uneven germination.

The Department of Agriculture Western Cape planted 14 canola cultivar trials in 2009. The average trial yield in the Swartland was less than in 2008 (1.664 ton/ha compared to 2.45 ton/ha in 2008). The yield varied between 1.46 ton/ha (Langgewens 2) and 1.938 kg/ha at Malmesbury. The conventional cultivar Garnet was the top producer in the Swartland (2.148 ton/ha). The yield of 3 hybrid cultivars did not differ significantly from Garnet. The three cultivars were 44Y06, AGA Max and the "Clearfield" hybrid cultivar 45Y77. The Triumph Jardee TT (1.737 ton/ha) (hybrid TT cultivar) was the top producing TT cultivar in the Swartland. The yield of Garnet was not significantly better than Thunder TT, Bravo TT or Triumph Jardee TT.

The average trial yield in the Southern Cape varied between 1.571 ton/ha at Klipdale to 1.954 ton/ha at Tygerhoek 1. The conventional cultivar Garnet was the top producer in the Southern Cape (1.571 ton/ha). The yield of 3 hi-bred cultivars, AGA Max, Hyola 61 and the "Clearfield" cultivar 45Y77, did not differ significantly from Garnet. The top producing TT cultivar was Thunder. However the yield of Thunder did not differ significantly from Triumph Jardee TT, ATR Cobbler or Tornado TT.


6.15

 

Assessing canola seed losses during seed ripening and harvesting in the Western Cape Province


JA Strauss
Institute of Plant Production, Department of Agriculture: Western Cape

Many producers have observed considerable crop losses in canola due to a combination of natural shedding (including as a result of inclement weather conditions during ripening) and losses during harvesting. Potential yields as indicated from numerous cultivar evaluation trials are seldom achieved. Field observations during 2009 have indicated losses of 722 kg/ha on average. At the current price of canola, a loss of 722 kg of seed could mean a potential income loss of more than R2093/ha. Avoidable seed losses currently exacerbate the perception that canola production is less profitable than wheat production. This study comprises a replicated field trial that included two harvesting techniques (swathing and direct harvesting), and the use of an anti-pod shatter agent in a completely randomized blocks design; and a survey of seed losses on farms where both harvesting methods are used. The second year of the survey of the commercial farms showed losses of 33% and 37% for the two methods respectively. Losses of 28% (directly harvested) and 12% (swathed) were recorded in the statistical trial. The bulk of these losses occurred during the harvesting process. In the past season the effect on strong winds during the ripening stage was also shown clearly in the statistical trial, where up to 900 seeds per container were counted in the straight canola plots.


6.16

 

N-Fertilization of canola based on N-mineralisation and N leaching


GA Agenbag
Stellenbosch University

Research to evaluate the response of canola to increasing N application rates of 0 to 120 kg N ha-1 and methods of application (broadcasted compared to banded) was continued with field trails at Langgewens-, Elsenburg-, Welgevallen- and Roodebloem Experimental Farms during 2009. Unfortunately the experiment at Welgevallen had again to be abandoned due to very wet and flooded conditions. Soil analysis were done at all localities before planting, while plant analysis were done at Langgewens and Elsenburg at 90 days after planting on plots receiving either no nitrogen or 90 kg N ha-1.

At Elsenburg sub-optimal soil pH (<5.0 pHKCl) values were recorded, while all localities recorded low soil S (<6.0 mg kg-1) contents. Because superphosphate (12% S) was used as source of P fertilizer, approximately 15 kg S ha-1 was applied at all localities. In spite of this, plant analysis at 90 days after planting at Langgewens and Elsenburg showed suboptimal S contents (<0.5%). In comparison to general norms for Na (300-5000 mg kg-1) high plant Na contents were found at both localities with values as high as11 000 mg kg-1. In contrast to Elsenburg, plant Na-content at Langgewens increased with increasing N application rates. The soil carbon content (% C) varied between 0.35% at Langgewens; 0.63% at Elsen­burg and 1.51% at Roodebloem. N-mineralization during the period 0-40 days after planting in the 0-20 cm soil profile was calculated as 54.8 kg N ha-1 at Langgewens; 73.5 kg, N ha-1 at Elsenburg and 76.7 kg N ha-1 at Roodebloem. Although plant N-contents at 90 days after planting were higher with the 90 kg N ha-1 application rate, N-contents of plants receiving no fertilizer nitrogen were still adequate (higher than the norm of 0.35%).

Due to differences in rainfall and already discussed differences in N-mineralization potential of the soil, grain yield again differed largely between localities. At Langgewens where the nitrogen supplied by the soil during the period 0-40 days after planting was calculated as 54.8 kg N ha-1, a grain yield of 1182.9 kg ha-1 was produced without any N-fertilizer added. At Elsenburg and Roodebloem N-mineralization potentials of 73.5 kg, N ha-1 and 76.7 kg N ha-1 were calculated, while yields of 2130.0 and 1379.2 kg ha-1 were produced without any N-fertilizer added. In contrast to other localities only 1.0 m² from every plot was cut during the physiological mature stage, dried and thrashed under laboratory conditions to prevent bird damage and yield losses before harvesting at Elsenburg. These practices, together with better growing conditions and deeper soils may be the reasons for higher than expected yields at Elsenburg.

At all localities grain yields increased with increasing N-fertilizer rates and the highest yields of 1513.2 kg ha-1 at Langgewens, 1949.5 kg ha-1 at Roodebloem and 3155.2 kg ha-1 at Elsenburg were obtained with nitrogen application rates of 90-120 kg N ha-1. Agronomical efficiencies of N applications (kg yield increase per kg N applied) varied between 2.9 at Langgewens, 4.8 at Roodebloem and 8.5 at Elsenburg. Band placed N-fertilizer were more efficient compare to broadcasted applications and yields were between 3.0 and 8.4% higher with similar N-application rates. The best results at Langgewens and Roodebloem were obtained when N was applied not later than 60 days after planting, while yields at Elsen­burg were increased with a N application at 90 days after planting.


6.17

 

S-Fertilizer requirements of canola produced in the production areas of the Western Cape


GA Agenbag
Stellenbosch University

Experiments with three S application rates (0, 15 and 30 kg S ha-1) in combination with 5 N application rates (0, 30, 60, 90 and 120 kg N ha-1) were conducted during 2009 on four localities, but one (Welgevallen experimental station) was terminated due to very wet and flooded soil con­ditions. On the remaining localities the S-content of the soil varied between 2.2 mg kg-1 at Elsenburg, 2.8 mg kg-1 at Langgewens and 3.2 mg kg-1 at Roodebloem, which were all less than the required 6 mg kg-1 needed for the production of canola. Calculated N mineralization potential during the first forty days after planting ranged between 54.8 kg N ha-1 at Langgewens; 73.5 kg N ha-1 at Elsenburg and 76.7 kg N ha-1 at Roodebloem.

Grain yields increased on all localities with an increase in N application rate. At Langgewens, yields increased from 889.5 kg ha-1 where no nitro­gen was applied to 1439.0 kg ha-1 with an application rate of 120 kg N ha-1. At Roodebloem, yields increased from 1122.9 kg ha-1 with no nitro­gen applied to 2101.9 kg ha-1 with an application of 120 kg N ha-1, while yields at Elsenburg increased from 2260.0 kg ha-1 with no N application to 3682.6 kg ha-1 with 120 kg N ha-1. In contrast to other localities, only 1.0 m² was cut during the physiological mature stage, dried and thrash­ed under laboratory conditions to prevent bird damage and yield losses before harvesting at this locality. These practices together with better growing conditions and deeper soils may be the reasons for high yields at Elsenburg. No clear yield responses to S application rates were obtained. In general, yields tend to increase with higher S application rates and significant interactions between N and S, found at all localities', indicated better responses to S at high compare to low N application rates. Chemical leaf analysis at 90 days after planting, however showed S deficiencies (<0.5%) at all localities irrespective of S application rate. Higher S application rates and/or split applications should therefore be investigated.


6.18

 

Optimal soil tillage methods and N-fertilizer rates to be used in a wheat / canola / wheat lupin and wheat monoculture crop rotation system in the Swartland production area


GA Agenbag
Stellenbosch University

In this trial on Langgewens Experimental Farm, the effect of soil tillage methods on soil fertility and crop yields has been studied for the past 30 years and that of two crop rotation systems for more than 15 years. Different nitrogen application rates have been evaluated since 2000.

Both wheat and canola crops were grown during 2010, but yields were generally low due to very severe weed infestations. On average canola yields (1429 kg ha-1) were slightly higher than that of wheat (1331 kg ha-1) grown in monoculture, because of more efficient weed control with simazine used in the triazine tolerant canola crop. Canola responded better to increased nitrogen applications compared to wheat. On average, grain yield of canola increased from 864.7 kg ha-1 with an application of 20 kg N ha-1 to a yield of 1863.7 kg ha-1 with an application of 100 kg N ha-1. In the case of wheat, similar increases in nitrogen application rates resulted in yield increases from 1171.0 kg ha-1 on average to 1573.7 kg ha-1. Due to more efficient mechanical weed control and higher soil N-mineralization rates, conventional soil tillage systems, which include mould board ploughing, resulted in the highest yields of 2070 kg ha-1 (on average) when wheat was produced in monoculture. On average conventional tillage also resulted in the highest yield of 2157.7 kg ha-1 in canola. The highest canola yield of 2840 kg ha-1 was however obtained when 100 kg N ha-1 was applied in a system of minimum tillage (applying a shallow cultivation with a chisel plough before planting).


6.19

 

Management of herbicide resistance in the Western Cape


PJ Pieterse
Stellenbosch University

The main objectives of the project are to determine the level of herbicide resistance and the efficacy of other herbicides in weed samples sent in for testing as well as to investigate the effect of different cropping practices on ryegrass numbers in crop fields. During the 2009 season 24 weed samples were tested for herbicide resistance and it was found that four samples showed resistance to a single herbicide, six samples showed resistance to more than one herbicide from the same group (mode of action) whilst 14 samples showed resistance to herbicides from more than one group. It was shown beyond doubt that certain wild oat populations have resistance to glyphosate and resistance in Calomba daisy (Stink­kruid) to a mixture of MCPA and bromoxynil was noted for the first time. The investigation into the effect of different production practices (tillage and rotations) on the numbers of ryegrass plants in fields on the Langgewens experimental farm was continued. In July 2009 it was found that plots that received a mouldboard plough treatment had between 80 and 90% less ryegrass than plots receiving other tillage treatments. Minimum till plots showed the highest numbers of ryegrass and no till plots showed the second lowest ryegrass numbers. Similar results were obtained when a survey was made in September 2009 although the differences between the treatments were smaller with the mouldboard plough plots showing between 50 and 75% less ryegrass. Regarding rotational cropping systems, no differences between wheat monoculture and wheat rotations with other grain crops (canola and lupins) could be observed regarding ryegrass numbers. All rotations that include an annual pasture component however had between 90 and 95% less ryegrass plants than the pure grain systems. These results show that production practices can play a role in managing ryegrass problems in the presence of herbicide resistance.


6.20

 

An investigation into the production dynamics of eight crop rotation systems, including wheat, canola, lupins and pasture species in the Swartland, Western Cape


JA Strauss, MB Hardy and SJA Laubscher
Institute for Plant Production, Department of Agriculture: Western Cape

Despite low rainfall and dry soil conditions in April/early-May climatic conditions during 2009 were favourable for dry-land crop and pasture production at Langgewens. Average rainfall was experienced over the growing season (April to October) and rainfall following late planting (mid May) was well distributed. A total rainfall of 306 mm was recorded for the period April to October. The wide-spread, high rainfall events that occurred in the Swartland, during November (data not shown) did not affect the yields recorded at the trial site as the crops had been harvested before they occurred.

Wheat production – Management protocols developed by the Technical committee were followed but adjusted during season as a function of variable climatic conditions. Mean wheat yield over all systems was 3490 kg/ha. This is approximately 400kg/ha less than the "adjusted" yield for the 2008 season. As has been recorded over almost all seasons (2005 was an exception) there were differences in yield among the different crop sequences. Wheat yields following legume pasture were on average greater than wheat yields in all other systems.

Data collected to determine number of ears per plant indicated that an average of 1.8 ears per plant were obtained over all crop sequences. It was clear from the data that ear density (ears m-2) and the number of ears per plant, were greater where wheat followed a legume pasture than when wheat followed wheat. Most of the grain delivered to the silo fell in the B1 or B2 class.

Canola & lupin production – Canola was planted on the 11th and 12th of May. Three weeks later some of the camps planted to Thunder TT and one camp planted to 44Y06 showed very poor or no emergence at all. After closer inspection of these camps a few possible causes were identified including poor seed vigour, snails and diseases and it was decided to replant these camps on the 10th of June.

The actual yields obtained during harvesting ("straight") ranged from 492 kg/ha to 1992 kg/ha. On average, actual canola yield after medic pasture (1428 kg/ha, including a camp that was replanted) was higher than the average canola yield after wheat (801 kg/ha).

The average actual yield of canola over all plots was 945 kg/ha and the average crude protein (% CP) over all plots was 21.8 % and the % oil content averaged 33.46% (Elsenburg lab).

Average lupin yield over the three plots that were harvested was 587 kg/ha. Camp 40/1 was not harvested. The possible explanation for the poor yields could be ascribed to the dying off of lupins due to water-logging. In addition a severe ryegrass infestation in these camps would also have contributed to the poor yield. The average crude protein content of lupin seed was 27.24%.


6.21

 

Economic sustainability of short- and long-rotation crop / pasture production systems in the Southern Cape


MB Hardy, JA Strauss and W Langenhoven
Institute for Plant Production, Department of Agriculture: Western Cape

2009 was the 8th year of production. The trial comprises two main components namely: short-rotation systems that are being tested at Tygerhoek experimental Farm at Riviersonderend and long-rotation systems that are being tested on farms in the Riversdale and Swellendam districts respectively. 2009 was the 3rd year of the 2nd 5-year cropping phase that is being tested at the Riversdale and Swellendam sites.

All trial areas were planted and managed according to the planned protocols (including appropriate weed, disease and insect control measures).

Both the Riversdale and Swellendam site received adequate rainfall during the season, which resulted in very good wheat (both sites) and barley (Swellendam) yields. The canola and lupin plots at Swellendam however did not reflect the rainfall season at the Swellendam site, while lupins planted at Riversdale did splendidly.

At Tygerhoek poor soil moisture delayed planting until early to middle May. During the months of June, July and October received rainfall above the long-term average for the site, while the rest of the growing season saw below average rainfall. Al crops however showed good returns on yield.

Wheat production – Wheat was planted at all three sites (SST 027).

Yield at the Riversdale site varied between 3.6 and 4.2 tons/ha. This yield reflects the favourable soil moisture conditions at the research site despite the relatively low rainfall during the latter part of the season.

Grain harvested at the Swellendam site averaged 1431 kg/ha. This reflected the good rainfall received.

At Tygerhoek the average wheat yield was 3306 kg/ha-1 over both replicates. Although the season started late, the above-average yields received in June, July and again in October helped to ensure a favourable harvest.

Grain was classed as B2 at both the Riversdale, B3 at Swellendam and B1 at the Tygerhoek site.

Barley production – Barley (SST 564) was planted at the Swelledam and Tygerhoek sites.

Average yield at the Swellendam site was 1606 kg/ha.

At Tygerhoek barley yields ranged from 2.4 to 3.7 tons ha-1. These yields were higher than those of the 2008 season.

Oats production – Oats (Pallinap) was planted only at Tygerhoek. Seed production ranged from 2.8 to 3.5 tons ha-1.

Canola production – Canola (Jade) was planted at Riversdale. Although an adequate stanch was obtained a mistake in herbicide application resulted in all canola plots being killed off, with no resulting harvest.

Jade was planted at Swellendam at 3kg seed/ha and with 20kg N/ha at planting.

Canola (Thunder) was planted at Tygerhoek. A seeding rate of 3.3 kg/ha was used and a total of 80 kg N/ha was applied to each plot (20kg N/ha at planting and 60kg N/ha topdressings).

Canola yields at Swellendam averaged 435 kg/ha. These yields were not reflective of the season and could be due to poor germination at the start of the season and harvest losses.

The average canola yield over all plots at Tygerhoek was 1362 kg/ha, which is excellent in comparison to the expectations of the region. Very strong winds and heavy rain during the ripening period resulted in heavy losses.

The oil percentage of the canola ranged from 39% to 41%.

Lupin production – Lupins (Mandelup) were planted at the three sites. The Riversdale site produced yields ranging from 1.8 to 2.4 ton/ha. At Tygerhoek yields varied from 2050 to 2860 kg/ha. The Swellendam site saw heavy losses during the harvest process. Yield at the site averaged 645 kg/ha. Losses were calculated at an average of 500kg/ha. The heavy losses could be attributed to harvest timing.

Economics – The financial analysis program that was discussed in the previous report was completed during 2008 and is now being used to complete Gross Margin analyses of all years not included in the COMBUD data bases. The 2007, 2008 and 2009 data sets for Tygerhoek have been captured and we are busy verifying the results.


6.22

 

The identification of soil parameters as indicators of sustainable dry-land crop production systems for the shale derived soils of the Western Cape: tillage practice, crop rotation, soil quality and crop production


J Labuschagne
Institute for Plant Production, Department of Agriculture, Western Cape

The aim of this project is to quantify the effects of tillage practice and crop sequence on soil physical and chemical properties, and soil biological activity towards gaining a better understanding of soil parameters that will promote sustainability in crop production systems on the shale derived soils of the Western Cape.

Tillage treatments and planting

Tillage treatments were done timorously at the Tygerhoek site, resulting in relatively firm seed beds before planting the minimum and conventional-till treatments. At the Langgewens site however, ploughing of the conventional-tillage treatment was late resulting in a relatively loose seedbeds that caused problems with achieving constant planting depth on the minimum and conventional-till treatments.

The weed (ryegrass) problem on the zero-till treatments continued during the 2009 wheat production season. Relative low weed populations in all treatment combinations allowed harvesting of the wheat and canola crops at Langgewens and all crops at Tygerhoek. The lupin at Langgewens was sprayed with a non-selective herbicide as the lupin crop was overgrown by weeds (regardless of tillage treatment) as a result of waterlogged areas and Phytophthora. This herbicide application was delayed as late as possible (just before viable weed seed were produced) to ensure maximum "crop effect" on the soil in the lupin plots.

Climatic conditions

Climatic conditions during 2009 were relatively good for dry-land crop production on both Tygerhoek and Langgewens. At Tygerhoek and Langgewens 322.6 and 333.1 mm of rainfall were measured respectively for the period April to October 2009. Temperatures remained mild on both sites.

Crop production data

Seedling/plant densities

Relative low seedling/plant densities for wheat were recorded at both sites. The wheat crops at both sites recovered, in particularly Tygerhoek, and recorded mean ear bearing tiller counts of between 182.87 and 262.10 tillers/m². At Langgewens the canola plots were replanted (10 June), but due to the short growing season did not allowed enough time for optimum vegetative growth and reproductive development. The lupin plant count of 40.75 plants/m² at Langgewens was slightly lower than the 45 plants/m² aimed for at planting. Waterlogged conditions and Phytophthora caused damping off of lupin plants at Langgewens followed by weed infestation. To combat viable weed seed production it was decided to spray the lupin crop at Langgewens using a non-selective herbicide.

Grain yield

As a result of low plant populations, waterlogged conditions and the incidence of Phytophthora in the lupin crop at Langgewens, weed populations increased and it was decided to spray all lupin treatments at Langgewens as well as the zero-till treatments at Tygerhoek with a non selective herbicide. A mean lupin yield (excluding the zero-till treatment) of 1903.07 t/ha was recorded at Tygerhoek.

The mean canola yield at Langgewens was extremely low at 434.43 kg/ha. A relative low mean yield of 1418.26 kg/ha was recorded at Tygerhoek.

Wheat yields were lower than expected. The zero-till treatments recorded the lowest (2409.28 kg/ha) and the no-till the highest (2952.43 kg/ha) grain yields at Tygerhoek. The same response was noted for Langgewens with the zero- and no-till treatments producing 1746.28 and 2858.03 kg/ha respectively.

Thousand seed weight

As a result of the relative short canola growing season at Langgewens, the 2.209 g thousand seed weight recorded was considerably lower than the 3.9503 g recorded for Tygerhoek. Although differences between tillage treatments were recorded at Tygerhoek, no trend was observed.

The thousand seed weight (TSW) of wheat (SST 027) was at similar values for both sites with no definite trend observed.

Grain quality

Tillage practice did not influenced hector litre mass or protein content of wheat at Langgewens. Except for the zero- till treatment at Tygerhoek, that resulted in lower (P=0.05) grain protein content, were no differences found between the tillage treatments tested. No trend regarding the effect of tillage treatment on hector litre mass was found for the Tygerhoek site.

Base-line studies – various base-line studies has been completed and will provide comparative background information for use in future detailed investigations of soil chemical, physical and microbiological dynamics. These studies included collection of 1) soil chemical and physical data 2) soil microbial diversity and enzymatic activity 3) nematode populations 4) weed seed banks and 5) soil-borne diseases.

Concluding remarks

The project is progressing according to the research proposal and protocols. The severe ryegrass problem, especially in the zero-till wheat treatments, is being managed without compromising the integrity of the treatments and their potential effects on the physical and chemical status of soils. Short-term effects of tillage system, crop sequence and site on crop yields should become more apparent over time.


6.23   A:

Enhancement of canola as a rotation crop within a conservation system in the dry land areas of the Swartland using a competition between producers


IF Slabbert
Department of Agriculture: Western Cape

Sixteen farmers entered the Canola Competition in the Swartland. Information from all sixteen competitors could be used.

Although the first rains were somewhat late for a good Canola potential, favorable weather conditions persisted until September. However the rainfall during August was below average. Thus the average yield of the participants was 1.29 ton/ha, which was 0.05 ton less than in the previous year (2008).

Mr Dirk Lesch from Malmesbury was the participant with the highest yield (1.86 ton/ha). Dirk Lesch was also the participant with the highest gross margin (R1309/ha).

The runners-up were from Moorreesburg, namely Mr Albertus Truter (1.75 ton/ha) and from Porterville, Mr Jacques Louw (R1262/ha).

Canola was more profitable than wheat during 2009. However the gross margin for Canola was on-average R1000/ha lower than in 2008 mainly because of the lower price.


6.24   B:

 

Enhancement of canola as a rotation crop within a conservation system in the dry land areas of the Southern Cape using a competition between canola producers


JG Loubser
Contractor, Protein Research Foundation

Twenty four canola producers entered the Southern Cape Canola competition in 2009. The information from all the entrants was processed and included in the report. The results were released and discussed on the 2 March 2010 at the annual Overberg Agri Pre-planting Information Day at Rietpoel near Caledon.

Moist to dry soil conditions prevailed during the planting season from mid April until mid May, followed by good rains during June and July. During August and September the rainfall was good, except for the eastern production areas at Swellendam. During August and September moisture stress was experienced in these areas.

The average canola producers' price was R2,903 per ton, the average yield was 1.640 tons per hectare and the average gross margin R1,315 per hectare.

The Theunissen Family Trust of the farm Haarwegsrivier near Rietpoel was the participant with the highest yield of 2.773 tons per hectare and the best gross margin of R5,220 per hectare.

Mr Andrew Beukes of the farm Vrede near Caledon was the participant with the second highest yield of 2.270 tons per hectare.

Mr Adriaan Steyn of the farm Wankie near Swellendam was the participant with the second best gross margin of R3,331 per hectare.


6.25

 

Insect and other pests of canola


G Tribe and A Lubbe
ARC-Plant Protection Research Institute

The main trial consisting of 6 treatments and 5 replications carried out on two farms in the Caledon district showed once again that the main culprits responsible for the loss of seedlings were isopods. Each treatment had 5 melthoid traps under which the numbers of isopods and slugs were counted, and 4 demarcated areas (1 x 0.5 m) in which the number of seedlings was recorded at weekly intervals. There was a negative correlation between the number of isopods and the survival of seedlings. Slug pellets containing a combination of 30g/kg metaldehyde + 20g/kg carbaryl broadcast at a rate of 8kg/ha at planting was most effective in protecting seedlings. Cruiser treated seed plus slug pellets broadcast at planting did not increase the survival rate of seedlings, while metaldehyde treated seed was ineffective. The number of slugs recorded during this period was so low that no conclusions as to their response to the treatments could be drawn.

In a second trial 6 slug pellet formulations were tested against a Control by placing 8 gms of one or other of the formulations under 84 individual traps where the number of dead or alive slugs, isopods and other insects were monitored weekly. Snail Nail, Sluggem and Snail bait were extremely effective in attracting and killing both slugs and isopods when compared with the Controls. There was no significant difference in the ability of a special formulation with an increased level of carbaryl (30g/kg metaldehyde + 30g/kg carbaryl) in the number of slugs or isopods killed. The 50g/kg metaldehyde formulation (Clartex) was less effective in killing slugs and did not kill isopods.

Weekly monitoring of 120 melthoid traps on the farms Roodebloem and Speelmansrivier for slugs of all 4 species revealed that they were not randomly distributed. The indigenous Oopelta polypunctata was found only under the traps at Speelmansrivier (2%) where fynbos occurred at the edge of the field and they were active only late in the season and therefore posed no threat to canola seedlings. The slug species which predomi­nated in numbers on both farms (58.7% + 62.2%) was the exotic Deroceras panormitanum which peaked in numbers from late August and was still present at harvesting. Milax gagates appeared early in the season and peaked in numbers between late July until the end of August and consti­tuted 41% of the slugs at Roodebloem and 14% at Speelmansrivier. Deroceras reticulatum was almost exclusively found (21.4%) at Speelmans­rivier. When the total numbers of all four species of slugs are combined at weekly intervals over the season, slug numbers increased rapidly in the last week in May and remained active at this level until the end of August after which their numbers decreased just as rapidly. This activity peak coincided with bouts of rainfall and lower temperatures as would be expected. However, isopod activity indicated that they were less dependent on rainfall and were active early in the season (April); their numbers under the traps decreased during bouts of rainfall and peaked between July and October although weekly numbers fluctuated more widely at the end of the season as conditions began to dry out.

The parasitism rate of the diamondback moth (Plutella xylostella) was 18.8% which has remained at similar low levels for the last three years. The late-larval parasitoid Diadegma mollipla accounted for 65% of this parasitism. Damage by the cabbage aphid Brevicorne brassicae was negligible because it was brought under control within two weeks by the parasitoid Diaeretiella rapae. Numbers of the cabbage stem weevil Ceutorhynchus pallidactylus per canola stem decreased to an average 0.3 as opposed to 17.8 in 2008.


6.26

 

Characterization and management of Rhizoctonia on canola and lupin in cropping systems in the Western Cape Province


SC Lamprecht
ARC-Plant Protection Research Institute

Several methods with potential for the management of Rhizoctonia diseases of canola and lupin including plant resistance, fungicide seed treatment and biological control using binucleate Rhizoctonia anastomosis groups (AGs) were evaluated under glasshouse conditions. Screening included the examination of resistance of eight canola and eight lupin cultivars/selections to damping-off and hypocotyl/root rot caused by the multinucleate Rhizoctonia solani AG-2-1, 2-2, 4 and 11. All canola cultivars were highly susceptible to AG-2-1, although they differed in their reaction. Spectrum and 44C73 were more resistant to AG-4 than the other canola cultivars. On lupin, R. solani AG-2-2 and 4 were most virulent, and the cultivar Cedara 6150 and selection E16 were most resistant to AG-2-2, while Cedara 6150, E16, Mandel-up and Quilinock were more resistant to AG-4 than the other cultivars/selections. The Lupinus luteus selections, E80.1.1.2 and E82.1.1 were most susceptible to AG-2-2, 4 and 11. Seed treatment with the fungicides, Cruiser OSR (a.i. difenconazole, fludioxonil, metalaxyl-M, thiamethoxam) and SA-combination (a.i. iprodione, metalaxyl, thiram) significantly increased survival of canola (cvs Muster, Rocket and Thunder) and lupin (cultivar/selection Cedara 6150, E82.1.1 and Mandelup) seedlings, decreased hypocotyl/root rot and improved the percentage healthy seedlings, with SA-combination being significantly more effective than Cruiser. Application of the binucleate Rhizoctonia AGs (A, Bo, K and I) significantly increased the survival of lupin seedlings inoculated with R. solani AG-2-2 and 4, and AG-I and K significantly improved survival of canola in the presence of AG-4. A low inoculum ratio of the binucleate AGs [1:1 (multinucleate AG :binucleate AG)] was less effective than a high inoculum ratio [1:10 (multinucleate AG :binucleate AG)]. It appeared that AGs-A, Bo and I were more effective than AG-K in protecting lupin from infection by R. solani. This is the first report of the potential of binucleate AGs to protect canola and lupin seedlings against infection by multinucleate AGs. Results obtained in this study will significantly contribute to management strategies that can be employed against Rhizoctonia diseases of canola and lupin in the Western Cape province of South Africa.


6.27

 

The effect of raw full fat soybeans versus heat-treated full fat soybeans on the feed intake, feed efficiency ratio and growth rate of finishing ostriches


TS Brand and BB Aucamp
Institute for Animal Production, Department of Agriculture: Western Cape

Soybeans are a well-known protein source for farm animals, but are well-known for the fact that they contain the anti-nutritional factor trypsin inhibitor, which is known to interfere with the effective working of certain digestive enzymes. Trypsin inhibitor is however inactivated by heat treatment. The study was done to determine to what extent the inclusion of raw soybeans in ostrich diets will affect their performance. Under a free choice situation diets containing respectively heat-treated full fat soybean meal, raw full fat soybean meal or a 50:50 mixture of full fat/raw soybean meal as protein source were fed to finishing ostriches, while the intake of the respective diets was recorded. In a production study, finishing ostriches received diets with the same ingredients, while the most important production parameters were recorded. Feed intake under a free choice situation tended (P=0.10) to be higher for the diet containing heat-treated soybean meal compared to the diets containing either the 50:50 mixture of raw and heat-treated soybeans or the raw soybean meal containing diet. The feed intake of birds receiving the heat-treated soybeans containing diet was significantly higher (P<0.05) than that of birds that received either the 50:50 mixture of raw and heat-treated soybeans or the raw soybean meal containing diet. The growth rate of the three groups of birds were respectively 130 g/bird/day (heat-treated soybean containing diet), 82.3 g/bird/day (50:50 mixture of raw and heat-treated soybeans) and -47.9 g/bird/day (raw soybean meal containing diet). Feed conversion ratios were similarly negatively affected by the inclusion of raw soybeans in the diets. The data revealed that the inclusion of raw soybeans as protein source in ostrich diets will adversely affect the primary production parameters and is therefore not recommended.


6.28

 

Development of a simulation model to optimise the feeding of broiler breeder hens during lay


RM Gous
Animal and Poultry Science, School of Agricultural Sciences and Agribusiness, University of KwaZulu-Natal

The objective of this research project is to produce a simulation model that can be used by nutritionists to optimise the feeding of broiler breeders. A considerable amount of research has been conducted at the University of KwaZulu-Natal on broiler breeders, mainly concerned with the effect of photoperiod on the attainment of sexual maturity and subsequent laying performance. This, together with the mathematical model describing lay­ing patterns, potential egg production and egg weight that has been developed here, has enabled us to develop a simulation model that describes the potential egg output of broiler breeders during lay. Describing potential performance is the first step in being able to model the effect of food composition and allocation on the laying performance of broiler breeders.

The model simulates the response of a population of broiler breeders to a daily allowance of a feed of specified composition for up to 280 days from sexual maturity. Assumptions for protein partition rules are that maintenance has highest priority, yolk protein deposition second and albu­men protein third. All events are timed within a 24-hour day assuming that feeding is at one time in the morning. By making use of published theories and results the model will become sufficiently accurate to be used in designing feeds and feeding programmes for broiler breeders, thereby conforming to the PRF principle of the dynamic promotion of the implementation of research results. It is hoped that this model will convince broiler breeder producers in South Africa that they are currently feeding excessive amounts of both energy and protein to their hens, the consequences being lower egg production, higher egg weights, excessive fat deposition and lower enterprise profitability.


6.29

 

Amino acid and protein utilization of broiler breeder hens fed maize-soya diets


M Ciacciariello
Animal and Poultry Science, School of Agricultural Sciences and Agribusiness, University of KwaZulu-Natal

For a broiler breeder hen to maximize the utilization of dietary amino acids and protein offered to her, the amounts of these nutrients and energy supplied in her daily ration must meet her requirements for these nutrients for maintenance and egg production, but should not be more than marginally in excess of those requirements. Because the nutritionist makes decisions about the amount of food to be supplied to the hens daily, it is imperative that the requirements for these nutrients are accurately predicted and measured. Because so little research has been conducted on these birds, many questions still arise regarding the calculation of the daily nutrient requirements of these hens, such as the need to provide nutrients for growth, for thermo genesis and for feathering, whether the supply of energy can be reduced in cold weather, and whether they can make use of body lipid reserves for a period when energy supply is lower than demand.

The major objectives of the research in the past year have been to measure the response of broiler breeder hens to a range of environmental temperatures as a means of determining their nutrient requirements for maintenance and of overcoming heat stress during the summer months, and of the effects on performance over the entire production period of feeding a range of dietary protein and energy levels that either change or remain the same as the laying period progresses. Measurements taken have included the deep body temperatures of individuals to determine the extent to which this varies during the day, for example after the feeding period and during periods of rest. The results will be used to improve our understanding of the nutrient requirements of these birds over the entire laying period.


6.30

 

Questionnaire relating to canola production


F Slabbert¹, JG Loubser² en GA Agenbag³
¹ Department of Agriculture, Western Cape; ² PRF contractor; ³ Stellenbosch University

Questionnaire pertaining to canola production

The primary goal of the study was to determine, by means of questionnaires, why existing canola producers don't plant larger areas of canola. A second questionnaire aimed to determine why other producers do not plant canola.

Questionnaires were completed by visiting the farms of 65 producers in the Swartland (35 canola producers and 30 producers that do not cultivate canola) and 64 producers in the Southern Cape (34 canola producers and 30 that do not cultivate canola).

All the information was captured on Excel spreadsheets and summarized. This summary showed comparative results for canola producers and non-producers of canola in the different farming areas.

In the Swartland and the Southern Cape regions 10.93% and 9.59% of the workable dry land of canola producers respectively is utilised for the cultivation of canola.

The potential for the expansion of canola production is the highest in the Swartland. This is due to the fact that only 15.81% of the workable dry land is used for the production of medics. On the other hand 47.08% of the workable dry land in the Southern Cape is utilised for the production of lucerne. Expanding canola production in the Southern Cape will require current canola producers to plant canola more frequently than once every four years. Focusing on recruiting new canola producers will have to made a priority.

The importance of planting canola is in the advantages obtained for crop rotation and increased grass weed control which is found in such systems.

Producers who do not plant canola maintain that problems regarding the harvesting of canola, the precariousness of yields and economic factors are the main reasons why they don't sow canola.

Producers who do sow canola also identified losses incurred with the harvest of canola as the main problem. The problem with snails in the Southern Cape was also stated as an important issue.

Current canola producers in both regions are positive about the canola industry and are planning to cultivate larger areas of canola.


6.31

 

Income and cost budgets


JSG Joubert
Protein Research Foundation

During the reporting year, economic and technical/biological information was obtained from agricultural businesses, but also by means of group discussion sessions within the areas where information could not be obtained from agricultural businesses.

In the Swartland area of the winter rainfall region, information was obtained using the group discussion method. It involves expert producers in terms of area and particular expertise about the crop branch involved. They are invited to render input. The group discussions take place in co-operation with other experts involved with the Department of Agriculture, and agriculture businesses. In the Southern Cape and Overberg/Ruens area, all the information was obtained from agricultural businesses. For these two areas, income and cost estimates for barley were calculated for the first time. There is a distinction between the types of systems (where the information is available). In the summer rainfall areas, all income and cost estimates in Mpumalanga and KwaZulu-Natal were obtained using the group discussion methods. The rest of the information was obtained from agricultural businesses. Income and cost estimates for wheat in the VKB area were included for the first time, because it is considered an important competing crop in the area. There is a distinction between processing systems in these cases too. Sensitivity analyses are included for canola in the winter rainfall area and soya in the summer rainfall area, for inclusion in all budgets.

In terms of the summer rainfall area, crop estimates were prepared for the following areas:

Mpumalanga – Kinross
– Middelburg
– Groblersdal (Irrigation)
North West – Brits / Koedoeskop / Makoppa (Irrigation)
– Koster
– Lichtenburg / Coligny
– Zeerust
Eastern Free State – VKB-area
KwaZulu-Natal – Karkloof
– Vryheid
– Bergville (Irrigation)

In terms of the Winter rainfall region in the Western Cape, crop budgets were prepared for the following areas:

Western Cape – Moorreesburg
– Malmesbury
– Porterville
– Caledon / Riviersonderend
– Bredasdorp / Napier
– Swellendam / Heidelberg

The information contained in the income and cost estimates typically reflect situations under normal climatic conditions. They do not represent an average for a particular area. It contains information per hectare, showing gross income, variable income and gross margins. Existing and pro­spective producers may use the information to prepare budgets for their own enterprises, particularly in the decision-making process. The PRF feels that the information made available at significant effort and costs, is being underutilised. In future, the matter will be addressed, to allow better utilisation of the information in the technology transfer process.


6.32

 

PRF website


The PRF web site is a very important communication tool. Relevant information is made available to role players and those requiring subject-specific information.

Links to other web sites remain an important way to promote the PRF and in this reporting year new links were established with two important institutions. The PRF succeeded in securing a link with "National Variety Trials", an Australian web site, as well as the "Iowa State University" web site, the latter being involved with a great deal of research relating to soybeans.

The database which was loaded on the web site in 2007 enjoys high priority. Due to the hard work of our administrative staff, particularly Ms Du Preez, large amounts of historical data, previously stored elsewhere, are now being included on our database.

Search engines remain the most important source of reference to the PRF web site. More than 60% of people looking for our web site are referred by search engines. In certain cases, this figure has been as high as 70%. The importance of search engines varies from month to month, but those that are shown regularly as a source of reference are Aardvark, Google, SABA and SAGIS. From 2004 to 2008 the number of visitors increased significantly, with a slight decline in the number of visitors during the current reporting year. The figures below show the number of annual visitors:

Reporting Year

Number of Visitors

2004
2005
2006
2007
2008
2009
  1 691
  3 285
  4 552
  5 404
11 104
  8 484

In the next reporting year, a dedicated effort will be made to market the website, particularly aimed at the marketing campaigns that the PRF has launched in terms of soya and canola.