Field crop production systems and weed science
The increased production of nutritious cereal-, protein- and oilseed crops in a more sustainable and equitable way is pivotal to increase the food security of the burgeoning local and global populations. In developed countries these crops are also important sources of energy and protein in animal nutrition. For this reason the study field focuses on the optimal use of production inputs such as precision farming techniques to increase yields per hectare. Due to the worldwide concern about environmental pollution, attention is also being given to the use of crop-rotation which implies the use of new crops and conservation farming techniques to improve the sustainability of production systems. In addition the development of herbicide resistance in crop weeds also requires new weed control strategies. All these developments and challenges are dealt with in training courses and research program of the Department of Agronomy.
Pasture science is the study of the management of natural rangelands as well as planted pastures with the objective of producing the maximum amount of animal products such as meat, milk and wool with no detrimental effects on the pastures. The management of planted pastures includes efficient establishment, fertilization, utilization and harvesting of fodder crops. Aspects such as insect, disease and weed control are also important. One of the biggest challenges for the animal industry is the selection of crops that will be able to flourish under the hot, dry conditions caused by the greenhouse effect in certain areas of South Africa. Other problems include the development of resistance by weeds to herbicides, as well as the acidification and salinization of soils. Because of economical constraints the need also exists for sustainable, low input pasture crops. In this department, attention is focused on the management of herbicide resistance, as well as the role that legume pastures can play in improving soil fertility in rotational systems in the Mediterranean area. The management to natural rangeland involves the optimum utilization of natural fodder species with minimal damage to the environment. Ecological damage of the environment includes erosion, siltation of dams and rivers, dust storms and a decrease in production. Again the greenhouse effect is causing one of the biggest challenges in rangeland management. In certain areas of South Africa the prediction is that the annual precipitation will decline, and in conjunction with the higher temperatures this will lead to problems regarding the sustainable production of such areas. The reclamation of poor rangeland from the grip of erosion, bush encroachment and other ecological problems will also require judicious management principles to be implemented. Sound management therefore plays a very important role in the supply of food and animal fibres for human consumption, but also to conserve the environment for future generations.
It is widely acknowledged that the current practices of chemical agriculture have contributed to the decimation of key beneficial creatures (including fungi and bacteria) in the soil that facilitate mineral delivery to plants/crops. Farming practices, such as excessive use of inorganic fertilizers, can cause nutrient imbalances and lower pest resistance. It is imperative to re-establish the microbial balance of soils, thereby also restoring the potential of critically important services that are provided by mobilizing this hidden underground force. In addition, cultural methods such as crop fertilization can affect susceptibility of plants to insect pests by altering plant tissue nutrient levels. Research shows that the ability of a crop plant to resist or tolerate insect pests and diseases is correlated to optimal physical, chemical and mainly biological properties of soils. Soils with high organic matter and active soil biology generally exhibit good soil fertility, which may be correlated to lower abundance of several insect herbivores. The use of specific microbe antagonists, which stimulate plant growth and/or are natural enemies of pathogens, allows a considerable decrease in the use of agrochemicals that are now being used for plant growth and control of diseases. Illuminating our understanding of the underlying effects of how plant health is improved by associations with beneficial soil rhizo-microbes may lead us to new and better integrated pest management and integrated soil fertility management designs. This is urgently needed if we are to sustain food security of the most vulnerable groups of society indefinitely.
Hydroponics and Greenhouse Production
The production of crops in a soilless system in a structure where climatic variables can be controlled will be important for future food security. The production of a variety of crops including vegetables such as tomatoes, cucumbers, peppers and flowers such as tulips are being studied. The main research focus is looking at crop nutrition and irrigation and the effect of nutrient solutions on yield and quality of crops. Studies into alternative growing mediums are also being conducted as well as trellising and pruning systems for different crops. As a big advantage of growing crops in a greenhouse is the ability to control the climate, the effect of variable climatic factors on production is also studied including the use of artificial lighting such as LED technology. Novel systems such as vertical growing systems, aeroponics and aquaponics are also being evaluated and optimized for commercial application.
Potato Production Systems
Research is being conducted on novel methods of seed potato production. To increase the number of first generation seed potatoes hydroponic cultivation methods including aeroponics is being employed in potato production. These systems still needs optimization and therefore trials with different cultivars, using different planting methods and fertilisation practices are being evaluated. Post-harvest losses can result in big financial losses for potato producers so studies are also conducted on cultivation practices aimed at improving tuber quality. Ca has been identified as a key component to ensure tuber quality and application methods, timing of application and sources are still being evaluated. The role of other minerals is still being investigated.