Grain Guide 2018

Aim and guidelines for the use of cover crops In order to counteract and even reverse the process of soil degradation and climate change, producers should consider more sustainable and profitable practices like conservation agriculture (CA). One of the principles of CA is diversification and integration of crop and animal species, which includes the use of cover crops. Reasons for using cover crops  Restoration and improvement of soil health and biological diversity.  Improvement of resilience, risk and sustainability of crop rotation systems.  The economically and ecologically sustainable integration of livestock.  The sequestration of atmospheric carbon in the soil and therefore the combating of global warming.  The control and management of weeds, diseases and pests.  More effective use of water (from rain or irrigation). Guidelines for using cover crops  The suitability of cover crop species should be assessed on the farm in small demonstration or screening trials.  Assess the need for fertilisation, liming and irrigation.  Implement the correct plant, fertilisation, irrigation and weed control practices.  Use a suitable grazing practice – ultra-high density grazing is strongly recommended.  Manage grazing to provide good livestock production per hectare rather than production per animal. Functional plant groups  It is important to understand the properties and functions of the different plant groups.  Legumes are used the most for nitrogen contributions.  Grass crops are used more commonly to control soil erosion and weeds, for nutrient cycling and carbon sequestration, as well as to improve soil structure.  Brassicas are used to reduce soil compaction and improve soil structure, as well as to cycle nutrients and suppress diseases and weeds. Cover crop rotations and associations with cash crops The next section provides information on different cover crops that are grown together with, between or after cash crops. The emphasis falls on the summer rainfall area of South Africa. These crops should preferably be planted as a multi-species mixture and utilised by way of ultra-high-density grazing. The ideal situation is to have a variety of living roots in the soil throughout the year to improve the health of the soil. Guidelines for choosing cover crops 28 26 GRAIN GUIDE 2018 Seed