Crop rotation advantageous for sustainable farming in Western Cape

February 2010

MARK HARDY, INSTITUTE FOR PLANT PRODUCTION, DEPARTMENT OF  AGRICULTURE: WESTERN CAPE

A lot has been written and said about the importance and advantages of practising crop rotations on farms. Some of the main issues that have been extensively researched in long-term crop rotation trials being conducted by the Department of Agriculture: Western Cape, are considered below.

Monoculture
Monoculture is the practice of growing the same crop on the same land from one growing season to the next. Wheat monocultures were commonly practiced on many farms in the Western Cape (particularly in the (Swartland) mainly because such wheat monocultures maximised total farm income. The disadvantages of monocultures include more intensive production practices such as increased tillage, fertilization and pest (disease, insects and weeds) control inputs.

Input costs are therefore increased which, together with the current highly variable and often low “farm gate” price of wheat, result in greater financial risk to the producer. Another disadvantage of monoculture is that the production and quality of wheat is often lower than for wheat that is grown in rotation with an alternative crop or legume pasture. The lower yield and quality of wheat in monoculture are a result of increased presence of disease and competition from weeds. This further increases the financial risk to the producer.

Perhaps the greatest disadvantage of wheat monoculture is the major herbicide resistance problems that have emerged in the last decade. The development of herbicide resistant grass weeds (mainly ryegrass, but also (“predikantluis”) have ensured that wheat production based on monocultures will not be sustainable.

As a result of these problems mentioned above, grain producers can not ignore (and in most cases have not ignored) the benefits of crop rotation even though total farm income may decline.

Click on  http://php.grainsa.co.za/documents/SAGraan%20Febr10_Crop%20rotation.pdf  for the complete article.

Publication: February 2010

Section: Wenartikels