Productivity and stability of grain yield in wheat and maize as affected by rotational cropping systems in the eastern Free State

The use of crop rotation in the Eastern Free State to enhance profitability and reduce financial risk related to mono-cropped maize and wheat, has rekindled this research. The aim of this research was firstly to quantify the effect of dry bean, lupin, sunflower and fallow on the yield of a subsequent wheat crop arid secondly, to quantify the effect of soyabean and wheat on the yield of maize. Wheat after 18 months fallow, lupin, dry bean and sunflower yielded 40, 31, 25 and 54% more than monocropped wheat. With the exception of wheat planted directly after dry bean, crop rotation reduced the variability of wheat yields. The rotational effect of sunflower on wheat appears to be unique as it simultaneously increased the yield and stability of the yield, above that of the other systems. Yield of maize grown in rotation was slightly less variable than that of the maize grown in monoculture. Crop rotation improved the protein content of maize and wheat grain, as well as the hectolitre mass of wheat.