Monitoring farming systems - effects of cropping practices - limitations to wheat yields
1989
Wegener, P.F. | McDowall, C.J. (South Australian Dept. of Agriculture, Turretfield) | Frensham, A.B. (South Australian Dept. of Agriculture, Adelaide. Support Services Div.)
Survey techniques were used to assess the potential long-term consequences of increased cropping intensity on wheat yields and the relative importance that other edaphic and biotic factors have on wheat productivity. The survey revealed that increased cropping intensity was positively associated with higher grain yields, which may be due to better weed and disease control. It also lead to poorer soil structure and decreased soil organic matter. It seems possible to intensively crop the red-brown earth soils for relative long periods without affecting yields despite the resultant deterioration in soil conditions. It is unclear whether continuous cropping will eventually result in decreased crop yields through nutrient exhaustion and soil deterioration or whether, given appropriate management, high crop yields can be maintained with lower levels of organic matter and poorer soil structure. High grain yields were achieved under a wide range of cropping intensities if the crops were sown early, weeds were controlled at an early stage and adequate N was available to the crop. Useful practices for increasing yields include fallowing, use of grain legumes, maintaining legume dominant pastures and application of N fertilizers.
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