a farmer had been growing wheat for the past three years.this time the crop is not giving him enough produce.What do you think he should do to improve the yield of his crop?Why?
Answers
Disease control
The most significant benefit of break crops to following cereals is the reduction in soil and stubble-borne disease. In Australia for example, the yield of wheat after canola or linseed crops has averaged 20 percent higher than for wheat, after wheat largely because of disease reduction.
The dominant pathogens within a crop sequence differ between environments, soils and seasons. You must identify the pathogens in your system and understand what influences their activity if you want to realistically assess the chance of success of a crop sequence.
Impact of a break crop on the incidence of ‘whiteheads’ in a following wheat crop
J.A. KIRKEGAARD
Nitrogen benefits
In addition to providing a disease break, grain legume break crops such as peas, lupins, lentils and chickpeas may provide residual N to following wheat crops.
In some regions these benefits have boosted yields of following wheat crops by up to 50 percent, similar to the effects of applying adequate N fertilizer out of a bag. However, the magnitude of the N benefit depends on effective N fixation by the legume, the amount of biomass produced and how much N is removed in legume seeds or stubble.
Some non-legume break crops, such as linseed, may also leave any deep residual soil N untapped because they have a shallow root system and use soil N inefficiently. Since residual N influences both yield and protein content of following cereals, it is important to consider the N balance of the whole system when attempting to understand crop sequence effects (see chapter on Optimizing nitrogen use on the farm).