The effect of incorporation time of different crops on the residual effect on spring cereals

The effect of the time of incorporation of different green manures and barley residues on the grain yield of spring cereals in two successive seasons was studied in seven field trials. Annual hairy vetch (Vicia villosa Roth), red clover (Trifolium pratense L.), westerwold ryegrass (Lolium multiflorum Lam. var. westerwoldicum) and straw of spring barley (Hordeum vulgare L.) were incorporated into the soil by ploughing in early September, late October and the following May, and by reduced tillage in May. Spring barley was established in the following spring, and spring oats (Avena sativa L.) one year later. In general the grain yield of spring barley after legumes was similar to that after barley, in spite of the fact that N fertilization was reduced by 40 kg ha-1. The two autumn ploughing treatments resulted in a good yield of spring barley more reliably than did the spring incorporations. Because delayed autumn ploughing did not decrease the grain yield, a delaying procedure can be recommended for its potential of decreasing nitrogen leaching. Spring ploughing could be used on all but clay soils. Incorporating ryegrass or red clover in spring by using reduced tillage often decreased the grain yield of barley. Timing of incorporation did not have a consistent effect on the grain yield of oats in the third experimental year.;