The effects of long-term cultivation, without fertilizers, on crop yield of a grain-sugarbeet rotation and agrochemical characteristics of regraded chernozem.

摘要

Cultivation of crops without fertilizers on coarse silty medium loam regraded chernozem for a rotation of clover, winter wheat, sugarbeet, winter wheat, maize, maize, winter wheat, sugarbeet, barley + clover or peas[?] and a vetch-oats mixture was investigated over a 30-year period in the Ukraine. Crop yields of winter wheat, barley, peas and maize in the 3rd cycle of the rotation were not significantly less than corresponding yields for these crops in the 1st cycle of the rotation, whereas yieldsof sugarbeet decreased significantly. Marked decreases in crop yields in particular years were attributed to unfavourable weather conditions (high temperatures and reduced precipitation), with effects of these conditions being greater for barley and peas> sugarbeet > maize and winter wheat. After 3 cycles of the rotation, humus contents and base saturation in the 0-20 and 20-40 cm soil layers decreased, whereas acidity of these soil layers increased.