Environmental situation of fodder beets.

摘要

A fodder beet [Beta vulgaris] crop was established after ploughing up a perennial ryegrass [Lolium perenne]/white clover [Trifolium repens] ley in France. After 10 months, 455 kg N/ha had been mineralized. The uptake capacity of beets was considerable, ranging from 400 kg N/ha at the beginning of September to 300 kg at the end of that month. The rate of N mineralization of the beet crop residues, as assessed in the laboratory, was 40%. Nitrate losses were estimated by simulation for three crop successions: ley (ploughed in April)/beet/wheat; ley/maize/wheat; and ley (ploughed in autumn)/wheat/wheat; they amounted respectively to 110, 270 and 240 kg NO3-N/ha for the 2 cumulated cropping years.