Soil inhabiting pests and rot of feeding roots of sugar beet depending on rotation - results of a long-term trial
1989
Schaeufele, W.R. (Institut fuer Zuckerruebenforschung, Goettingen (Germany, F.R.)) | Winner, C.
Over a period of 17 years a trial was carried out with sugar beet, cereals and oilseed rape in different crop rotations on a field near Goettingen (Lower Saxony). The frequency of sugar beet in the rotation was 17, 25, 33 and 67 per cent. In absence of beet nematodes, root and sugar yield of beet decreased after repeated growing of sugar beet in short rotations compared to variants with long rotations. Sugar content and beet quality were only slightly influenced. By applying a bioassay (BW-Test) with young beet plants in the greenhouse it was shown that increasing infections on the tips of rootlets of the beet plants were the cause for decreasing beet yield in close rotations. Mortality of young plants and progress of infection in the test indicated roughly the quantity of pathogenic fungi in the soil. In the roots of the baits plants the parasitic fungus Aphanomyces cochlioides predominated. Rate of infection and yield reduction in the field were decisively influenced by weather conditions. Differences in yield between sugar beet grown in a three-year and a four-year rotation, however, were not significant. An occurrence of beet pests depending on crop rotation was stated only for Atomaria linearis and this only in a few years
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