02154naa a2200289 a 450000100080000000500110000800800410001910000200006024500970008026000090017752013590018665000180154565000170156365000210158065000160160165000250161765000100164265300270165265300200167965300270169965300170172665300170174365300210176065300180178170000170179977300480181616079271995-06-27       1988    bl uuuu     u00u1 u    #d1 aBALTRUSCHAT, H.  aThe occurrence of vesicular-arbuscular mycorrhiza in agro-ecosystems.h[electronic resource]  c1988  aIn a long-lasting field experiment at the Research Station Hanninghof at Dulmen (Westphalia), laid out in 1971, the inoculum potential (IP) of vesicular-arbuscular mycorrhizal (VAM) fungi of soil from winter wheat in a continuous monoculture (CM) and in a four-years cereal crop rotation (CR, winter wheat, winter barley, winter rye, oats) was investigated from 1980 to 1982. The influence of green manure and two levels of nitrogen fertilization (100 and 200 kg ha-1) on VAM-IP was also assessed. It turned out that VAM is frequent also in intensively cultivated soils, but varies this with the crop rotation system and form and intensity of fertilization. Compared to CR the VAM-IP was significantly reduced in CM. A cumulation of this effect, with a particularly str ong decrease of VAM-IP was significantly reduced in CM. A cumulation of this effect, with a particularly strong decrease of VAM occurred when other factors unfavourable for the symbiosis coincided in CM. Among these factors were the use of non-mycorrhizal Raphanus sativus and Brassica napus for green manure together with a N-fertilization of 200 kg ha-1. On the other hand green manure and the higher N-fertilization resulted in less disturbance of the VAM-IP in the CR. A correlation between VAM-IP in the soil and of wheat yields could neither be observed in the CR nor in the CM.  acrop rotation  awinter wheat  aAdubação Verde  aNitrogênio  aRotação de Cultura  aTrigo  aAgricultural practices  aAgro-ecosystems  aContinuous monoculture  aGreen manure  aMicorriza/va  aN- fertilization  aVA mycorrhiza1 aDEHNE, H. W.  tPlant Soilgv. 107, n. 2, p. 279-284, 1988.