秸秆及土壤改良剂对植烟土壤微生物的影响

在云南通海、弥勒两地进行了1999年至2000两年定位试验，研究禾本科秸秆、土壤结构改良剂对土壤结构的改良作用，对试验各处理土壤微生物数量变化进行检测分析，结果显示：3种土壤改良措施在烟田和烟地的效应并不相同。土壤改良剂可迅速增加烟田土壤微生物的数量。施用小麦秆、玉米秆均不能在短期内明显改变烟田土壤微生物的数量。对长期试施用化肥的烟地，施用小麦秆和玉米秆都能增加土壤中微生物的数量，其中施加小麦秆的效果比玉米秆效果更好；而施用土壤改良剂则使土壤中的微生物数量降低。对长期化肥和农家肥配施的烟地，施用小麦秆和玉米秆均使土壤微生物数量下降，使用土壤改良剂则只能增加上层土壤中的微生物数量。

EFFECTS OF GIN STRAW AND SOIL CONDITIONER ON THE QUANTITY OF SOIL MICROORGANISMS IN TOBACCO FIELDS

In a two-year experiment conducted from 1999 to 2000 in Tonghai and Mile counties of Yunnan province, the effects of wheat and maize straw and a soil conditioner on the structure of the soil and quantity of soil microorganisms were investigated. The application of the soil conditioner caused a sharp increase in the quantity of soil microorganisms in tobacco fields, whether they were rain-fed or irrigated, while wheat or maize straw induced no significant change in the quantity of soil microorganisms in a short time. In a tobacco field which had received chemical fertilizers for many years, both wheat and maize stalk application increased the quantity of soil microorganisms, the effect of wheat stalk being better than that of maize stalk; in contrast, soil conditioner application reduced the quantity of soil microorganisms. In tobacco fields which had been enriched with farm yard manure in combination with chemical fertilizer, application of either wheat stalk or maize stalk reduced the quantity of soil microorganisms while the soil conditioner enhanced their quantity in the top soil layer.