长期不同施肥下太湖地区黄泥土肥力的变化

对太湖地区典型水稻土———黄泥土进行了12年的长期定位不同施肥试验,并保持化肥的施用水平与本地区常规施用量相当。对12年来的肥力变化与不同施肥小区的肥力差异的分析研究表明,长期单施化肥下土壤耕层中养分都有所下降,且表层土壤养分的下降量不及亚表层土壤,年际间生产力不稳定。化肥配施有机肥(秸秆还田或猪粪),可长期保持土壤中的养分,稳定提高作物生产力;有机无机配合施肥下12年间全碳和全氮分别增加1.1g/kg和3.0g/kg,而全磷提高了0.3g/kg以上。同时也表明,表层土壤全氮的增加明显地促进了有机碳的固定。

Change of soil fertility under long-term different fertilization practices in a paddy soil from the Tai Lake region

A long-term experiment of different fertilization practices was conducted in a typical paddy soil in the Tai Lake region.The plots had been treated with chemical,chemical plus organic fertilizers for continuous 12years.The application rate of chemical fertilizers had been kept comparable to the conventional in the region.This paper reports a study on the changes of soil fertility and crop productivity of the plots over the 12 years of experiment.The results indicated that slow decrease of soil major and soil productivity occurred under chemical fertilization only while soil nutrients maintained and crop productivity stabled under the complexed fertilization of chemical and organic fertilizers.Furthermore,under the complexed fertilization,total C and N increased by 1.1 gkg~(-1) and 3.0 gkg~(-1) and total P by 0.38 gkg~(-1) respectively as compared with that before the experiment.The increase of N in soils benefited C sequestration in the paddy soils.