长期定位施肥对设施菜田土壤肥力的影响

本试验是长期定位施肥的继续 ,在保持原有的几个偏施氮肥处理的基础上 ,于 1997年增加了配施磷、钾肥的处理。研究表明 :长期单施无机N肥 (不施有机肥 )土壤有机质含量下降 ,施N量越大下降越多 ,而有机肥与N肥配施更有利于土壤有机质的提高。P肥的后效很长 ,不只是对当季作物 ,而且对以后的作物都有很好的后效。速效K含量下降迅速 ,因此在土壤有机质含量较低的情况下应特别注意K素的施用。长期偏施无机N肥加速了土壤的板结 ,破坏了土体的正常结构 ,耕性变坏。

Effect of Long-term Stationary Fertilization on Soil Fertility in Plastic-tunnel

This experiment was a succession of long-term stationary fertilizing. Based on the prior treatments of nitrogen fertilizer application, it further included the treatments of applying P and K fertilizer. The findings were as follows: A long-term mono-application of inorganic N fertilizer (without application of organic fertilizer) coursed a decline of the content of organic substance in soil. The more amount of N fertilizer applied, the sharper the organic substance declined. The mixing application of organic fertilizer and N fertilizer increased the content of organic substance. P fertilizer has a long-term effect, which was beneficial to both present plants and the plants thereafter. The content of available K declined sharply. Therefore, attention should be paid to apply the K if the organic content in soil was low. A long-term N fertilizer application accelerated the hardenning of soil, destroyed the soil normal structure and made cultivation performance deteriorate .