长期施肥对潮土硫、钙和镁组分与平衡的影响

本文以在潮土进行的 2 0年的长期肥料试验为例进行研究 .结果显示 ,单施化肥处理土壤有效硫出现耗竭趋势 ,而施用有机肥的处理则保持较高有效硫水平和由于所含钙磷肥和有机肥以及灌溉水中含有数量可观的钙 ,土壤水溶态钙和交换态钙含量除对照外 ,各处理间十分接近 ,各处理的钙均有赢余 ;由于有机肥对土壤镁素的补充作用 ,水溶态镁、交换态镁、酸溶态镁和全镁含量均表现为原始土 >单施有机肥 >对照 >化肥与有机肥配施 >单施化肥 ,即使在施用有机肥条件下 ,土壤镁素仍然亏缺

Long-term effects of fertilization on the balance of soil S, Ca and Mg in fluvio-aguic soil

A long term fertilization experiment has been carried out for 20 year on fluvio aguic soil. It was found that soil available S was almost exhausted gradually when mere chemical fertilizers were applied, whereas its level was relative high in the treatment with organic manure only. Both water soluble and exchangeable Ca were rich and its content was similar in all treatments except for the control due to the fertilizers and irrigation water containing Ca. The status of Mg was different from the above two elements. Water and acid soluble, exchangeable and total Mg behaved similar but were affected by fertilization differently, and hence the concentrations of the three forms were in the order: oringinal soil>organic treatment>control>chemical tertilizer plus organic fertilizer>chemical fertilizer. Nevertheless, soil Mg was still poor even in the organic treatment.