长期施用有机肥对土壤及不同粒级中有机磷含量与分配的影响

INFLUENCES OF LONG-TERM FERTILIZATION ON THE CONTENTS AND DISTRIBUTIONS OF FORMS OF ORGANIC P IN SOIL AND SOIL PARTICLE SIZES

通过在黄棕壤上开展的 14年田间定位试验研究稻 -麦水旱轮作下长期施用有机肥对土壤及不同粒级中有机磷的影响。结果表明 :与不施肥的对照和单施化肥相比 ,有机肥与化肥长期配合施用能显著增加土壤有机磷总量 ;就有机磷的形态而言 ,长期施肥主要增加中等活性有机磷的含量。土壤不同粒级中总有机磷的含量顺序为 :0～ 2 μm >2～ 10 μm >5 0～ 10 0 μm >10～ 5 0 μm。从分配系数上看 ,土壤有机磷各形态中以对植物有效性较高的中等活性有机磷占绝对优势 ,对植物有效性最高的活性有机磷仅占 3 %左右。长期施用有机肥后使分配在活性、中等活性组分中有机磷的比例增加 ,而稳定性有机磷中的比例下降。

The effects of manure application on the contents and distributions of fractions of organic P in soil and soil particle sizes were investigated in a field exper iment, which consisted five treatments of control (no fertilizers), chemical fer tilizers, chemical fertilizers plus straw, chemical fertilizers plus green manur e, and chemical fertilizers plus pig manure and had continued for 14 years at th e farm of Jurong Agricultural Science Institute. The crop rotation of the exper i ment was summer rice ( Oryza Sativa L. ) and winter wheat ( Triticum aestivum ). The results showed that compared with the treatments of control or single applicati on of chemical fertilizers, the combined application of organic manures with che mical fertilizers could significantly increase soil organic P. The contents of s oil organic P in different soil particle size fractions were in the followin g or der: 0～2 μm>2～10 μm>50～100 μm>10～50 μm. Long-term fertilization main ly incr eased the contents of moderately labile organic P which was a little bit availab le to plant absorption and accounted for a largest percentage of soil organic P no matter in soil itself or in different soil fractions. The labile organic P w a s also increased in long-term fertilization but its contribution to plant P nut rition was small since it accounted for only 3% of total organic P in soils. Fur t hermore, long-term fertilization could decrease the percentage of highly resist a nt organic P showing that fertilization could also activate the native soil P to improve plant P nutrition.