不同施肥模式下红壤性水稻土中磷的分布及其有效性

Distribution and Efficiency of Phosphorus under Different Fertilization Models in Reddish Paddy Soil

研究了不同施肥模式下红壤性水稻土中磷的分布及其有效性。结果表明,随团聚体粒径从大到小的变化,红壤性水稻土全磷含量在不同施肥模式下均表现出先上升后下降的趋势,在5～2 mm粒径团聚体中出现一个峰值;有效磷含量表现出先缓慢上升后迅速下降的特征,在5～2 mm粒径团聚体中出现一个大峰值;在施磷处理中,磷的有效率表现出先缓慢上升后迅速下降的特征,分别在5～2 mm和0.5～0.25 mm粒径团聚体中出现一个大峰值和一个小峰值,但在无磷处理中,磷的有效率表现出逐渐下降的趋势,只在0.5～0.25 mm粒径团聚体中出现一个小峰值。研究表明,长期施加磷肥,尤其与有机物还田相结合,会促使土壤全磷富集于>1 mm粒径团聚体,显著提高>2 mm粒径团聚体中有效磷含量与磷的有效性;在磷肥不足的情况下,减少磷肥施入量,结合有机物还田也能取得较好的效果;即使没有磷肥施入,实行秸秆还田也能在一定程度上提高土壤磷的有效性。

The distribution and efficiency of phosphorus under different fertilization models were studied in a long-term positioned fertilization experimental field at Taoyuan station of agro-ecology research, Chinese Academy of Sciences. The results showed with decreasing size of aggregates, total phosphorus contents in different size of water-stable aggregates increased first and then decreased with a peak value appearing in 5-2 mm aggregate; available phosphorus concentrations first ascended slowly and then descended rapidly with a peak value appearing 5-2 mm aggregate; moreover, the percentages of available phosphorus in total phosphorus displayed a higher peak value and a lower peak value in 5-2 mm and 0.5-0. 25 mm aggregates respectively, but in treatments amended without phosphorus fertilizer, they declined gradually with a peak value exhibiting in 0. 5-0. 25 mm aggregate. Therefore, long-term application of phosphorus fertilizer, especially combining with organic materials recycling, can result in concentration of total phosphorus on 2〉1 mm aggregates, and at the same time obviously improve plant availability and efficiency of phosphorus; in the event of no sufficient phosphorus fertilizer available, the profitable effect can be obtained under application of chemical fertilizers in combination with organic materials returning; even in the absence Of phosphorus fertilizer, the efficiency of soil phosphorus can be ameliorated to some extent through practice of straw recycling.