再生水灌溉对土壤团聚体中有机碳、氮和磷的形态及分布的影响

为了解再生水灌溉对砂质紫色土土壤有机碳、氮和磷的形态及其在不同粒级团聚体中分布的影响,比较了四川省彭州市灌溉年限分别为3a和8a的2个再生水灌溉区土壤中不同粒径团聚体中有机碳、氮和磷的分布及化学形态.结果表明,再生水灌溉区土壤有机碳、氮和磷主要分布在>2mm和2mm的大粒径团聚体所占比例下降,向较小粒径转化;>0.25mm团聚体中有机碳和氮含量显著上升,在所有5个粒级的团聚体中磷素含量都有显著提高.再生水灌溉还有利于紫色土重颗粒态有机碳和颗粒态氮的形成,且灌溉时间越长,效果越明显.在除<0.053mm的其它4个粒级团聚体中,再生水灌溉区土壤中交换态磷及钙结合态磷比例上升,而铁铝结合态磷比例下降.综上,再生水灌溉有效的改善了砂质紫色土土壤的有机碳库、氮库和磷库,长期灌溉可以减少人工施肥量.

Effect of reclaimed water irrigation on the distribution of organic carbon,nitrogen and phosphorus in different size of aggregates in sandy purple soil

Effect of reclaimed water irrigation on the organic carbon (C), nitrogen (N) and phosphorus (P) distribution regarding different size of aggregates in sandy purple soils was investigated. The studied soils in Pengzhou City had been irrigated with reclaimed water for varying lengths of time (3 and 8 years, respectively). In purple soil irrigated with reclaimed water, organic C, total N and total P were mainly distributed in the >2mm and 2 mm aggregate fractions of those increased markedly. Besides, organic C and N in >0.25 mm aggregate fraction in irrigated soils significantly rose, whereas P in all 5 aggregate fractions distinctly increased. Furthermore, reclaimed water irrigation was favorable for formation of particulate organic C and particulate N in irrigated purple soils, and such effect was increasingly greater over irrigation time. In aggregate fractions (except for <0.053mm), the proportions of exchangeable P and HCl-P increased, whereas NaOH-P diminished correspondingly. The study concluded that reclaimed water irrigation can improve the composition of organic carbon, nitrogen and phosphorus in purple soils.