不同菜地土壤中磷积累的形态变化特征研究

长期施用化肥和畜禽粪可导致土壤中磷的积累,从而影响土壤中磷的生物有效性和可移动性,后者与土壤中磷存在的化学形态有关。为了解蔬菜地土壤磷积累过程中其化学形态的演变与土壤性状的关系,选择了红粘泥、黄筋泥、泥质田、淡涂泥和油黄泥等5种不同性状的土壤,通过添加化肥和猪类模拟构建了不同磷积累的系列土壤,采用Hedley磷形态分析方法鉴定了土壤磷的化学形态及释放法潜力。结果表明,与未加磷处理土壤相比,所有蔬菜地土壤中磷的积累对H₂O-P和NaHCO₃-IP增幅影响最大；在中性和石灰性土壤中,磷积累可明显促进HCl-P的形成,但对NaOH-IP的影响较小；在富铝化土壤中,磷的积累有利于NaOH-IP的形成,但对HCl-P形成的影响较小。无论是施化肥还是有机肥,土壤中积的累磷主要为无机态,对有机态磷的贡献较小；随着土壤磷的不断积累,磷积累对H₂O-P和NaHCO₃-IP的影响更为明显。

Change Characteristics of Phosphorus Accumulated Form in Different Types of Vegetable Soil

Long-term application of chemical fertilizer and livestock and poultry manure can lead to the accumulation of phosphorus in soils, and thus influence soil phosphorus bioavailability and mobility. The bioavailability and mobility of phosphorus in soils are related to chemical forms of phosphorus in the soils. To understand the evolution of chemical forms of phosphorus accumulated in vegetable soil, five kinds of soils with different properties and chemical components, including bole soil (allite soil), quaternary red clay (allite soil), pale fluviogenic loamy paddy soil (neutral soil), desalting muddy polder soil (neutral soil) and waxy brown limestone soil (calcareous soil), were collected for the experiment. Chemical fertilizers or organic manure were added to the soils to build a series of soils with different phosphorus accumulation. Chemical speciation and release potential of phosphorus of the soils were characterized by Hedley phosphorus fractionation. The results showed that accumulation of phosphorus in all soils had greatest effects on relative increase of the H₂O-P and NaHCO₃-IP, as compared with control soils without addition of phosphorus. In neutral and calcareous soil, phosphorus accumulation can significantly promote the formation of HCl-P, but the effect on NaOH-IP was smaller. In the allite soils, phosphorus accumulation is beneficial to the formation of NaOH-IP, but has little effect on the formation of HCl-P. For both application of chemical fertilizer and organic fertilizer, P accumulated in the soil was mainly inorganic, application of phosphorus had little contribution to formation of organic phosphorus. With the continuous accumulation of soil phosphorus, phosphorus accumulation effect on H₂O-P and NaHCO₃-IP is more obvious.