陕西关中冬小麦-夏玉米种植区塿土无机磷形态及其有效性

为了探明关中冬小麦-夏玉米产区典型土壤无机磷组分含量及其有效性,实现减磷增效、合理施用磷肥,提高土地生产力。于2018年采集陕西省关中平原冬小麦-夏玉米种植区塿土耕层(0～20 cm)样品,采用蒋柏藩与顾益初改进的无机磷分级法测定各无机磷组分含量,并结合相关分析与通径分析,比较各无机磷组分对有效磷的贡献。结果表明:塿土总无机磷含量为585.4～1513.8 mg/kg,各形态含量组成大小依次为Ca_(10)-P(36.8%～82.9%)Ca_8-P(5.0%～30.7%)O-P(6.4%～17.5%)Al-P(1.0%～16.6%)Fe-P(1.8%～17.2%)Ca_2-P(0.1%～4.8%);相关分析表明,各无机磷形态和有效磷的相关性大小依次为Ca_2-P(0.912)Ca_8-P(0.598)Al-P(0.569)Fe-P(0.531)O-P(0.426)Ca_(10)-P(0.138),仅Ca_(10)-P和有效磷不具有相关关系,其余无机磷形态和有效磷均有极显著相关关系;通径分析表明,各无机磷形态对有效磷的贡献大小依次为Ca_2-P(0.771)Ca_8-P(0.155)Fe-P(0.107)O-P(0.042)Al-P(0.010)Ca_(10)-P(-0.068)。其次,逐步回归分析结果也证实Ca_2-P、Ca_8-P和Fe-P是塿土有效磷的主要磷源,Al-P和O-P是缓效磷源,Ca_(10)-P则难以被作物吸收利用。

Inorganic Phosphorus Forms and Availability of Tier Soil in Winter Wheat- Summer Maize Planting Area in Guanzhong of Shaanxi Province

The content of inorganic phosphorus fractions and their contribution to available phosphorus were investigated in typical soils of winter wheat-summer maize production areas of Guanzhong.The aim of this study is to provide a reasonable basis for reducing the amount of phosphorus fertilizer,enhancing the efficiency of phosphorus use,and for improving land productivity.In 2018, the cultivated soil samples were collected from the tier soil of winter wheat-summer maize planting areas in Guanzhong Plain.The inorganic phosphorus classification method improved by Jiang and Gu was used to determine the content of inorganic phosphorus components in soil samples.Additionally, the contribution of various inorganic phosphorus forms to available phosphorus (Olsen-P) was evaluated by introducing correlation analysis and path analysis.The results showed that the range of total inorganic phosphorus content was within 585.4-1 513.8 mg/kg,and the content of each form was in order of Ca10-P(36.8%-82.9%)>Ca8-P(5.0%-30.7%)>O-P(6.4%-17.5%)>Al-P(1.0%-16.6%)>Fe-P(1.9%-17.2%)>Ca2-P(0.1%-4.8%);the results of correlation analysis indicated that the correlation between each inorganic phosphorus form and available phosphorus was in sequence of Ca2-P(0.912)>Ca8-P(0.598)>Al-P(0.569)>Fe-P(0.531)>O-P(0.426)>Ca10-P(0.138), Ca10-P had no correlation with available phosphorus, and the remaining inorganic phosphorus forms had significant correlation with available phosphorus.Furthermore, path analysis revealed that the contribution of each inorganic phosphorus form to available phosphorus was in order of Ca2-P(0.771)>Ca8-P (0.155)>Fe-P(0.107)>O-P(0.042)>Al-P(0.010)>Ca10-P(-0.068). The stepwise regression analysis also demonstrated that Ca2-P, Ca8-P and Fe-P were the main sources of available phosphorus, Al-P and O-P were slow-release phosphorus sources, while Ca10-P was difficult to be absorbed by plants.