Characteristics of soil phosphorus input and phosphorus load risk in major orchards region of Hebei

Chinese. 【目的】作为果树生长发育必需的大量营养元素，磷素对生态环境和可持续发展同样具有重要影响。研究果园磷素投入特点及分析磷素负荷特征对加强果园磷素管理具有重要意义。【方法】以河北省主要果园土壤磷素分析、农户投入调查等统计数据为基础，采用盈余法从区域角度分析果园生产体系中的磷素输入输出特点及磷素盈余状况，分析土壤磷负荷风险。【结果】果园磷肥投入量为230.6 kg P2O5・ha. 1，主要来源于普钙、二铵和三元复合肥；通过有机肥投入的磷素水平为128.1 kg P2O5・ha. 1，主要来源于畜禽粪便，其中畜粪占35.8%，禽粪占25.5%。果园施磷水平以冀东北区和冀中南平原区较高，分别为378.5、195.5 kg P2O5・ha. 1。80%的果园磷素样本处于盈余，总体平均盈余量为269.5 kg P2O5・ha. 1，最大盈余量超过1 900 kg P2O5・ha. 1。施磷过量造成土壤有效磷积累，供磷丰富的果园土壤上磷肥过量的样本占88.5%。土壤磷环境负荷以冀东北区和冀中南平原区的果园较高，总体上果园土壤有效磷高于土壤磷环境风险阈值的样本占33.6%。【结论】河北果园磷素的高量投入给土壤环境带来较大的磷素负荷，这对土壤环境和周围水体造成很大威胁。

English. [Objective] As one of the necessary macronutrients for fruit tree growth, phosphorus affects ecological environment and sustainable development. It＇s very important to study the characteristics of phosphorus input and phosphorus load in orchard in order to improve phosphorus nutrient management. [Method] Based on the data collection through soil fertility survey of orchard, farmer interviewing and agricultural statistics database, the characteristics of P application, surplus and P load were studied using nutrient balance method at different regions in Hebei. [Result] The average application rate of P fertilizer was 230.6 kg PaO5・ha. 1, with common types of calcium superphosphate, diamine phosphate and compound fertilizers; The P input rate through manure application was 128.1 kg P2O5・ha. 1, with common animal waste and manures. The proportions of livestock manure and fowl manure in organic manure species accounted for 35.8% and 25.5%, respectively. The P fertilizer applied rate in the orchards in northeast and central-south districts of Hebei plain were 378.5 and 195.5 kg P2O5・ha. 1, respectively, and were relatively higher than the other region. P surplus was investigated in the 80% of surveyed orchards, with the average amount of 269.5 kg P2O5・ha. 1, and highest amount of 1 900 kg P2O5・ha. 1. High rate of P supply caused soil P accumulation in orchard, however, P over-fertilization were investigated on 88.5% of orchards with excessive soil P accumulation. P surplus rate and soil environmental P load in these orchards at the northeast and central-south districts were higher than the other regions of Hebei plain. Soil available P level in 33.6% in the surveyed orchard had been over the critical risk level of P.[ Conclusion] High P input in the orchards of some regions led to very high rate of P load to soil environment, and this will increase high environmental risk in Hebei.