河北省果园氮素投入特点及其土壤氮素负荷分析

以河北省果园土壤地力调查、农户调查和统计数据为基础，采用氮盈余法从果树种类和区域角度分析了果园生产体系中的氮素输入输出特点及氮养分盈余状况。结果表明，河北果园平均化肥氮投入量为438.0 kg/hm2，主要品种为尿素和复合肥，有机肥氮为181.6 kg/hm2，以畜禽粪为主，其中禽粪占25.5%。京津东部区和冀中、南平原区的果园氮素投入、盈余量较高；葡萄园和桃园的氮素投入水平较高；果园氮素施用与养分盈余量之间存在极显著的正相关，过量施用氮肥是氮盈余量很高的主要原因。随着氮盈余量增加，果园土壤全氮呈增加趋势，而土壤C/N均呈下降趋势，氮素盈余对土壤全氮的影响大于对土壤有机质的影响。

Analysis of nitrogen input and soil nitrogen load in orchards of Hebei province

It is important to study and analyze the input and load characteristics of orchard nitrogen for orchard nitrogen nutrient management. Based on data collected from survey of orchard soil fertility, farmer interview and agricultural statistics database, the characteristics of N application and its surplus were studied among different fruit trees and regions through N balance method. The results showed that the average application rate of N fertilizer was 438.0 kg/ha, with common types being urea, and compound fertilizers. The N input rate through manure application was 181.6 kg/ha, using common animal waste and manures. However, poultry manure proportion accounted for 25.5% of organic manure. In different regions, the rates of N input, surplus in the orchards of the East Tangshan-Qinhuangdao region in Hebei and central-south districts of Hebei plain were relatively higher than other regions. It was found that peach and grape had higher rate of N fertilizer application compared with other fruit trees. Positive correlation was found between N surplus and applied N rate in the surveyed orchards. Excessive N fertilizer input led to the increase of N surplus and soil N load. Further, soil total nitrogen and the ratio of soil C/N increased with higher N surplus. The influence of nitrogen surplus on soil total nitrogen was higher than soil organic matter.