中国主要粮食作物磷肥偏生产力时空演变特征及驱动因素

Spatial-temporal evolution characteristics and driving factors of partial phosphorus productivity in major grain crops in China

【目的】中国旱地及水旱轮作区经过长久以来多种施肥模式的调整,各区域土壤磷素状况变异较大,探讨各区域土壤磷肥盈亏量和作物磷肥偏生产力的时空演变及主要驱动因素,为维持土壤磷素表观平衡和磷肥的科学管理提供理论指导。【方法】以农业农村部1988—2019年在全国旱地及水旱轮作区开展的长期监测数据库为基础,分析东北、华北、长江中游、长三角、西南和西北6个区域(共829个监测点)三大粮食作物(小麦、玉米和水稻)磷肥施用量、磷肥偏生产力和土壤磷素盈亏量的时空变化,确定各区域不同作物的适宜磷肥施用量。【结果】全国旱地及水旱轮作区小麦、玉米、水稻季磷肥施用量和磷肥偏生产力平均分别为137.7、109.2、75.13 kg/hm^(2)和61.99、130.1、158.9 kg/kg,其中西北区小麦、玉米季磷肥施用量和磷素盈余量均为最高,分别为213.7、184.0 kg/hm^(2)和157.9、51.55 kg/hm^(2),磷素盈余量分别占磷素施用量的73.9%和28.0%。东北、华北和长三角区玉米季土壤处于磷素亏缺状态,亏缺量分别为25.29、11.38和14.57 kg/hm^(2),长三角和西南区水稻季土壤处于磷平衡状态。近30年,东北、华北和长江中游作物磷肥偏生产力随施肥年限的延长呈显著增加趋势,并在2013年后趋于稳定,长三角和西南作物磷肥偏生产力呈先降低后增加的趋势。西北区磷肥偏生产力则在施肥30年间持续升高。磷素盈余量的区域差异和磷肥偏生产力的时空变异主要受到磷肥施用量和作物类别的影响,此外,土壤类型、有机质含量和种植制度分别是东北、长江中游和西北磷素盈余量和磷肥偏生产力的主要影响因素。【结论】各区域小麦季过量磷肥投入均造成大量磷素盈余,玉米和水稻季全国平均处于磷平衡状态,磷素盈余和磷肥偏生产力的时间变化及驱动因素存在显著的区域性差异。综合考虑磷肥偏生产力和各区域的驱动因素,建议华北、长江中游、长三角、西南和西北小麦季推荐磷肥施用量分别为64.42、37.59、60.11、35.22和53.55 kg/hm^(2);东北、华北、长江中游、长三角、西南和西北玉米季磷肥推荐施用量分别为129.5、97.11、83.85、80.60、80.09和131.9 kg/hm^(2);长江中游、长三角和西南水旱轮作区水稻季磷肥推荐施用量分别为62.12、76.32和64.03 kg/hm^(2)。

【Objectives】In the last 30 years,there are various fertilization regimes in upland and paddy-upland rotation systems in China,and the variation of soil phosphorus(P) status in different regions was great.The objective of this study was to analyze the spatio-temporal characteristics and driving factors of P surplus and partial factor productivity of P(PFPP) in each region,and to provide theoretical guidance for scientific management of P fertilizer.【Methods】Based on the long-term monitoring database(1988 to 2019),data were cited from a total of 829 upland and paddy-upland rotation monitoring sites for comparison and summarization in six regions(i.e.Northeast of China(NE),North of China(NC),Yangtze River Delta(YRD),Middle Reaches of the Yangtze River(MYR),Northwest of China(NW) and Southwest of China(SW)).The P fertilizer application rate,PFPP,P balance and the main driving factors of PFPP and P balance were analyzed,and the recommended P application rate in each region was further determined.【Results】The average application rate of P fertilizer and PFPP were 137.7,109.2,75.13 kg/hm^(2) and 61.99,130.1,158.9 kg/kg in wheat,maize and rice cropping system in upland and paddy-upland rotation in China,respectively.The application rate of P fertilizer(213.7 and 184.0 kg/hm^(2)) and P surplus(157.9 and 51.55 kg/hm^(2)) in wheat and maize in NW were the highest,and the P surplus accounted for 73.9% and 28.0% of the P application rate,respectively.In the maize season,the value of P balance in NE,NC and YRD were deficient,and the amount of deficiency were 25.29,11.38 and 14.57 kg/hm2,respectively.In the rice season,the application rates of P fertilizer were consistent with P output in YRD and SW.The PFPP in NE,NC and MYR increased significantly with the cultivation years from 1988 to 2012,and began to be stable after 2013.In the YRD and SW,the PFPP decreased at first and increased later,and the turning points were in 2002 and 2007,respectively.In NW,the PFPP increased continuously after 30 years of fertilization.The soil type,organic matter content and cropping system were the main influencing factors of P surplus and PFPP in NE,MYR,and NW,respectively.The regional differences of P surplus and PFPP were mainly affected by the application rate of P fertilizer and crop type.【Conclusions】Excessive P application in wheat season has resulted in a large amount of P surplus in each region,and the application rates of P fertilizer were consistent with P output in maize and rice season in China.In addition,there were significant regional differences in the temporal variation and driving factors of phosphorus balance and PFPP.Considering the PFPP and the driving factors of each region,the recommended P fertilizer application rates in NC,MYR,YRD,SW and NW in wheat season were 64.42,37.59,60.11,35.22 and 53.55 kg/hm^(2),respectively.In NE,NC,MYR,YRD,SW and NW,the recommended rates of P fertilizer in maize season were 129.5,97.11,83.85,80.60,80.09 and 131.9 kg/hm^(2),respectively.While in MYR,YRD and SW,the recommended P application rates were 62.12,76.32 and 64.03 kg/hm^(2),respectively.