摘要
为探讨小麦/玉米/大豆套作对氮素营养的种间促进机制,采用叶片15N富积标记法研究了小麦/玉米/大豆(A1)和小麦/玉米/甘薯(A2)2种套作系统中不同施氮水平下的土壤培肥效果和氮素转移规律。结果表明,施氮可以提高小麦、玉米的土壤总氮含量,以施纯氮150～300kghm-2处理最高;大豆较甘薯更有利于保持土壤肥力,施氮0、150、300和450kghm-2水平下种植大豆后的土壤总氮含量比种植大豆前(小麦收获后)高38.6%、20.2%、9.4%和16.7%,而种植甘薯则降低总氮含量3.1%、1.8%、14.0%和3.8%。A1系统中小麦和玉米季土壤中NO3-N含量低于A2系统,且随施氮量的增加而增加;大豆季土壤中NO3-N含量高于甘薯季。A1和A2系统均存在15N的双向转移,15N转移量随施氮量的增加而降低,且A1的15N净转移量和转移强度高于A2;A1系统中小麦、玉米和大豆的15N净转移量比A2系统的15N净转移量分别高3.3%～12.1%、27.0%～166.2%和26.2%～78.7%。玉米与小麦之间的15N净转移方向为从玉米向小麦,玉米与大豆之间的15N净转移方向为从大豆向玉米,玉米与甘薯之间的15N净转移方向为从玉米向甘薯。
The aim of this study was to characterize nitrogen transfer in the relay strip intercropping system of wheat/maize/soybean,and to investigate the N promotion mechanism.A pot experiment was conducted to determine the soil N content and transfer in the relay strip intercropping of wheat/maize/soybean and wheat/maize/sweet potato using the direct 15N foliar feeding technique.The N application rates were 0,150,300,and 450 kg ha 1.The results showed that N application increased the soil total N contents in wheat and maize seasons.The total N content of soil reduced when N applied in an excessive rate,and the highest values of soil total N content appeared at the N rate of 150-300 kg ha 1.Moreover,the soil total N contents in wheat and maize seasons in the relay strip intercropping of wheat/maize/soybean were higher than those in the wheat/maize/sweet potato system.After soybean planted in the relay strip intercropping,the soil total N contents increased by 38.6%,20.2%,9.4%,and 16.7% at applied N rates of 0,150,300,and 450 kg ha 1,respectively.Whereas after sweet potato planted,they were reduced by 3.1%,1.8%,14.0%,and 3.8%,respectively.Therefore,the soybean season was beneficial to maintaining soil fertility.The soil NO3-N contents in wheat and maize seasons increased with the raising of N application rate,and the values in wheat/maize/soybean system were lower than those in wheat/maize/sweet potato system.The soil NO3-N contents in soybean season were higher than those in sweet potato season.Bi-directional 15N transfer existed in both relay systems.The amount of transferred 15N reduced with the increasing of N application rate.The strength and amount of net transferred 15N in the wheat/maize/soybean system were higher than those in the wheat/maize/sweet potato system.The amounts of net transferred 15N in wheat,maize,and soybean in the wheat/maize/soybean system increased by 3.3-12.1%,27.0-166.2%,and 26.2-78.7% com-pared to the corresponding crops in the wheat/maize/sweet potato system,respectively.Moreover,the directions of the 15N transfer were evident,which were from maize to wheat,from soybean to maize,and from maize to sweet potato.
出处
《作物学报》
CAS
CSCD
北大核心
2012年第1期148-158,共11页
Acta Agronomica Sinica
基金
国家重点基础研究发展计划(973计划)项目(2011CB100400)
国家大豆产业技术体系专项(CARS-04-PS19)资助
关键词
小麦/玉米/大豆
套作
土壤氮素
氮素转移
15N富积标记法
Wheat/maize/soybean system
Replay strip intercropping
Soil nitrogen
N transfer
15N foliar feeding
