摘要
氮素损失对农业生产造成的影响已成为当前研究的热点,模型是对氮素损失影响评价及定量化研究的有效手段。利用华北典型农田冬小麦-夏玉米轮作种植模式的作物产量、氮素淋失量等田间观测数据对DNDC模型进行了验证,并采用验证后的DNDC模型对该种植模式的氮素损失进行了定量评价,提出了综合考虑作物产量、氮素淋失量、N2O排放量以及NH3挥发损失的综合调控途径。结果表明,DNDC模型较好地模拟了冬小麦-夏玉米轮作系统作物的产量、氮素淋失的动态变化规律,以及土壤中NO3--N和NH4+-N的残留量,说明DNDC已具备模拟农田生态系统中土壤氮素生物地球化学过程的能力。模型模拟结果表明,在传统农业管理措施下,氮素通过淋失、N2O排放以及NH3挥发损失的量分别达到49.4 kg(N).hm-2.a-1、17.71kg(N).hm-2.a-1和144.8 kg(N).hm-2.a-1。综合考虑氮素损失途径,提出了适合当地农业生产条件的最优化管理措施,即减小当前常规施氮量到340 kg(N).hm-2.a-1,提高玉米秸秆还田率到100%,并保持灌溉量不变。相比常规管理措施,最优化管理措施氮素淋失量为14.1 kg(N).hm-2.a-1,降低71.5%,N2O排放量为14.91kg(N).hm-2.a-1,降低15.8%,NH3挥发损失量为117.2 kg(N).hm-2.a-1,降低19.1%,而对作物产量基本不造成明显影响。该评价结果可直接用于农业生产实践。
Modern agricultural practices are strongly linked to fertilizer application for maintaining optimum yields.However,inefficient fertilizer use has led to a significant portion of the nitrogen（N） applied to farm fields reaching surface or underground water and atmosphere systems.The scientists from all over the world are committing themselves on improving the utilization of N fertilizer and decreasing the N leaching and N2O emissions from farmland.This paper aims to provide comprehensive management alternatives which can accommodate the needs to maintain high crop yields,to conserve diminishing natural resources,and to minimize environmental damage.The field experiment observations of N leaching,crop yields,etc.,in conjunction with the local climate,soil and management information from winter wheat-summer maize rotation field,were utilized to test a process based model,Denitrification-Decomposition or DNDC,for its applicability for the cropping system,and then used the validated model to quantitatively evaluate the N loss in winter wheat and summer maize rotation croplands of North China.The optimum management practices were proposed with comprehensively consideration of the crop yield,N leaching,N2O emissions and NH3 volatilization.The results showed that the DNDC model could simulate the change of N leaching and soil residual NO3-N,NH4＋-N well in winter wheat-summer maize rotation field.Moreover,the model generally had acceptable performances in the model simulations for the yield of winter wheat and summer maize.According to the model＇s simulation,the amount of N loss through leaching,N2O emissions and NH3 volatilization were 49.4 kg（N）·hm^-2·a^-1,17.71 kg（N）·hm^-2·a^-1 and 144.8 kg（N）·hm^-2·a^-1,respectively,in the management of traditional practices.Comprehensively analysis of the nitrogen losses,the authors put forward some optimum management practices for its applicability for local agricultural production conditions,which were to reduce 40% of conventional nitrogen fertilizer to 34
出处
《中国生态农业学报》
CAS
CSCD
北大核心
2012年第4期414-421,共8页
Chinese Journal of Eco-Agriculture
基金
公益性行业(农业)科研专项(201103039)资助
