氮肥优化减施对土壤-莴苣系统氮磷平衡及产量效益的影响  

Yield and nutrient balance of lettuce as influenced by reduced and optimized nitrogen application

作　　者：全智[1,2] 秦红灵[1] 李明德[3] 朱亦君[1] 刘新亮[1] 魏文学[1] 吴金水[1] 

机构地区：[1]中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室,长沙410125 [2]中国科学院研究生院,北京100049 [3]湖南省农业科学院土壤肥料研究所,长沙410125

出　　处：《中国生态农业学报》2011年第4期738-744,共7页Chinese Journal of Eco-Agriculture

基　　金：中国科学院创新团队国际合作伙伴计划项目(KZCX2-YW-T07);中国科学院知识创新工程重要方向项目(KZCX2-YW-437);国家自然科学基金项目(40801098)资助

摘　　要：采用田间小区试验,研究了氮肥减施20%(80%N)与施肥优化[施缓释尿素并减氮20%(80%N+CRU)、氮肥减施20%并添加脲酶抑制剂/硝化抑制剂(80%N+QD)、氮肥减施20%并添加土壤调理剂(80%N+SC)]对土壤-莴苣系统氮磷平衡以及产量效益的影响。结果表明:3种优化减氮处理均在一定程度上降低了菜地土壤NO3--N(硝态氮)、Olsen-P(有效磷)含量及硝化率水平,从而降低了氮磷流失进入环境的风险;同时减氮处理还提高了土壤氮素的利用效率,增加了蔬菜鲜样产量及菜农实际收入,效益明显。其中,80%N+CRU处理降低土壤NO3--N和Olsen-P含量最为明显,但该处理植株可食部分容易累积硝酸盐,收获时莴苣茎硝酸盐含量显著高于常规施肥处理(CF)和《农产品安全质量无公害蔬菜安全要求》(GB18406.1—2001)(P<0.05);80%N+QD处理对各时期土壤Olsen-P及蔬菜可食部分硝酸盐含量影响较小,却显著降低了菜地土壤的硝化率水平(P<0.05),从而提高了养分利用效率,同时与CF处理相比,该处理较大幅度增加了莴苣鲜样产量(茎21.7%,叶7.6%)、总收入(13.0%)、实际收入(14.0%)和产投比(14.2%),是最佳减氮优化处理。试验地80%N+SC处理效果不稳定,与常规施肥差异不显著。兼顾经济、食用风险、生态环境等效益,建议在高肥力菜地土壤中,氮肥减量与脲酶抑制剂、硝化抑制剂配合施用。Environment and health quality of vegetable are closely related with food quality and human health.Most farmers use excessive chemical fertilizers to maximize yield.This practice,along with high irrigation and multiple cropping,results in soil degra-dation,nitrogen（N）/phosphorus（P） loss,and other severe environmental issues.A field experiment was carried out in a vegetable field of suburban Changsha City to determine the effects of reduced and optimized application of N fertilizer on soil nutrient balance and yield of lettuce.N was reduced by 20% under optimized fertilization strategies of slow-release urea（80%N＋CRU）,urease/nitrification inhibitor（80%N＋QD） and soil conditioner（80%N＋SC）.The results showed that the three optimized strategies reduced soil NO3-N,Olsen-P content and nitrification rate.This reduced N/P loss into the environment and enhanced nitrogen use efficiency.It also in-creased lettuce biomass and farmers＇ real income,with obvious economic and environmental benefits.The 80%N＋CRU strategy sig-nificantly reduced soil NO3-N,Olsen-P contents and the loss of N and P into the environment.Compared with conventional fertilizer treatment（CF） and national standard（GB18406.1-2001）（P0.05）,however,it increased nitrate in the stem of lettuce at harvest.The 80%N＋QD strategy had no significance effects on soil Olsen-P and nitrate in edible parts of lettuce.It,however,significantly reduced soil nitrification rate（P0.05） and increased biomass yield by 21.7% for stem,7.6% for leaf;and increased total revenue by 13.0%,farmers＇ real income by 14.0%,and output/input ratio by 14.2%.The 80%N＋QD strategy was therefore recommended as the optimal strategy.Although the effect of 80%N＋SC treatment was not completely satisfactory,it improved the nutrient use efficiency.On ac-counts of comprehensive production effects,health safety and ecological benefits,it was suggested that the application of urease/nitrification inhibitors with reduced nitrogen fertilizer should be adopt

关 键 词：氮肥减施 缓释尿素 脲酶/硝化抑制剂 土壤调理剂 硝态氮 有效磷 硝酸盐 

分 类 号：S147.5[农业科学—肥料学] S151.5[农业科学—农业基础科学]