三种集约化种植体系氮素平衡及其对地下水硝酸盐含量的影响  

Nitrogen balance and its effects on nitrate-N concentration of groundwater in three intensive cropping systems of North China

作　　者：寇长林[1,2] 巨晓棠[1] 张福锁[1] 

机构地区：[1]中国农业大学资源与环境学院,教育部植物土壤相互作用重点实验室,农业部植物营养与养分循环重点实验室,北京100094 [2]河南省农业科学院土壤肥料研究所

出　　处：《应用生态学报》2005年第4期660-667,共8页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(30270787;30390080);国家"十五"科技攻关重大资助项目(2002BA516A02)

摘　　要：选取中国北方3种重要的集约化种植体系小麦 玉米轮作、大棚蔬菜和果园,研究了3种体系年度氮素输入输出关系、土壤硝酸盐的累积、不同体系地下水硝态氮含量的动态变化.结果表明,大棚蔬菜年度化肥氮、有机肥氮、灌水带入的氮和总氮输入量分别为135. 8、1881、4 0 2和36. 5 6kg·hm-2 ,分别为小麦 玉米田的2 5、37. 5、83. 8和5 . 8倍,为果园的2 .1、10 . 4、6. 8 2和4 . 2倍.不同系统降水输入的氮在14 2～18 9kg·hm-2 之间.3个体系氮输出量分别为2 80、32 9和12 1kg·hm-2 .氮素年度盈余分别为349、332. 7和74 .6kg·hm-2 .0～90cm土层硝态氮累积量分别为2 2. 1～2 .75、1173和6 13kg·hm-2 ,90～180cm土层硝态氮累积量分别为2 .13～2. 4 2、10 .32和976kg·hm-2 .在0～180cm剖面中,小麦玉米田各层土壤硝态氮处于相对均一分布,大棚蔬菜以表层最高,30cm以下各层也远高于大田,果园土壤硝态氮累积随土壤深度而增加.3种体系均表现出硝酸盐的明显淋洗.大棚蔬菜区浅井地下水硝态氮含量99%超过了10mg·L-1.而大棚深井和果园浅井超标率均为5 % ,小麦 玉米深井为1% .大棚蔬菜区地下水硝态氮含量与井深呈指数函数降低关系.Selecting three main intensive cropping systems of North China,i.e,wheat-maize rotation,plastic greenhouse vegetable,and apple orchard as test objectives,this paper studied their nitrogen (N) budget,soil nitrate-N accumulation,and year-round dynamics of groundwater nitrate-N concentration.The results showed that in plastic greenhouse vegetable cropping system,the annual N input from chemical fertilizers,manure,and irrigation was 1 358,1 881 and 402 kg·hm~ -2,being 2.5,37.5 and 83.8 folds of the corresponding items in wheat-maize cropping system,and 2.1,10.4 and 68.2 folds in orchard,respectively,and its total N input amounted to 3 656 kg·hm~ -2,being 5.8 times of the wheat-maize cropping system,and 4.2 times of the orchard.The wet deposition N in the three cropping systems ranged from 14.2 kg·hm~ -2 to 18.9 kg·hm~ -2.The N output by wheat-maize,greenhouse vegetable and orchard was 280,329 and 121 kg·hm~ -2,the N surplus was 349,3 327 and 746 kg·hm~ -2,and the remained nitrate-N after harvest amounted to 221～275,1 173 and 613 kg·hm~ -2 in 0～90 cm soil layer,and 213～242,1 032 and 976 kg·hm~ -2 in 90～180 cm soil layer,respectively.Crop field had a comparatively even distribution of nitrate N in its 0～180 cm soil profile,and a sharp increase of nitrate N throughout the soil profile were found in both greenhouse vegetable and orchard fields.There was an evident nitrate leaching in all three cropping systems.The groundwater in shallow well (<15 m) was severely contaminated in greenhouse vegetable area,with the nitrate-N concentration in 99% of the samples exceeding the maximum permissible limit for drinking water (10 mg·L~ -1),while 5% of the samples in deep well in vegetable area and in shallow well in orchard and 1% of the samples in deep well in wheat-maize field were exceeded the limit.The nitrate-N concentration exponentially decreased with well depth (m) in greenhouse vegetable area.

关 键 词：集约化种植体系 氮素平衡 土壤硝酸盐累积 地下水 硝酸盐污染 

分 类 号：X592[环境科学与工程—环境工程]