Legume Productivity and Soil Nitrogen Dynamics in Lowland Rice-Based Cropping Systems
Legume Productivity and Soil Nitrogen Dynamics in Lowland Rice-Based Cropping Systems
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低地稻作系统中豆类生产力和土壤氮动态
DOI：
10.2136/sssaj1996.03615995006000010030x
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发表时间：
1996
影响因子：
2.9
通讯作者：
P. Dart
中科院分区：
文献类型：
--
作者：
J. Ladha;D. K. Kundu;M. A. Coppenolle;V. Carangal;M. Peoples;P. Dart
水稻（Oryza sativa L.）在潮湿季节（WS）之前是干燥季节（DS）休闲，通常在潮湿的低地实施，通过NO淋溶和反硝化作用导致大量的N损失。绿肥豆类作为非捕捞作物在经济上对农民没有吸引力。在为期2年的研究中，我们（i）评估了一种谷物和四种饲料豆类（木豆[Cajanus cajan（L.）Millsp.]，猪屎豆（Crotalaria juncea L.），阴蒂（Clitoria ternatea L.），德斯芒[Desmanthus virgatus（L.）Willd.]，和siratro [Macroptilium atropurpureum（Mocino & Sesse ex DC.）城市]）生长在DS，（ii）研究NO-N和NH-N在土壤中的动态（一个典型的Tropaquept），和（iii）评价豆类残留物作为氮源的后续水稻。硝态氮是占主导地位的30厘米表土，并根据豆类杂草休闲相比。豆科植物地上生物量为4.9 ~ 9.1t/ha，积累氮132 ~ 306 kg/ha，其中67 ~ 81%来自固氮。收获后，2.9至5.2吨公顷的残留物含有81至162公斤氮公顷返回到土壤。洪水后3至4周，豆类处理地块有多达33至40公斤的矿物氮公顷在表土相比，10至13公斤氮公顷杂草休耕地块。秸秆还田显著提高了水稻产量和氮素吸收量。水稻对残留氮的回收率为15 ~ 31%。休耕地块需要25至50公斤的肥料氮公顷，以产生可比的植物生长反应后获得的豆类。地下残留的豆科植物显然贡献了13至37公斤N公顷的水稻。这种DS豆类，提高农业生产力，以及增加土壤肥力，可能会确保生产的可持续性，在干旱的低地。
Rice (Oryza sativa L.) in wet season (WS) preceded by a dry season (DS) fallow, commonly practiced in rainfed lowlands, causes large losses of N through NO leaching and denitrification. The green-manure legumes as NO catch crops is economically unattractive to farmers. In a 2-yr study, we (i) assessed productivity of one grain and four forage legumes (pigeonpea [Cajanus cajan (L.) Millsp.], crotalaria (Crotalaria juncea L.), clitoria (Clitoria ternatea L.), desmanthus [Desmanthus virgatus (L.) Willd.], and siratro [Macroptilium atropurpureum (Mocino & Sesse ex DC.) Urban]) grown in the DS, (ii) examined NO-N and NH-N dynamics in soil (a Typic Tropaquept), and (iii) evaluated legume residues as a N source for succeeding rice. Nitrate-N was dominant in the 30-cm topsoil and was higher under legumes compared with weedy fallow. The legumes produced 4.9 to 9.1 t aboveground biomass ha, accumulated 132 to 306 kg N ha of which 67 to 81% was derived from N fixation. After harvests, 2.9 to 5.2 t ha of residues containing 81 to 162 kg N ha were returned to soil. By 3 to 4 wk after flooding, legume-treated plots had as much as 33 to 40 kg mineral N ha in topsoil compared with 10 to 13 kg N ha in weedy fallowed plots. Residues significantly increased rice yield and N uptake. Rice recovered 15 to 31% of the residue N. Fallow plots required 25 to 50 kg fertilizer N ha to produce comparable plant growth responses to that obtained after the legumes. Belowground residues of the legumes apparently contributed 13 to 37 kg N ha to rice. Such DS legumes that improve farm productivity as well as increase soil fertility might ensure sustainability of production in rainfed lowlands.