[Objective] The aim was to investigate effect of intercropping and nitrogen regulation on nitrate and apparent loss of nitrogen, providing theoretical references for reasonable fertilization and pollution reduction. [...[Objective] The aim was to investigate effect of intercropping and nitrogen regulation on nitrate and apparent loss of nitrogen, providing theoretical references for reasonable fertilization and pollution reduction. [Method] In the research, deeprooted eggplants and shallow-rooted scallions were intercropped with nitrogen regulat- ed to study on effect of the cropping system on temporal and spatial changes of ni- trate nitrogen and apparent loss of nitrogen. [Result] When the fertilizers were re- duced, contents of nitrate were less in intercropped field than that in mono-cropped one, indicating that eluviation of nitrate would be blocked and nitrate accumulation would be lowered effectively by intercropped eggplants and scallions. With intercrop- ping adopted, the reduced fertilizers would lower nitrate content in soil, deep soil in particular, and nitrate was significantly lower than that fertilized with conventional quantity during vegetable growth period. In addition, nitrate accumulation in soil profiles was also significantly shorter in field applied with reduced fertilizers than that with conventional one. It was shown that intercropping and fertilizer reduction would both cut apparent loss of nitrate down in varying degrees. [Conclusion] The research lays basis for high production of vegetables, reasonable fertilization and pollution reduction.展开更多
An experiment upon an agri-silvicultural system involving Willow （Salix alba） tree, Kale （Brassica oleracea var. acephala） and Knol khol （Brassica oleracea var. caularapa） was laid in randomized block designed a...An experiment upon an agri-silvicultural system involving Willow （Salix alba） tree, Kale （Brassica oleracea var. acephala） and Knol khol （Brassica oleracea var. caularapa） was laid in randomized block designed at farmers＇ willow field at Shalimar near Sher-e- Kashmir University of Agricultural Sciences and Technology of Kashmir, Srinagar India during 2005 and 2006. The main plot was divided into sub-spots with 8 m × 2 m in size each in which four two-year-old willow （Salix alba） trees were at a spacing of 2 m ×2 m in a sub-spot. The intercrops were maintained at recommended spacing and supplied with recommended doses of fertilizers. The benefit-cost ratio in willow plantation intercropped with vegetable crops of Kale and Knol Khol was analyzed and compared with the benefit-cost ratio of sole willow tree forestry. The results showed that every rupee invested in plantation of agri-silvicultural system generates benefit-cost ratio of 2.78 and 2.79 in case of Willow intercropping with Kale and Willow with Knol khol, respectively, while as for sole crop of willows benefit-cost ratio was calculated to be 2.66. These results provided circumstantial evidence in favour of adopting agroforestry involving willow instead of Sole tree forestry.展开更多
基金Supported by"Research on Nitrate Nitrogen Eluviation and Water Adjustment through Intercropping of Vegetables with Different Root Lengths"of Beijing Science and Technology Star Plan(B)(2007B045)"Effects of Fertilizer Sources on Heavy Metals in Soils and Vegetable Quality"of Foundation for Distinguished Scholars in Beijing(D)(2010D002020000004)"Research on Mutation Rules of Key Indices in SoilEnvironment for Tomato with High-production"of Foundation for Youths of Beijing Academy of Agricultural and Forestry Sciences(QN201103)~~
文摘[Objective] The aim was to investigate effect of intercropping and nitrogen regulation on nitrate and apparent loss of nitrogen, providing theoretical references for reasonable fertilization and pollution reduction. [Method] In the research, deeprooted eggplants and shallow-rooted scallions were intercropped with nitrogen regulat- ed to study on effect of the cropping system on temporal and spatial changes of ni- trate nitrogen and apparent loss of nitrogen. [Result] When the fertilizers were re- duced, contents of nitrate were less in intercropped field than that in mono-cropped one, indicating that eluviation of nitrate would be blocked and nitrate accumulation would be lowered effectively by intercropped eggplants and scallions. With intercrop- ping adopted, the reduced fertilizers would lower nitrate content in soil, deep soil in particular, and nitrate was significantly lower than that fertilized with conventional quantity during vegetable growth period. In addition, nitrate accumulation in soil profiles was also significantly shorter in field applied with reduced fertilizers than that with conventional one. It was shown that intercropping and fertilizer reduction would both cut apparent loss of nitrate down in varying degrees. [Conclusion] The research lays basis for high production of vegetables, reasonable fertilization and pollution reduction.
文摘An experiment upon an agri-silvicultural system involving Willow （Salix alba） tree, Kale （Brassica oleracea var. acephala） and Knol khol （Brassica oleracea var. caularapa） was laid in randomized block designed at farmers＇ willow field at Shalimar near Sher-e- Kashmir University of Agricultural Sciences and Technology of Kashmir, Srinagar India during 2005 and 2006. The main plot was divided into sub-spots with 8 m × 2 m in size each in which four two-year-old willow （Salix alba） trees were at a spacing of 2 m ×2 m in a sub-spot. The intercrops were maintained at recommended spacing and supplied with recommended doses of fertilizers. The benefit-cost ratio in willow plantation intercropped with vegetable crops of Kale and Knol Khol was analyzed and compared with the benefit-cost ratio of sole willow tree forestry. The results showed that every rupee invested in plantation of agri-silvicultural system generates benefit-cost ratio of 2.78 and 2.79 in case of Willow intercropping with Kale and Willow with Knol khol, respectively, while as for sole crop of willows benefit-cost ratio was calculated to be 2.66. These results provided circumstantial evidence in favour of adopting agroforestry involving willow instead of Sole tree forestry.
