【作者】 刘常珍；

【导师】 赵言文； 胡正义； 卞新民；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2004， 硕士

【摘要】 土壤NO₃^-淋失不但导致氮利用率低，也是地表水和地下水主要污染源之一。本研究通过室内土壤培养和温室盆栽淋洗试验，对元素硫（S⁰）、双氰胺（DCD）及其组合对不同性质的两种蔬菜地土壤NH₄⁺硝化，NO₃淋溶损失和土壤无机氮含量、pH的影响及其作用机理进行了研究。 土壤培养试验结果表明： 1、S⁰、DCD及其组合施入土壤可抑制NH₄⁺向NO₃^-的转化，降低土壤NO₃^- -N水平，使土壤内NH₄⁺ -N长时间保持较高水平。经过72d的培养，各处理氮素硝化抑制率以DCD+S⁰、DCD+Na₂S₂O₃和DCD处理最高、持续时间最长，由大到下依次为：DCD+S⁰、DCD+Na₂S₂O₃、DCD，且硝化抑制时间在施用碳酸氢铵下比施用尿素下（48d）多24d，为72d。其次为S⁰和Na₂S₂O₃处理分别显著抑制NH₄⁺氧化达32d和16d。 2、S⁰，DCD和Na₂S₂O₃三者平均作用效果比较，以DCD效果最好。DCD作用下土壤NH₄⁺-N浓度总平均比对照高27.7～31.3mg/kg，分别是S⁰和Na₂S₂O₃作用下的2.6～2.7倍和3.1～3.9倍；NO₃^- -N抑制率总平均为27.2～28.2％，分别是S⁰和Na₂S₂O₃作用下的2.5～2.9倍和2.1～4.0倍；无机氮总平均抑制率为10.9～11.8％，分别是S⁰和Na₂S₂O₃总平均的1.7～2.3倍和2.2～4.5倍。且S⁰、Na₂S₂O₃与DCD配合施用还可增强DCD作用效果。在S⁰、Na₂S₂O₃与DCD配合施用DCD作用下其土壤NO₃^- -N抑制率分别比单施DCD作用下高3.5～4.8％和10.4～13.7％；无机氮抑制率分别比单施DCD作用下高3.1～3.8％和30.6～37.5％。S⁰施入土壤可增强DCD作用效果其作用机理为S⁰在土壤中氧化形成的S₂O₃^2-具有抑制DCD分解的作用。 盆栽淋洗试验结果表明： 1、元素硫、双氰胺及其组合施入土壤可有效减少氮素的淋失，增加土壤无机氮含量，且作用效果因土壤性质不同而有差异，潮土下作用效果要好于黄潮土。供试土壤为黄潮土时，各处理淋失的氮素和土壤内残留的氮素基本全为NO₃^- -N。以S⁰和Na₂S₂O₃抑制效果较好，而DCD效果则不显著。与对照处理相比，施用尿素和碳酸氢铵下，S⁰处理NO₃^--N淋失量分别低40.38％和9.96％；Na₂S₂O₃处理分别低59.11％和元幸硫、双氛胺及其组合对蔬菜地土壤脸一N淋失的影响及机理研究10.52%.试脸结束后，土壤无机氮量以s0、s0+DcD和DcD处理较高. 2、供试土壤为潮土时，以so+DcD和s0处理氮素淋失最少，土壤残留无机氮最高，且以按态氮为主.与cK相比，s0+D cD和s0处理，在施用尿素下NO3一累积淋失量分别低86%⁸9%和86%一87%，土壤残留的无机氮量分别高68.8%一71.6%和75.6%一96.钱;施用破酸氮按下，NO3一淋失童则分别低83%一86%和83%，土壤残留的无机氮童分别高79.9%一85.4%和74.7%一82.6%.NaZsZO3、N匆凡03+DCD和DCD处理也发现类似结果.可见，s0施入土壤可抑制土壤峭化其作用机理为s0在土坡中氧化形成的520尹具有抑制氮素峭化的作用. 3、s0、ocD和NaZsZO3三者平均作用效果比较.黄潮土为供试土壤的淋洗试脸中，以NaZSZ伪作用效果最好，其次为50.潮土为供试土壤的淋洗试脸中，以s0作用效果最好，其次为Na2s203.s0、 NaZsZ伪与DcD配合还可增强DcD的峭化抑制性.且s0和NaZsZ伪平均作用效果在施用尿素下要强于施用破酸氮按，其机理为s0在土壤中氧化形成的52伪2-和s’O扩一具有抑制膝醉活性的作用. 4、元素硫、双氛胺及其组合可增加跪莱产量，减少硫菜峭酸盐含量.青菜生物童在施用尿素下，以DcD和50+neD处理较高，分别较对照处理高24 .6%和15.8%;施用破酸氛按下，以so+DcD和S0处理较高，分别较对照处理高24.5%和14.8%.而青莱峭酸盆含量则以s0、DcD和NaZsZ伍处理较低，分别较对照处理低44.践一“.5%、31 .7%一50.6%和34.9%一49.3%.四季葱生物量与土壤PH过低有关，以DcD处理较高，施用尿素和破酸氮按下分别比CK处理高16.2%和8.2%，而以s0和50+DCD处理最低.因此，在酸性土壤施入s0应采取措施调节土壤PH值. 5、s0的施用还可提高土壤有效硫含量，特别是在缺硫土壤，可使其达到硫丰畜状态。 综合本研究，作者认为在有效硫含量较低的跪莱地土壤上可施用s0和SO+DCD达到延缓州山气N琦化，减少NO3一淋溶报失.更多还原

【Abstract】 The leaching loss of NO3- from soils not only decrease fertilization nitrogen efficiency, but also result in pollution of surface/ground water. One incubation and two leaching experiments were conducted to investigate the effect of supplied element sulphur (S0) and DCD on leaching loss of NO3-from vegetable soil, and nitrification of soil NH4+.The results of soil incubation experiment was summarized as bellow:1. Added S0 and DCD could inhibit nitrification of soil NH4+, decrease soil NO3--N content, and maintain a high soil NH4+-N content within 72 days at NH4HCO3 treatment, and within 48days at urea treatment. During period of incubation for 72 days, treatments of DCD+S0, DCD+Na2S2O3 and DCD showed high nitrification ratio among of seven treatments, nitrification ratio followed the decrease order as bellow: DCD+S0 > DCD+Na2S2O3 >DCD.2. Average soil NH4+-N contents was 27.7 - 31.3 mg/kg at DCD treatment, which was 2.6-2.7 times and 3.1 -3.9 times of those at S0 and Na2S2O3 treatment respectively, implying DCD had the best nitrification inhibition among of three inhibitors (DCD, S掳,Na2S2O3). The nitrification inhibition was greater at treatment of DCD combined with S掳or Na2S2O3 than DCD treatment. This could be contributed to inhibition of S2O32- originated from oxidation of S0 on decomposition of DCD.The results of leaching experiment was summed up as fellow:1. Added S0 and DCD could decrease obviously leaching loss of nitrogen, increase inorganic nitrogen content in soil. Inhibition effect of S0 and DCD on leaching loss of nitrogen was in dependence on soil types, which was greater on the Fimic Anthrosols than on the Calcaric Cambisol. On the Calcaric Cambisol, The NO3--N was predominately nitrogen forms in soil and exuates. An obvious inhibition of added S0 and Na2S2O3 on leaching loss of nitrogen from soil was observed, however the effect was not found at DCD treatment. Under the condition of urea and NH4HCO3 as nitrogen source, leaching loss of NO3--N at added S0 treatment decreased by 40.4% and 10% relative to without S掳 treatment,leaching loss of NO3’-N at added NaS2O3 treatment decreased by 59% and 10.5% relative to without S treatment. On the Fimic Anthrols, the NH4+-N was predominately inorganic nitrogen forms in soil. Treatments of S+DCD and S had a lowest leaching loss of NO3’-N among seven treatments, less than 70% cumulative leaching loss of NO3~-N was found at treatments of S+DCD and S relative to CK.2. Effect of nitrification inhibitor on leaching loss of nitrogen was in dependence on soil types, inhibitor, and nitrogen sources. On the Calcaric Cambisol, Na2S2O3 showed the best inhibitor in decreasing leaching loss of nitrogen, followed by S. On the Fimic Athrosols, S was the best inhibitor in decreasing leaching loss of nitrogen, and the next Na2S2O3. Leaching loss of NO3~-N was less at treatment of DCD combined with S掳or Na2S2O3 than DCD treatment. Inhibition effect of S and Na2S2O3 on leaching loss of NO3--N was better at urea treatment than at NH4HCO3 treatment. It could be contributed to inhibition of S2O32- and S4O62- originated from oxidation of S掳 in soil on urease activity.3. Application of S and DCD could increase vegetable yield, and reduce NO3~-N content in tissues of vegetable. Under the condition of urea as nitrogen source, and biomass yield of greengrocery was 24.6% and 15.8% greater at treatments of DCD and S+DCD than CK. Under the condition of NH4HCO3 as nitrogen source, biomass yield of greengrocery was 24.5% and 14.8% greater at S+DCD and S treatment than CK. The NO3-N content in tissues of vegetable were 44.8% ~ 64.5%, 31.7% ~ 50.6% and 34.9% -49.3% lower at treatments of S, DCD and Na2S2O3 relative to CK.To integrate the present study result, we suggested that S and S+DCD could be used as nitrification inhibitor to postpone nitrification of NH4+- N, subsequently decrease leaching loss of NO3--N from vegetable soil with low soil available sulphur.更多还原