3,4二甲基吡唑磷酸盐和双氰胺在黑钙土中对尿素氮转化的作用效果

采用室内培养试验,以普通尿素为对照,研究双氰胺(DCD)、3,4-二甲基吡唑磷酸盐(DMPP)和缓释尿素在东北黑钙土中对尿素氮转化的作用效果。结果表明,缓释尿素对尿素水解有一定的限制作用。0.5%DMPP对抑制氨氧化作用效果最好,保持低表观硝化率时间最长,硝化抑制率最高,有效作用时间最长,最佳有效抑制时间为42 d,有效作用时间可达63 d,显著好于2%DCD;2%DCD也有显著的抑制效果,保持低表观硝化率时间较长,硝化抑制率较高,最佳抑制时间为35 d,有效作用时间超过56 d,缓释尿素最佳作用时间为7 d,有效作用时间可达35 d。作用效果为添加0.5%DMPP+尿素添加2%DCD+尿素缓释尿素普通尿素。     

氮肥增效剂对海南砖红壤土壤氮转化影响的研究

抑制剂施用能显著降低尿素及含脲肥料施用带来的环境问题。通过室内培养试验,对硝化抑制剂双氰胺(DCD)和氯唑灵(Dwell)以及长效复混肥添加剂(NAM)对海南花岗岩母质土壤尿素氮转化的影响进行研究。结果表明,NAM和DCD可提高土壤NH4+-N含量,抑制硝化作用,可应用到海南地区以尿素作为氮源的肥料中,其推荐用量分别为施入纯氮量的0.8%和3.5%。但由于NAM和DCD能在较长一段时间内显著提高土壤酸碱度,有导致土壤氨挥发加大及NO2-积累的风险,建议在施肥时不要集中大量施用。     

长期施肥配施DCD处理对菜地土壤N2O短期排放影响的模拟研究

为研究长期不同肥源配施双氰胺（Dicyandiamide,DCD）对菜地土壤氧化亚氮（N₂O）等温室气体短期排放规律的影响,本研究以长期不同肥源配施 DCD 的定位试验土壤为研究对象,通过短期室内模拟培养试验,研究牛粪（OM）、化肥（F）、牛粪+DCD（OMD）、化肥+DCD（FD）和 1/2化肥+1/2牛粪（FOM）5个处理在不同温度下 15 d内的 CO₂、N₂O、CH₄动态变化特征和累积排放量。结果表明：15 ℃和25 ℃条件下各施肥处理CO₂累积排放量分别为25.39~52.01 mg·k^-1和62.35~122.80 mg·k^-1,N₂O累积排放量分别为6.02~16.60 μg·k^-1和14.45~117.78 μg·k^-1,CH₄累积排放量分别为-3.17~14.87 μg·k^-1和4.09~23.56 μg·k^-1。与15 ℃相比,25 ℃条件下除FOM处理外,其他处理N₂O与CO₂累积排放量均显著增加（P<0.05）。相比于OM和OMD处理,F、FD、FOM处理在两种温度条件下 CO₂排放都显著降低;在 25 ℃下,OMD、FD、FOM 处理 N₂O 排放峰值和累积排放量较 OM 和 F 处理显著降低（P<0.05）,在15 ℃下,所有处理N₂O累积排放量差异均不明显。短期排放模拟研究显示,CO₂排放量与土壤pH、总氮（TN）含量呈极显著正相关,与速效磷（Olsen-P）含量呈极显著负相关,15 ℃条件下CH₄累积排放量与土壤有机质（SOM）呈极显著正相关（P<0.01）。研究表明,较高温度条件下,与有机肥或化肥单施相比,长期配施DCD或有机无机配施能显著减少菜地土壤N₂O排放。研究结果可为长期施用DCD的菜地土壤温室气体排放提供参考。     

化学抑制型氮素释放延缓剂对玉米产量和品质的影响

以大、中、小3种穗型玉米品种为试材,研究脲酶抑制剂(NBPT)以及脲酶抑制剂与硝化抑制剂(DCD)组合(NBPT DCD)对玉米单株产量和子粒营养品质的影响。结果表明,化学抑制型氮素释放延缓剂可增加玉米的成粒数,有效提高玉米子粒的蛋白质含量和淀粉含量。不同类型抑制剂对不同穗型玉米品种的影响不同。大穗型品种丹玉39的蛋白质含量对NBPT DCD的反应敏感;中穗型品种郑单958的成粒数对两种抑制剂组合的反应敏感;而小穗型品种四单19对抑制剂的反应不敏感。因此,生产中应根据玉米品种不同选用适合的氮素释放延缓剂。     

双氰胺单次配施和连续配施的土壤氮素形态和蔬菜硝酸盐累积变化

采用田间试验研究了双氰胺(dicyandiamide,缩写DCD)单次配施和连续配施的土壤氮素形态和蔬菜硝酸盐累积变化。结果表明,与单施化肥相比,DCD单次配施的长期叶菜甘蓝生长过程中土壤铵态氮含量增幅为21.3%-339.4%,土壤硝态氮和菜体硝酸盐含量降幅分别为5.4%-80.2%和4.4%-58.3%;短期叶菜空心菜收获时土壤铵态氮含量增加了299.4%,土壤硝态氮和菜体硝酸盐含量分别降低了26.2%和31.7%。DCD连续配施的\"甘蓝-菠菜-空心菜-萝卜-大白菜\"种植体系中,土壤铵态氮、硝态氮和菜体硝酸盐含量均呈累积的趋势,配施DCD的土壤铵态氮含量从略高于化肥处理(44.0%)发展到极显著高于化肥处理(392.5%,P<0.01),土壤硝态氮含量从极显著低于化肥处理(-68.2%,P<0.01)发展到显著高于化肥处理(146.6%,P<0.05),菜体硝酸盐含量从显著低于化肥处理(-30.2%,P<0.05)发展到极显著高于化肥处理(40.4%,P<0.01)。由此可见,DCD单次配施可显著降低菜体硝酸盐含量,而连续配施DCD的土壤能维持一定量的铵态氮水平,这些盈余的铵态氮会进一步转化为硝态氮残留在土壤中,并可能产生蔬菜硝酸盐累积的风险。     

Effects of Conventional and Stabilized Urea Fertilizers on Soil Biological Status

Effects of stabilized urea fertilizers [Alzon 46 (A) and UREAstabil (US)] on soil microbiological and chemical parameters and also on grain yield, 1000-grain weight, and oil content were tested in a precise field study on Luvisol in 2010–2012. Winter rapeseed (Brassica napus L. cv. Californium) was fertilized both in autumn [45 kg nitrogen (N) ha^?1] and in spring (155 kg N ha^?1) with A [urea with DCD (dicyandiamide) plus pyrrodiazole (1,2,4-1H-triazole)], US {urea with NBPT [N-(n-butyl)-thiophosphoric acid triamide]}, and conventional N fertilizers (pure urea, calcium ammonium nitrate). Eleven parameters were used to evaluate the soil status: microbial biomass carbon (C; microwave method [MW]), dehydrogenase activity, arylsulfatase activity, available organic carbon, electroconductivity, C_org (MW method), and pH (in water, H₂O). None of the 11 parameters demonstrated significant difference between control, conventional N fertilizers, and stabilized urea fertilizers. The greatest yield significantly different from the control (zero kg N ha^?1; 2598 ± 881 kg ha^?1) was found for both stabilized urea fertilizers: A (200 kg N ha^?1; 3772 ± 759 kg ha^?1) and US (200 kg N ha^?1; 3764 ± 625 kg ha^?1). The control achieved the greatest oil content (46.0 ± 1.2%), which was significantly different from all N-fertilized variants, and also the greatest 1000-grain weight (5.62 ± 0.62 g).     

双氰胺对氮肥增产效益的影响

分析了水田和旱田应用双氰胺(不同用量+氮素)的增产效益。结果表明:双氰胺在水田条件下(施用量8～32kg/hm2),增产幅度为12.2%～14.3%,最高产量施用量为21.4kg/hm2,最佳经济产量施用量为20.97kg/hm2,施用比例为1∶0.11～0.15。在旱田条件下(施用16.5～49.5kg/hm2),增产3.4%～6.6%,最高产量施用量为38.6kg/hm2,最佳经济产量施用量为33.9kg/hm2,其比例为1∶0.15～0.18,可作为玉米的安全生长用量。     

Correlation Studies on Ammonium/Nitrate Concentrations in Soil and Growth and Yield of Wheat

A field experiment was conducted at the Indian Agricultural Research Institute, New Delhi to study the growth and yield of wheat as influenced by the concentrations of ammonium-N and nitrate-N in soil. A series of ammonium and nitrate nitrogen concentrations in soil on a time frame was developed by treating prilled urea with nitrification inhibitors DCD or neem cake as well as by changing the dose and time of N application. The study revealed that number of tillers m^-1 as well as ears m^-1 row length were significantly positively correlated with ammonium-N concentration at 15 and 30 DAS and nitrate-N concentration at 30 and 45 DAS. Number of grains ear^-1 was significantly positively correlated with ammonium-N at 30, 45 and 60 DAS and nitrate-N at 45 and 60 DAS. Ultimately grain yield in wheat was significantly positively correlated with ammonium-N concentration at 15 and 30 DAS and nitrate-N concentration at 30, 45 and 60 DAS. The response between grain yield and concentrations of both ammonium and nitrate forms of N was quadratic. The optimum concentration of ammonium-N in soil for maximum grain yield gradually decreased with the age of the crop from 54.6 to 63.6 μg g^-1 at 15 DAS to 22.7 to 26 μg g^-1 at 30 DAS. In the case of nitrate-N its optimum concentration for maximum grain yield increased with age of the crop from 25.1 to 30 μg g^-1 at 15 DAS to 31.6 to 34 at 45 DAS and it decreased thereafter.     

1-羟甲基-3,5-二甲基吡唑(DMHMP)的硝化抑制效应初探

采用室内好气培养方法,以DCD为参比对象研究了新型硝化抑制剂1-羟甲基-3,5-二甲基吡唑(DMHMP)对土壤硝化作用的影响。研究结果表明,DMHMP同DCD一样对土壤硝化作用有明显的抑制效应,主要表现在三个方面:(1)可使土壤NH4+-N含量在整个培养期内显著高于不添加抑制剂的对照处理(P<0.01);(2)使土壤NO3--N含量显著低于对照处理(P<0.01);(3)添加硝化抑制剂处理土壤的pH下降幅度和速度均较对照处理有所降低.当添加DMHMP的量与DCD相等时,其硝化抑制作用不如DCD,而当其添加量为DCD的2倍时,其硝化抑制效果明显优于DCD.在培养的第7天至第21天之间,DMHMP具有最优的硝化抑制效应。     

双氰胺在玉米苗期的使用研究

实验研究了双氰胺在玉米苗期对土壤微生物细菌、霉菌和放线菌的影响,及对土壤中铵态氮和硝态氮贮量变化的影响。结果表明:双氰胺对土壤中的细菌、放线菌生长具有促进作用,对土壤中的霉菌生长具有抑制作用。并且双氰胺通过其硝化抑制作用可以延缓铵态氮的硝化速率,使施入的碳铵能较长时间的以铵态氮的形态存在。