生化抑制剂组合与施肥模式对黄泥田稻季氨挥发的影响

为探讨生化抑制剂组合与施肥模式对黄泥田稻季氨挥发的影响,采用二因素随机区组设计,研究生化抑制剂组合[N-丁基硫代磷酰三胺(NBPT)、N-丙基硫代磷酰三胺(NPPT)和2-氯-6-(三氯甲基)吡啶(CP)]与施肥模式(一次性和分次施肥)互作对黄泥田稻季氨(NH3)挥发动态变化的影响。结果表明:黄泥田稻季NH3挥发损失主要集中于施肥后1周,峰值发生在第1~3 d。生化抑制剂组合与施肥模式对黄泥田稻季NH3挥发损失量的效应显著。尿素分次施用处理稻季NH3挥发净损失率较一次性施用处理显著降低24.6%。不同施肥模式下,硝化抑制剂CP处理显著提高田面水NH+4-N峰值和NH3挥发速率峰值,增加稻田NH3挥发损失量;脲酶抑制剂NBPT/NPPT或配施CP处理明显延缓尿素水解,降低NH3挥发速率峰值,减少稻田NH3挥发损失量。新型脲酶抑制剂NPPT单独施用及与CP配施的稻田NH3挥发动态变化与NBPT相似。相关性分析表明,稻田NH3挥发速率与田面水NH+4-N浓度和pH值呈显著正相关,而与气温、土温和土壤相对湿度无显著相关性。总之,生化抑制剂组合与适宜的运筹相结合更能有效减少黄泥田稻季NH3挥发损失。     

脲酶抑制剂NBPT对鸡粪好氧堆肥的保氮效果

利用堆肥反应器, 以鸡粪和蘑菇渣为原料进行好氧堆肥, 在堆肥中添加不同浓度的脲酶抑制剂NBPT, 研究其对堆肥氮素转化的影响及保氮效果。结果表明: 添加不同浓度的脲酶抑制剂NBPT对堆肥进程中温度无显著影响, 在堆肥的高温阶段可有效控制堆料pH的升高, 在堆肥高温前期的0~10 d可有效降低堆肥的脲酶活性, 在堆肥中后期10~25 d明显提高全氮含量。堆肥25 d后, 添加0.04 mL·kg^-1、0.08 mL·kg^-1、0.16 mL·kg^-1脲酶抑制剂NBPT分别比CK减少氮素损失6.61%、4.89%和13.51%。堆肥过程中, 堆料铵态氮含量呈升-降-升-降的双峰趋势, 且大部分时间CK处理的铵态氮含量高于添加脲酶抑制剂NBPT处理, 且CK处理铵态氮的两次升高速度均高于添加脲酶抑制剂NBPT处理。在堆肥的升温和高温期硝态氮含量不稳定, 但堆肥结束时, 各添加脲酶抑制剂NBPT处理的硝态氮含量显著高于CK处理。本试验结果表明, 在堆肥过程中添加脲酶抑制剂NBPT可延缓鸡粪中的尿素态氮向铵态氮的转化, 增加堆肥成品中的硝态氮含量。在畜禽粪好氧堆肥中加入脲酶抑制NBPT可起到一定的保氮作用。     

脲酶抑制剂不同用量对土壤氮素供应的影响

为研究在红壤双季稻田脲酶抑制剂适宜的添加比例,采用田间小区试验研究不同水平的脲酶抑制剂N-丁基硫代磷酰三胺(NBPT)对双季稻田土壤氮素转化的影响。本文设置NBPT的施用量为尿素的0. 5%、0. 75%、1. 0%、1. 25%、1. 5%5个水平。结果表明:与农民习惯施氮(单施尿素N 135 kg/hm~2)处理相比,NBPT与尿素的比例1. 0%时,对早、晚稻的产量与氮素回收率均无显著影响,当NBPT添加比例为1. 0%、1. 25%、1. 5%时,早、晚稻的产量以及氮素回收率均显著提高,且添加量在1. 0%与1. 5%的两个处理之间无显著差异;与单施尿素相比,添加NBPT大于1. 0%时,土壤脲酶活性和铵态氮含量在分蘖期显著降低,铵态氮含量在孕穗期显著升高,而硝酸还原酶活性、硝态氮含量及微生物量碳、氮含量始终无明显差异,孕穗期的脲酶活性也无显著差异;通过逐步回归分析发现,水稻分蘖期与孕穗期土壤中铵态氮含量对水稻产量影响显著,而且孕穗期的影响大于分蘖期,其余指标则对产量无明显影响,由此可知,添加NBPT可保持孕穗期较高的土壤铵态氮含量可能是其增产与提高氮肥利用率的主要原因,NBPT在稻田的适宜添加量为尿素用量的1. 0%以上。     

15N-Urea Efficiency in Maize as Influenced by Humic Substances and Urease Inhibitors Treatments

Urea treated with urease inhibitors (UI) in association with humic substances (HS) is expected to improve urea efficiency by reducing ammonia losses and also provide the benefits of HS such as improve nitrogen (N) recovery by plants. Ammonia volatilization (AV), ¹⁵N recovery efficiency in the soil (NRE) and ¹⁵N use efficiency (NUE) were evaluated in maize (Zea mays L.) in a greenhouse pot trial. Treatments consisted of ¹⁵N-urea treated with UI (0, 0.4% boron (B) +0.15% copper (Cu), 0.64% B, and NBPT (N-(n-butyl) thiophosphoric triamide)) and three levels of HS (0%, 0.6%, and 1.2%). A control treatment (without N) was also included. N treatments were applied at V4 (vegetative leaf stage 4) on soil surface. HS was not efficient on AV reduction, NBPT had the greatest reduction in AV, and B had higher efficiency on AV reduction than Cu. At V8 (vegetative leaf stage 8), NBPT had the greatest NUE followed by B. At VT (tassel fully emerged), NUE from urea treated with NBPT reduced when increased levels of HS, and NBPT had the greatest NRE. UI in association with HS treated-urea does not reduce AV and it does not improve NUE by maize in vegetative stages.     

Ammonia Volatilization from Soil,Dry-Matter Yield,and Nitrogen Levels of Italian Ryegrass

Nitrogen (N) loss by ammonia (NH₃) volatilization is the main factor for poor efficiency of urea fertilizer applied to the soil surface. Losses can be suppressed by addition of zeolite minerals to urea fertilizer. The objective of this study was to evaluate ammonia volatilization from soil and dry-matter yield and nitrogen levels of Italian ryegrass. A greenhouse experiment was carried out with the treatments of urea, urea incorporated into soil, urea + urease inhibitor, urea + zeolite, ammonium nitrate, and unfertilized treatment. Ammonia was captured by a foam absorber with a polytetrafluoroethylene tape. There were few differences between zeolite and urease inhibitor amendments concerning NH₃ volatilization from urea. Results indicate that zeolite minerals have the potential to improve the N-use efficiency and contributed to increasing N uptake. Zeolite and urea mixture reduced 50% the losses by volatilization observed with urea.     

Reducing NH3, N2O and {\text{NO}}_3^ - –N losses from a pasture soil with urease or nitrification inhibitors and elemental S-amended nitrogenous fertilizers

A 3-month field experiment comparing nitrogen (N) losses from and the agronomic efficiency of various N fertilizers was conducted on a sandy loam (Typic Hapludand) soil at Ruakura AgResearch farm, Hamilton, New Zealand during October to December 2003. Three replicates of seven treatments: urea, urea + the urease inhibitor N-(n-butyl) thiophosphoric triamide (trade name Agrotain), urea + Agrotain + elemental sulphur (S), urea + double inhibitor [DI; i.e., Agrotain + dicyandiamide (DCD)], diammonium phosphate (DAP), DAP + S, each applied at 150 kg N ha⁻¹, and control (no N). After fertilizer application, soil ammonium () and nitrate () concentrations (7.5-cm soil depth), ammonia (NH₃) volatilization, nitrate () leaching, nitrous oxide (N₂O) emission, pasture dry matter, and N uptake were monitored at different timings. Urea applied with Agrotain or Agrotain + S delayed urea hydrolysis and released soil at a slower rate than urea alone or urea + DI. Urea applied with DI increased NH₃ volatilization by 29% over urea alone, while urea + Agrotain and urea + Agrotain + S reduced NH₃ volatilization by 45 and 48%, respectively. Ammonia volatilization losses from DAP were lower than those from urea with or without inhibitors. Total reduction in leaching losses for urea + DI and urea + Agrotain compared to urea alone were 89% and 47%, respectively. Application of S with urea + Agrotain reduced leaching losses by an additional 6%. Nitrous oxide emissions were higher from the DAP and urea alone treatments. Urea applied with DI and urea + Agrotain reduced N₂O emissions by 37 and 5%, respectively, over urea alone. Compared to urea alone, total pasture production increased by 20, 17, and 15% for urea + Agrotain + S, urea + Agrotain, and urea + DI treatments, respectively, representing 86, 71, and 64% increases in N response efficiency. Total N uptake in urea + Agrotain, urea + Agrotain + S, and urea + DI increased by 29, 22, and 20%, respectively, compared to urea alone. These results suggest that the combination of both urease and nitrification inhibitors may have the most potential to reduce N losses and improve pasture production in intensively grazed systems.     

Urea N uptake efficiency of ryegrass (Lolium perenne L.) in the presence of urease inhibitors

Summary A greenhouse experiment was conducted to study the comparative efficiency of urea as an N fertilizer with and without the addition of different urease inhibitors. Ryegrass (Lolium perenne L.) was used as the test plant and the N balance technique with ¹⁵N was applied. Three urease inhibitors, hydroquinone, phenyl phosphorodiamidate (PPDA), and N-(n-butyl) phosphorothioic triamide (NBPT), were evaluated for their effects on urea-N uptake as well as on grass yield. The addition of urease inhibitors, except for hydroquinone in the later growth period, did not significantly influence the dry matter weight. Throughout the whole growth period, only NBPT significantly increased the total urea-N uptake. In the uninhibited system, the major fertilizer N loss occurred during the first period of grass growth, presumably via NH₃ volatilization, since the environment did not favour the other pathways of N loss. However, an appreciable amount of urea N was lost during the later growth period in all inhibited systems, especially in the hydroquinone-treated system. This indicates that the application of urease inhibitors could not eliminate the urea N loss. The greater N loss in the hydroquinone-treated soil appears to be related to the inhibition by hydroquinone of nitrification.     

NBPT/DMPP对白浆土中尿素态氮转化调控效果研究

采用室内恒温、恒湿培养方法,研究不同剂量NBPT、DMPP及其组合对尿素态氮在三江平原白浆土中的转化作用效果.研究表明,NBPT在白浆土上的作用时间不到14天.NBPT可以有效减少尿素的水解,2.5％NBPT效果好于0.5％NBPT.DMPP有效抑制白浆土中NH4+-N向NO3+-N的转化,其有效调控时间长达45天以上,1％DMPP与5％DMPP作用效果相差不大.NBPT和DMPP组合处理作用效果优于仅添加NBPT或者DMPP处理.0.5％NBPT+1％DMPP组合处理可以有效地抑制尿素水解和保持土壤中大量的氮以NH4+-N的形式存在.     

Nitrogen Fertilization of Soybean Affects Root Growth and Nodulation on Two Soil Types in Mississippi

Greenhouse studies were conducted to evaluate the influence of nitrogen (N) sources [urea + ?N-(n-butyl) thiophosphoric triamide, NBPT (urease inhibitor) and polymer-coated urea (PCU)] and rates on soybean root characteristics, nodule formation, and biomass production on two soil types (silt loam and clay) commonly cropped to soybean in Mississippi. About 15% less belowground biomass was produced in clay soil than in silt loam soil directly corresponding to all other root parameters including root length, root area, root diameter, and nodule number. Pooled across N rates, N additions resulted in 19% and 52% decrease in belowground biomass and number of nodules, respectively, across soils compared to soybean receiving no N. The N rate was the most critical factor as it influenced all root growth parameters. Number of nodules were 24% greater with PCU than urea + NBPT. Nitrogen additions and clay soil negatively impacted soybean root growth, nodulation, and belowground biomass production.

Abbreviations: Polymer-coated urea, PCU; N-(n-butyl) thiophosphoric triamide, NBPT     

土壤温度和含水量互作对抑制剂抑制氮素转化效果的影响

为比较生化抑制剂组合对土壤氮素转化的抑制效果,揭示不同土壤温度和含水量互作对尿素水解抑制效应的影响。该文采用室内模拟培养方法,研究土壤含水量(60%和80%田间最大持水量,water holding capacity,WHC)和土壤温度(15、25和35℃)互作对生化抑制组合[N-丁基硫代磷酰三胺(N-(n-butyl)thiophosphoric triamide,NBPT)、N-丙基硫代磷酰三胺(N-(n-propyl)thiophosphoric triamide,NPPT)和2-氯-6(三氯甲基)吡啶(2-chloro-6(trichloromethyl)pyridine,CP)在黄泥田土壤中抑制氮素转化效果的影响。结果表明:土壤温度和含水量对生化抑制组合在黄泥田土壤中抑制尿素水解效应显著,以土壤温度影响更大。随着土壤温度增加,尿素水解转化增强,有效作用时间降低,硝化作用增强,脲酶和硝化抑制效应减弱;随着土壤含水量降低,尿素水解转化缓慢,有效作用时间延长,硝化作用减弱,脲酶和硝化抑制效应增强。不同土壤温度和含水量条件下,NBPT/NPPT或配施CP处理有效抑制黄泥田土壤脲酶活性,延缓尿素水解;CP或配施NBPT/NPPT处理有效抑制NH4+-N向NO_3~--N转化,保持土壤中较高NH_4~+-N含量长时间存在。新型脲酶抑制剂NPPT单独施用及与CP配施的土壤尿素水解抑制效果与NBPT相似。黄泥田土壤中生化抑制组合应用最佳的土壤温度和含水量分别为25℃和60%WHC。总之,针对不同土壤温度和含水量条件,在黄泥田土壤中应采用脲酶抑制剂与硝化抑制剂相结合的施肥方式。