尿素施肥方式对水稻增产增效和土壤氮素损失的影响

【目的】探讨尿素施用量、基施比例和方法对水稻产量、吸氮量和氮肥利用率的影响,以及肥料氮的去向,为制定科学合理的施氮措施提供理论依据。【方法】水稻季田间试验于2019年和2020年在江苏太湖地区开展。供试脲酶抑制剂为N-丁基硫代磷酰三胺(NBPT),硝化抑制剂为对羟基苯丙酸甲酯(MHPP),二者用量均为施氮量的1%。试验共设6个处理：1)不施氮肥对照(CK);2)表施尿素N 300 kg/hm² (当地常规施肥,CN);3)表施尿素N 225 kg/hm² (RNB);4)尿素N 225 kg/hm²,50%表施,50%深施(RND);5)表施尿素N 225 kg/hm²+NBPT+MHPP (RNB+DI);6)尿素N 225 kg/hm²+NBPT+MHPP,50%表施,50%深施(RND+DI)。表施氮肥处理基肥∶分蘖肥∶孕穗肥为4∶3∶3;深施氮肥处理基肥∶孕穗肥为7∶3。2020年在处理小区内设置了¹⁵N示踪微区试验。调查了水稻产量、吸氮量、氮肥利...     

双季稻田添加脲酶抑制剂NBPT氮肥的最高减量潜力研究

【目的】添加脲酶抑制剂（Urease inhibitor, UI）是提高肥料利用率的有效途径,在尿素（Urea,U）中添加1%的脲酶抑制剂NBPT（N-丁基硫代磷酰三胺）是目前研究使用证明效果最可靠的添加比例。针对当前稻田氮肥施用水平过高的问题,本文采用田间小区试验研究了目前脲酶抑制剂添加比例下稻田氮肥的减施潜力以及脲酶抑制剂的节肥增效机理。【方法】本试验在我国长江中下游的双季稻田进行,脲酶抑制剂用量NBPT为尿素用量的1%。尿素用量设五个水平为N 90、 112.5、 135、 157.5 和180 kg/hm2,分别依次记为U1、 U2、 U3、 U4和U5, 7个处理为CK（不施氮肥）、 U1+UI、 U2+UI、 U3+UI、 U4+UI、 U5+UI、 U5（U5为传统施氮量, N 180 kg/hm2为农民习惯施氮量）,三次重复。U1~U5处理施氮量分别是在农民习惯施氮量的基础上降低50%、 37.5%、 25%、 12.5%、 0%。通过取样分析水稻分蘖期和孕穗期各处理对土壤脲酶活性、 硝酸还原酶活性、 土壤铵态氮含量、 硝态氮含量以及微生物量碳、 氮的含量,研究NBPT对水稻两个主要生育期土壤氮素供应的影响,比较各处理的产量以及氮肥利用率来得出氮肥的减施潜力,在此基础上通过逐步回归分析研究以上各指标对产量的影响,探明脲酶抑制剂（NBPT）在双季稻田的增效机理。【结果】 1) 在双季稻田,添加NBPT后,施氮量为N 135 kg/hm2的籽粒产量达到最高。与传统施氮（单施尿素N 180 kg/hm2）处理相比,早、 晚稻可分别增产8.54%和12.87%,氮肥当季利用率分别提高6.78%和9.46%,可节约氮肥25%; 2)与传统施氮相比,添加NBPT显著降低了水稻分蘖期的土壤脲酶活性和铵态氮含量,显著提高了孕穗期的铵态氮含量,而对此时期的脲酶活性无显著影响,NBPT对两个时期的硝酸还原酶活性、 硝态氮含量及微生物量碳、 氮含量均无明显影响,可见基施的NBPT主要是降低尿素水解速率方面效果显著,并且NBPT具有时效性,其主要是在水稻孕穗期之前起作用,在生态上较为安全; 3) 从各项土壤指标与水稻产量相关性的逐步回归分析结果来看,水稻分蘖期与孕穗期稻田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。【结论】由于脲酶抑制剂NBPT减缓了分蘖期尿素的水解作用,提高了孕穗期土壤中的铵态氮含量,为水稻后期生长提供充足的氮肥,在双季稻减肥方面具有显著的效果。在本试验土壤条件下,尿素中添加1% 的NBPT,可在提高产量的同时,将传统施氮肥量减少25%,是适于稻田应用的脲酶抑制剂。     

Alternatives to regular urea for abating N losses in lettuce production under sub-tropical climate

Alternative fertilization practices are needed for reducing gaseous and leaching N losses at high urea application rates. The objective of this study was to compare gaseous N emissions (N₂O and NH₃) and NO₃ ^? concentrations in the soil solution during two successive lettuce cropping seasons under contrasting fertilization practices. Treatments were fertilization with regular urea (U), urea treated with urease [N-(n-butyl) thiophosphoric triamide (NBPT)] and nitrification [dicyandiamide (DCD)] inhibitors (UIs), non-acidified pig slurry compost (PSC), acidified pig slurry compost (APSC), and an unfertilized control (C). Acidification of pig slurry during composting had no impact on soil cumulative N₂O emissions during the cropping seasons. The use of composts resulted in emission factors (EFs) (PSC, 0.09% of applied N; APSC, 0.16%) an order of magnitude smaller than with regular urea (1.63%). Similarly, adding NBPT and DCD to urea reduced the N₂O EF from 1.63 to 0.37% of applied N and fertilizer-induced NH₃ emissions from 30.2 to 3.4% of applied N. Composts and UI resulted in yield-scaled N₂O emissions that were 33 to 49% lower than the unfertilized control and 64 to 73% lower than the regular urea estimates, indicating a greater efficiency of supplied N with composts and UI. Nitrate concentration of the soil solution (at 0.1 and 0.3 m) in PSC, APSC, and UI plots was similar to the control and up to 17 times lower than with regular urea, indicating reduced risks for leaching losses. We conclude that, as compared to regular urea, the use of composted pig slurry, with and without acidification, and the addition of NBPT and DCD inhibitors to urea are good practices to reduce environmental N losses from lettuce production under sub-tropical climate.     

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。     

硝化和脲酶抑制剂对华北冬小麦-夏玉米轮作固碳减排效果评价

全面、准确分析重要农业管理措施对于农业固碳减排的影响特征,对于中国农业可持续发展具有重要意义。该文以华北平原冬小麦-夏玉米生产为对象,研究硝化/脲酶抑制剂对土壤温室气体(CO_2、N_2O和CH4)排放、土壤有机碳和作物产量的影响;在此基础上利用土壤碳库排放法(soil based approach,SBA)、生物量排放法(crop based approach,CBA)和土壤生物量排放法(soilcrop based approach,SCBA)3种方法对农田净温室气体效应(net greenhouse gas warming potential,NGWP)进行评价。研究发现,相比只施尿素(U)处理,尿素+硝化抑制剂(NI)、尿素+脲酶抑制剂(UI)和尿素+硝化抑制剂+脲酶抑制剂(NIUI)均能增加粮食产量和降低净温室气体排放。用SCBA方法计算得到的农田温室气体净排放的潜力最大(15 704~17 860 kg/hm~2),CBA法次之(4 195~7 107 kg/hm~2),SBA法最低(-7 304~-6 599 kg/hm2)。由于3种方法的固碳单元不一样,评估结果差异较大、一致性差。SCBA方法更适于评价强调粮食生产条件下的农田净温室气体效应。增加作物籽粒和秸秆产量,降低化肥使用和减少灌溉量是提高当前华北平原农田温室气体系统净排放潜力的主要措施。     

脲酶/硝化抑制剂对沿淮平原水稻产量、氮肥利用率及稻田氮素的影响

添加氮素抑制剂是提高水稻氮肥利用率的有效途径之一。采用大田试验,探讨了氮素抑制剂(脲酶抑制剂N-丁基硫代磷酰三胺(NBPT)、硝化抑制剂3,4-二甲基吡唑磷酸盐(DMPP)及其组合)对沿淮平原水稻产量、氮肥利用率及稻田氮素的影响,旨在为优化沿淮稻田生态系统氮素养分管理,减少氮素损失提供科学依据。以"常糯1号"为供试材料,于2018年6—10月在安徽省怀远县(沿淮平原典型水稻种植区)进行试验。试验设5个处理:不施氮肥(CK);尿素(U);尿素+硝化抑制剂(U+DMPP);尿素+脲酶抑制剂(U+NBPT);尿素+硝化抑制剂+脲酶抑制剂(U+NBPT+DMPP)。结果表明:尿素配施NBPT或者DMPP均有利于提高水稻产量、植株吸氮量和氮素利用效率,NBPT效果优于DMPP,NBPT和DMPP联合施用表现出协同增效作用。尿素配施抑制剂的3个处理U+NBPT、U+DMPP和U+NBPT+DMPP较单独施用尿素U处理的产量分别增加6.8%,4.3%,8.6%,植物吸氮量分别增加9.6%,6.5%,12.2%,与U处理之间差异达显著水平(P0.05)。尿素单独配施NBPT或者NBPT+DMPP组合均显著提高了氮肥吸收利用率(NRE)、氮肥农学利用率(NAE)、氮素吸收效率(NUP)和氮肥偏生产力(NPFP)(P0.05),而尿素单独配施DMPP也有不同程度的提高,但差异未达到显著水平(P0.05)。另外,尿素单独配施DMPP或者DMPP+NBPT组合均显著提高了水稻成熟期土壤铵态氮(NH_4~+-N)和微生物量氮(SMBN)的含量,降低了硝态氮(NO_3~--N)的含量,提高了土壤中铵/硝比,而尿素单独配施NBPT对水稻成熟期土壤NH_4~+-N、NO_3~--N和SMBN无显著影响。总体认为,在沿淮平原稻作种植体系中,尿素配施NBPT或者DMPP可以有效地增加水稻产量,促进水稻对氮素的吸收利用,提高氮素利用效率,NBPT和DMPP联合施用效果最理想。     

Early nitrogen deficiency favors high nitrogen recovery efficiency by improving deeper soil root growth and reducing nitrogen loss in wheat

ABSTRACT

A two-year field and micro-plot ¹⁵N-labelled experiment was conducted under two levels of N application rate (240 and 180 kg N ha^–1) with three basal N application stages [seeding (L0), four-leaf stage (L4), and six-leaf stage (L6)] to investigate the effects of reducing basal N application amount and postponing basal N fertilization period on wheat growth and N use efficiency (NUE). No significant differences were observed in grain yield, root growth and root morphology between the N180L4 and N240L0 treatments, while the root-shoot ratio of N180L4 was significantly improved. Postponing basal N application period increased the residual basal ¹⁵N in soil and reduced basal ¹⁵N loss, and N180L4 treatment favored the highest ¹⁵N recovery efficiency (NRE), mainly due to reduced ¹⁵N loss. Grain yield and basal NRE were significantly positively correlated with root dry weight in deeper soil layers (40–60 cm), and the contribution of root growth to improved grain yield and NRE increased with the downward distribution of the roots. Therefore, postponing the basal N fertilization period under N deficiency promotes deeper root growth during the post-jointing period and increases basal N uptake, as well as reducing basal N loss and increasing grain yield and NUE.     

Impact of urease and nitrification inhibitors on nitrous oxide emissions from fluvo-aquic soil in the North China Plain

Little information is available on the effects of urease inhibitor, N-(n-butyl)thiophosphoric triamide (NBPT), and nitrification inhibitor, dicyandiamide (DCD), on nitrous oxide (N₂O) emissions from fluvo-aquic soil in the North China Plain. A field experiment was conducted at the Fengqiu State Key Agro-Ecological Experimental Station, Henan Province, China, to study the influence of urea added with NBPT, DCD, and combination of both NBPT and DCD on N₂O emissions during the maize growing season in 2009. Two peaks of N₂O fluxes occurred during the maize growing season: the small one following irrigation and the big one after nitrogen (N) fertilizer application. There was a significant positive relationship between ln [N₂O flux] and soil moisture during the maize growing season excluding the 11-day datasets after N fertilizer application, indicating that N₂O flux was affected by soil moisture. Mean N₂O flux was the highest in the control with urea alone, while the application of urea together with NBPT, DCD, and NBPT + DCD significantly lowered the mean N₂O flux. Total N₂O emission in the NBPT + DCD, DCD, NBPT, and urea alone treatments during the experimental period was 0.41, 0.47, 0.48, and 0.77 kg N₂O–N ha⁻¹, respectively. Application of urea with NBPT, DCD, and NBPT + DCD reduced N₂O emission by 37.7%, 39.0%, and 46.8%, respectively, over urea alone. Based on our findings, the combination of DCD and NBPT together with urea may reduce N₂O emission and improve the maize yield from fluvo-aquic soil in the North China Plain.     

Effects of phosphoroamides on ammonia volatilization and nitrite accumulation in soils treated with urea

Summary We compared the effects of N-(n-butyl) thiophosphoric triamide (NBPT), N-(diaminophosphinyl)-cyclohexylamine (DPCA), phenylphosphorodiamidate (PPD), and hydroquinone on transformations of urea N in soils. The ability of these urease inhibitors to retard urea hydrolysis, ammonia volatilization, and nitrite accumulation in soils treated with urea-decreased in the order NBPT > DPCA PPD > HQ. When five soils were incubated at 30°C for 14 days after treatment with urea (1 mg urea N g^–1 soil), on average, the gaseous loss of urea N as ammonia and the accumulation of urea N as nitrite were decreased from 52 to 5 % and from 11 to 1%, respectively, by addition of NBPT at the rate of 10 g g^–1 soil (0.47 parts of NBPT per 100 parts of urea). The data obtained support previous evidence that NBPT is more effective than PPD for reduction of the problems encountered in using urea as a fertilizer and deserves consideration as a fertilizer amendment for retarding hydrolysis of urea fertilizer in soil.     

Effects of the urease inhibitor N-(n-butyl)phosphorothioic triamide in low concentrations on ammonia volatilization and evolution of mineral nitrogen

Laboratory incubation experiments were conducted to study the influence of increasing concentrations of N-(n-butyl)phosphorothioic triamide (NBPT) on NH₃ volatilization and rate of urea hydrolysis and evolution of mineral N in Ozzano, Rimini and Carpi soils with different physicochemical characteristics. Low concentrations of NBPT reduced NH₃ losses due to volatilization after urea fertilization and the effectiveness of the inhibitor was related to the soil characteristics (e.g. high concentrations of organic C and sand). After 15 days of incubation, no significant reductions of losses were found for any of the NBPT concentrations employed in Rimini soil. The application of NBPT led to a considerable reduction of the formation of nitrite. This process was completely annulled with the highest dose of NBPT (0.5% w/w_urea) in the Carpi soil after 15 days. In Rimini soil, however, the use of NBPT was less effective in influencing nitrite formation. The use of NBPT favoured accumulation of nitrate proportional to the NBPT concentration employed while it had no influence on the NH _inf4 ^sup+ fixation by 2:1 layer silicates. The data obtained support previous evidence that NBPT is effective in reducing the problems encountered in using urea as fertilizer. However, environmental conditions and soil physicochemical characteristics may have an important influence on the effectiveness of NBPT.     

生化抑制剂和腐植酸联合添加对尿素在黑土水稻种植中氮素供应稳定性的影响

  目的  研究同时添加不同种生化抑制剂和腐植酸后尿素在黑土区水田的施用效果,为黑土区稻田新一代高效稳定性尿素肥料的研制提供理论依据。  方法  采用盆栽方法,以不施氮肥（CK）及施用尿素（N）为对照,通过测定水稻土中的氮素转化特征及水稻生理指标、产量及氮肥利用效率等的影响,探究添加腐植酸（HA）、N-丁基硫代磷酰三胺（NBPT）、3,4-二甲基吡唑磷酸盐（DMPP）和2-氯-6-三甲基吡啶（CP）及腐植酸分别与三种生化抑制剂组合制成的7种稳定性尿素肥料改善氮素供应稳定性的差异。  结果  ①相比单施普通尿素,添加腐植酸及NBPT、DMPP、CP均能提高水稻产量、吸氮量及尿素氮肥利用效率。② 相比单独施用NBPT,尿素联合添加NBPT和腐植酸后能有效抑制土壤硝化作用,分别提高水稻株高、分蘖数和叶绿素含量1.84%、13.38%和2.80%,但会降低水稻产量、叶面积指数、水稻吸氮量、氮肥利用率及偏生产力。③ 相比单独施用DMPP,尿素联合添加腐植酸、DMPP能分别提高水稻株高、分蘖数和叶绿素含量3.04%、5.20%和3.71%,显著降低土壤硝化抑制率、水稻产量、水稻吸氮量、氮肥利用率及偏生产力（P < 0.05）。④ 相比单独施用CP,尿素联合添加腐植酸、CP提高了土壤速效氮含量、水稻株高、分蘖数、叶绿素含量、生物产量,显著提高水稻籽粒产量、水稻吸氮量、氮肥利用率及偏生产力（P < 0.05）。  结论  腐植酸与CP联合添加制成新型稳定尿素肥料用于在东北黑土区水稻栽培,有利于作物增产及氮肥利用率的提高。     

Nitrogen use efficiency and nutrient partitioning in maize as affected by blends of controlled-release and conventional urea

ABSTRACT

Blends of controlled-release urea (CRU) and conventional urea can be an alternative to conventional fertilization to improve nitrogen use efficiency (NUE) and reduce costs when applied as a single application to agricultural crops. Different indexes of NUE, grain yield, nutrient uptake and partitioning in maize (Zea mays L.) were investigated in field experiments. The treatments consisted of a single rate of 180 kg N ha^?1 with different proportions of polymer-sulfur coated urea (PSCU) and conventional urea (U) applied incorporated at sowing (0.05 m below and 0.1 m to the side of the seed row) at two tropical sites (Site 1, Typic Haplustox; Site 2, Rhodic Haplustox) in Brazil. A control treatment (without urea-N) and a treatment with conventional urea management (UCM: 20% of urea-N applied as basal fertilizer and 80% of N applied as top dressing) were also included. This study demonstrates that blends of PSCU and U are efficient in supplying N throughout the maize cycle at a Typic Haplustox site when applied in a single application incorporated at sowing, resulting in high yields and adequate macronutrient uptake. PSCU improved NUE index compared to U and UCM. There was not response for N fertilization in the Rhodic Haplustox site.     

Effect of soil acidification on the growth and nitrogen use efficiency of maize in Ultisols

Purpose

To examine the effect of soil acidification on growth and nitrogen (N) uptake by maize in Ultisols.

Materials and methods

A clay Ultisol derived from Quaternary red earth and a sandy Ultisol derived from tertiary red sandstone were used in this study. A pot experiment was conducted with maize growing in the two Ultisols acidified to different pH values. Urea with ¹⁵N abundance of 10.11% was used to investigate the distribution of N fertilizer between soil and plant. Total N content and ¹⁵N abundance in plant and soil samples were determined by elemental analysis-isotope mass spectrometry.

Results and discussion

Critical soil pHs of 4.8 and 5.0 were observed for maize growing in the clay and sandy Ultisols, respectively. Below the critical soil pH, increasing soil pH significantly increased maize height and the yield of maize shoots and roots (both P < 0.05), but changes in soil pH showed no significant effect on maize growth above the critical soil pH in both Ultisols. Maize growing in the sandy Ultisol was more sensitive to changes in soil pH than in the clay Ultisol. Increase in the pH in both Ultisols also increased N accumulation in maize, the N derived from fertilizer in maize, physiological N use efficiency, and N use efficiency (NUE) by maize. Changes in soil pH had a greater effect on these parameters below the critical soil pH, compared to above. The change in soil pH had a greater effect on N accumulation in maize, the N derived from fertilizer in maize, and NUE in the sandy Ultisol than in the clay Ultisol. The NUE increased by 24.4% at pH 6.0, compared with pH 4.0 in the clay Ultisol, while the NUE at pH 5.0 was 4.8 times that at pH 4.0 in the sandy Ultisol. The increase in soil pH increased the ratio of N accumulation in maize/soil residue N and decreased the potential loss of fertilizer N from both Ultisols.

Conclusions

Soil acidification inhibited maize growth, reduced N uptake by maize, and thus, decreased NUE. To maintain soil pH of acidic soils above the critical values for crops is of practical importance for sustainable food production in acidic soils.

     

Stability of stored N-(n-butyl) thiophosphoric triamide (NBPT) treated urea-based fertilizers

ABSTRACT

The effectiveness of N-(n-butyl) thiophosphoric triamide (NBPT) in reducing ammonia volatilization from urea-based fertilizers has been thoroughly investigated. However, the stability of this inhibitor during storage of NBPT treated urea and urea ammonium nitrate (UAN) needs further investigation. We compared ammonia volatilization from NBPT treated urea (360 mg NBPT kg^?1 urea) and UAN (180 mg NBPT L^?1 UAN) that were stored at room temperature for 6, 3 and 0 months. We measured ammonia volatilization with cylindrical chambers fitted with acid-charged discs at five times for 21 d. Total ammonia volatilization (measured as a % of applied nitrogen) was significantly greater in untreated urea and UAN (32% to 33%) than those in NBPT treated urea and UAN (6% to 12%). Reduction of ammonia volatilization was not significantly different among NBPT treated urea (73% to 81%) and UAN (63% to 73%) irrespective of storage time. This implies that farmers can mix their urea-based fertilizers with NBPT formulation 6 months prior to fertilization without compromising the ammonia volatilization reducing property of the NBPT.     

氮肥配施增效剂实现寒地水稻增产、提质与增效

研究氮肥增效剂对寒地水稻产量、品质及氮素利用的影响,旨在为制定合理的稻田氮素管理措施及增产、提质和增效策略提供科学依据。2017年和2018年在黑龙江省方正县设置田间试验,研究氮肥配施硝化抑制剂和脲酶抑制剂对水稻产量、品质、氮素利用和转化及经济收益的影响。结果表明:尿素配施硝化抑制剂CP和脲酶抑制剂NBPT(N+NI+UI)显著提高水稻产量,2017年较氮肥处理(N)水稻籽粒、秸秆和总生物量分别增产6.4%,4.9%和5.8%,2018年分别增产8.8%,7.2%和8.2%。施用氮肥增效剂可以提高寒地水稻碾磨品质、外观品质和营养品质,并促进水稻氮素吸收,提高氮肥利用效率。与N处理相比,N+NI+UI处理水稻氮肥表观利用率、氮肥农学效率和氮肥偏生产力分别提高15.6%,19.1%和7.6%。CP和NBPT配施对氮素转化表现出明显的协同抑制效果,延迟和降低土壤NH4^+—N含量峰值,保持水稻生育期较高的NH4^+—N含量,延长了氮素供应时间。施用氮肥增效剂可使寒地水稻增收2499.08元/hm^2。可见,寒地水稻氮肥配施硝化抑制剂CP与脲酶抑制剂NBPT能够延长氮素释放周期,促进水稻氮素吸收,增加水稻产量,改善水稻品质,提高氮肥利用效率,增加经济效益。     

INFLUENCE OF HIGH TEMPERATURE AND UREA FERTILIZATION WITH N-(N-BUTYL) THIOPHOSPHORIC TRIAMIDE AND DICYANDIAMINDE ON COTTON GROWTH AND PHYSIOLOGY

The objective of this growth chamber study was to evaluate the effect of adding N-(n-butyl) thiophosphoric triamide (NBPT) and dicyandiaminde (DCD) to urea fertilizer, on the physiology and growth of cotton (Gossypiumhirsutum L.) under normal and high temperatures. Treatments consisted of two day temperature regimes, 30°C and 38°C, and five nitrogen fertilization applications: unfertilized control, 125 kg ha^?1 of urea, 93 kg ha^?1 of urea, 93 kg ha^?1 urea + NBPT, and 93 kg ha^?1 urea + NBPT + DCD. The addition of NBPT to urea fertilizer had positive effects on leaf chlorophyll, leaf area, dry matter, nitrogen (N) uptake, and N use efficiency. The absence of a significant interaction effect indicated that N fertilization was not influenced by temperature. Deficiency of N significantly decreased leaf chlorophyll, increased glutathione reductase, decreased protein and increased leaf nitrate reductase. Physiological changes under high temperature included increased plant N uptake, glutamine synthetase, leaf chlorophyll, protein content, plant height and leaf area were due to high N uptake and utilization.     

脲酶抑制剂与硝化抑制剂对稻田氨挥发的影响

采用密闭室间歇通气法和15N标记技术研究了尿素施入稻田后氨挥发损失特征以及脲酶抑制剂(N-丁基硫代磷酰三胺,NBPT)和硝化抑制剂(3, 4-二甲基吡唑磷酸盐,DMPP)对稻田氨挥发损失的影响。结果表明,稻田施用尿素后第4天氨挥发速率达到峰值,氨挥发损失主要发生在施肥后21天内。与单施尿素处理相比,添加NBPT处理的氨挥发速率峰值降低27.04%,累积氨挥发损失量降低21.65%;NBPT与DMPP配施时,氨挥发速率峰值降低12.95%,累积氨挥发损失量降低13.58%;而添加DMPP时,氨挥发速率峰值增加23.61%,累积氨挥发损失量与单施尿素的差异不显著。相关性分析表明,地表水中铵态氮浓度和pH值与氨挥发速率均达极显著正相关,说明二者是影响氨挥发速率的主要因素,而气温、 地温和水温与氨挥发速率的相关性不显著。与单施尿素相比,添加脲酶抑制剂可显著增加稻谷产量。脲酶抑制剂与硝化抑制剂配合施用可更有效地提高氮肥的回收率。综合降低氨挥发、 提高水稻产量及地上部氮肥回收率的效果,添加脲酶抑制剂以及脲酶抑制剂与硝化抑制剂配施的两个处理效果较为理想,硝化抑制剂不宜单独添加。     

Can the agronomic performance of urea equal calcium ammonium nitrate across nitrogen rates in temperate grassland?

In temperate grassland, urea has been shown to have lower nitrous oxide emissions compared to ammonium nitrate‐based fertilizer and is less expensive. However, nitrogen (N) loss via ammonia volatilization from urea raises questions regarding yield performance and efficiency. This study compares the yield and N offtake of grass fertilized with urea, calcium ammonium nitrate (CAN) and urea treated with the urease inhibitor N‐(n ‐ butyl) thiophosphoric triamide (NBPT) at six site‐years. Five annual fertilizer N rates (100–500 kg N/ha) were applied in five equal splits of 20–100 kg N/ha during the growing season. On average, urea produced slightly better yields than CAN in spring (103.5% of CAN yield) and slightly poorer yields in summer (98.4% of CAN yield). There was no significant difference in annual grass yield between urea, CAN and urea + NBPT. Urea had the lowest cost per tonne of DM grass yield produced. However, the urea treatment had lower N offtake than CAN and this difference was more pronounced as the N rate increased. There was no difference in N offtake between urea + NBPT and CAN. While this study shows that urea produced yields comparable to CAN, urea apparent fertilizer N recovery (AFNR) tends to be lower. Urea selection in place of CAN will increase national ammonia emissions which is problematic for countries with targets to reduce ammonia emissions. Promisingly, NBPT allows the agronomic performance of urea to consistently equal CAN across N rates by addressing the ammonia loss limitations of urea.     

添加NBPT/DMPP/CP的高效稳定性尿素在黑土和褐土中的施用效应

  【目的】  研究添加脲酶/硝化抑制剂的高效稳定性尿素在黑土和褐土中的作用效果,为科学合理选择抑制剂提供科学依据。  【方法】  以春玉米为试材,采用东北典型的黑土和褐土进行盆栽试验。供试抑制剂包括N-丁基硫代磷酰三胺 (NBPT)、3, 4-二甲基吡唑磷酸盐 (DMPP)、2-氯-6 (三氯甲基)-吡啶 (CP)。试验设不施氮肥 (U0)、施普通尿素 (U),和在尿素中添加NBPT、DMPP、CP、NBPT+DMPP、NBPT+CP、DMPP+CP,共8个处理。在玉米苗期、大喇叭口期、灌浆期、成熟期取样,测定土壤尿素态氮、NH₄+-N和NO₃–-N含量,计算硝化抑制率,玉米抽雄吐丝后测定棒三叶叶面积和叶绿素含量,收获后测定玉米生物量、氮素含量等指标。  【结果】  1) 与普通尿素 (U) 相比,黑土上添加NBPT+DMPP、NBPT+CP处理玉米苗期土壤中NH₄+-N含量分别提高1.32、0.96倍,NO₃–-N含量分别降低1.35、1.04倍,玉米叶面积增加,叶片叶绿素含量增高。褐土中,添加DMPP+CP处理在玉米苗期土壤NH₄+-N含量提高3.09倍,NO₃–-N含量降低1.49倍,玉米叶绿素含量提高1.61倍,显著高于对照和单一抑制剂处理。2) 在黑土中,与普通尿素相比,添加NBPT+DMPP、NBPT+CP处理的玉米籽粒产量分别增加1.64和2.18倍;氮素表观利用率分别提高3.02和3.34倍,高于其他处理。褐土添加DMPP+CP处理的籽粒产量增加1.41倍,氮素表观利用率提高4.98倍,高于其他处理。  【结论】  在黑土中,尿素配施NBPT+DMPP、NBPT+CP可以有效抑制NH₄+-N向NO₃–-N的转化,增加玉米氮素吸收量,提高氮肥利用率,从而获得较高的产量,是黑土栽培玉米施用氮肥的最佳选择。褐土中,DMPP+CP的硝化抑制率显著高于添加单一抑制剂,有效抑制铵态氮的硝化作用,减少氮素损失,增加玉米氮素吸收量,从而使玉米高产,因此,添加DMPP+CP是制备褐土玉米专用高效稳定性尿素的最好选择。     

15N Fertilizer recovery in different tillage–straw systems on a Vertisol in north‐west Mexico

Tillage and residue retention affect nitrogen (N) dynamics and nutrient losses and therefore nitrogen use efficiency (NUE) and crop fertilizer use, however, there is little information about residual fertilizer effects on the subsequent crop. Micro‐plots with ¹⁵N‐labelled urea were established in 2014/2015 on a long‐term experiment on a Vertisol in north‐west Mexico. N fertilizer recovery (NFR) and the effects of residual fertilizer N for summer maize (Zea mays L.) and the subsequent wheat (Triticum durum L.) crop were studied in three tillage–straw management practices (CTB: conventionally tilled beds; PB‐straw: permanent raised beds with residue retention; PB‐burn: permanent raised beds with residue burning). Fertilizer ¹⁵N recovery rates for maize grain across all treatments were low with an average of 11%, but after wheat harvest total recovered ¹⁵N (¹⁵N in maize and wheat straw and grain, residual soil ¹⁵N) was over 50% for the PB‐burn treatment. NFR was lowest in CTB after two cropping cycles (32%). Unaccounted N from applied fertilizer for the maize crop averaged 120 kg ¹⁵N ha^?1 after wheat harvest. However, more than 20% of labelled ¹⁵N was found in the 0–90 cm soil profile in both PB treatments after wheat harvest, which highlights the need for long‐term studies and continuous monitoring of the soil nutrient status to avoid over‐application of mineral N fertilizer.