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Mineralization of urea, sulphur coated (SCU), neem cake coated urea (NCU) and N-Serve treated urea (NSU) was studied in four important rice growing soils of India, namely, an alluvial soil (Entisol-Fluvent), a black cotton soil (Vertisol-Ustert), two laterite soils (Oxisol-Acrothox) and an acid sulphate soil (Entisol-Sulphaquent) for a period of four weeks at a temperature of 30°C ± 2°C and a water tension of 1/3 bar. Hydrolysis of urea was faster in alkaline alluvial and black cotton soils than in acid laterite and acid sulphate soil. NH4-N content in soil was the highest with N-Serve during the entire period of study. SCU maintained lower NH4-N in soil than urea only during the first two weeks of incubation. N-Serve was much more effective in inhibiting nitrification than neem cake in all the soils. Inhibition of nitrification by neem cake was most at the end of first week in alkaline and at the end of second week in all other soils. Coating of urea with neem cake imparted both slow-release and nitrification inhibiting properties. 相似文献
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Effect of blending urea with pyrite or coating urea with polymer on ammonia volatilization loss from surface-applied prilled urea 总被引：1，自引：0，他引：1
Laboratory studies on a sandy clay loam (Typic Ustochrept) alkaline soil showed that NH3 volatilization loss from surface-applied prilled urea during an 8-dya incubation under aerobic conditions was 27.5% of applied N (400 kg N ha-1) and was reduced to 8.9% when the urea was blended physically with pyrite in a 1:2 ratio; under anaerobic conditions the values for urea and pyrite-urea were 19.3 and 16.9%, respectively. Other treatments tested were urea-gypsum, neemcake-coated urea and polymer-coated urea. A 6% polymer coating showed the least NH3 volatilization under anaerobic conditions and was next best to pyrite-urea under aerobic conditions. A 3% polymer coating was slightly inferior to the 6% coating. Urea-gypsum and neemcake-coated urea did not differ very much from urea alone under anaerobic conditions, but under aerobic conditions neemcake-urea showed a significantly lower total NH3 loss compared to prilled urea alone and urea-gypsum. 相似文献
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A model for predicting the concentration profiles of urea, ammonium and soil pH in a soil column following diffusion from a surface application of urea is developed, using independently derived parameters, and tested experimentally. The following processes within the model were studied separately under the same conditions as those in the diffusion run. The rate of urea hydrolysis as a function of substrate concentration and pH in the soil solution, and the sorption of urea and ammonium by the soil from solution. A theory for the propagation of changes of pH in soils was applied to describe the diffusion of soil alkalinity arising from urea hydrolysis. These processes were linked by three diffusion equations—for urea, NH4 and soil alkalinity, which were solved numerically using finite difference methods. There was good agreement between experimental and predicted concentrations of urea and NH4, and soil pH values at the two times tested. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(9):793-802
Abstract A simple technique for measuring urea release from different coated urea fertilizer materials in simulated wetland soil has been developed and tested. The laboratory soil system used simulates physical, chemical, and microbiological environments of wetland soils under field conditions. Laboratory and field values for urea release are in good agreement. 相似文献
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[目的]利用葡萄糖对尿素改性可延缓尿素水解,提高尿素氮肥利用率.从葡萄糖与尿素的反应特征、产物结构方面,研究其作用机理及葡萄糖添加量对尿素分解的影响.[方法]将葡萄糖按10％的比例加入到熔融尿素中获得葡萄糖改性尿素,利用傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)和液相色谱–质谱联用(LC-MS)分析葡萄... 相似文献
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控释尿素与普通尿素配施在冬小麦上的最佳应用比例研究 总被引：5，自引：4，他引：1
为明确控释尿素与普通尿素配合施用在作物上的应用效果,以冬小麦为研究材料,在田间试验条件下研究了不同比例（0、 10%、 30%、 50%、 100%）的控释尿素（CRU,释放期60 d）与普通尿素配合追施（基追比为3∶7）对冬小麦旗叶叶绿素a含量和净光合速率、 产量、 氮肥利用率、 分蘖情况以及经济效益的影响。结果表明, 控释尿素比例为50% 和100% 处理的冬小麦叶绿素a 和净光合速率在各生育期都保持了较高水平; 与仅施用普通尿素相比,控释尿素为50%的处理的各项指标都明显提高,分蘖数自返青期起保持了较高水平,小麦产量增加了17.0%,氮肥利用率提高了16.73%,增收2587.23 yuan/hm2。综合分析,50%控释尿素的施肥处理在小麦上应用效果最好。 相似文献
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不同量的包膜控释尿素与普通尿素配施在夏玉米上的应用研究 总被引：8，自引：0，他引：8
通过田间试验,研究了释放期为60 d的包膜控释尿素（PCU60）不同用量与普通尿素（U）配合基施对夏玉米产量、氮肥利用率、氮素积累量及经济效益的影响; 并比较PCU60氮素在田间及25℃静水的溶出特征。结果表明: 在施氮量相等的条件下,不同用量PCU60与普通尿素配合基施与习惯施肥相比夏玉米产量显著提高,氮素总积累量、子粒氮素积累量明显增加,氮肥利用率提高5.86%11.39%,净收入增加1303.21715.2 Yuan/hm2; 其中以PCU60氮素占总施氮量30%的经济效益最高。PCU60在田间与在25℃静水中的氮素溶出特征吻合较好; 与普通氮素配合基施氮素释放符合夏玉米的吸氮规律。 相似文献
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Use of urea coated with natural products to inhibit urea hydrolysis and nitrification in soil 总被引：2，自引：0，他引：2
Dharani D. Patra Usha Kiran Sukhmal Chand Mohd. Anwar 《Biology and Fertility of Soils》2009,45(6):617-621
Laboratory incubation experiments were conducted with uncoated urea or urea coated with dementholized oil (DMO), pitch (the
mint oil discard), terpenes (the products of menthol mint oil), or dicyandiamide (DCD) to study the retardation of urea hydrolysis
and nitrification in soil. Two levels (0.5 and 1 %) of coating were tested. Urea was applied at a rate of 200 mg kg−1 of dry weight of soil. The urea hydrolysis and nitrification processes were inhibited by all three natural products. All
the three natural products viz., DMO, terpenes, and pitch significantly retarded urease activity of soil. 相似文献
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控释尿素与普通尿素配施对冬小麦氮肥利用率的影响 总被引：55，自引：12，他引：55
在高肥力麦田中,随着氮肥施用量的不断增加,氮肥利用率下降,单位氮肥的增产量递减。氮素养分的损失不仅造成肥料的浪费,而且给环境带来潜在的威胁。为了提高氮肥的增产效益及氮肥利用率,减少氮肥对环境的污染,采用田间小区试验,研究了控释尿素和普通尿素配施对冬小麦产量、蛋白质含量、氮肥利用率及土壤硝态氮积累量的影响。结果表明,控释尿素与普通尿素配施与普通尿素单施相比,无论是相同施氮量还是减少30%的施氮量,冬小麦子粒产量都极显著增加,而且子粒蛋白质含量明显提高或不降低;同时提高了氮肥利用率,降低了土壤中硝态氮的积累量。 相似文献
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尿素融合葡萄糖对潮土中尿素的水解及相关酶活性的影响 总被引：1，自引：1，他引：0
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Effects of preemergence and postemergence herbicides on urea hydrolysis and nitrification of urea nitrogen in soil 总被引：1，自引：0，他引：1
The influence of 5 and 50 mg active ingredient kg-1 soil of nine preemergence and nine postemergence herbicides on transformations of urea N in soil was studied in samples of two coarse-textured and two fine-textured soils incubated aerobically at 20°C. The effects of each herbicide on soil urea transformations was measured by determining the amounts of urea hydrolyzed and the amounts of NO
inf3
sup-
and NO
inf2
sup-
produced at various times after treatment with urea. Applied at the rate of 5 mg active ingredient kg-1 soil, none of the herbicides retarded urea hydrolysis in the four soils used, but four of the postemergence herbicides (acifluorfen, diclofop methyl, fenoxaprop ethyl) retarded urea hydrolysis in the two coarse-textured soils. All the herbicides tested except siduron retarded nitrification in the two coarse-textured soils when applied at 50 mg of urea N active ingredient kg-1 soil, and fenoxaprop ethyl and tridiphane markedly retarded nitrification of urea N in all four of the soils when applied at this rate. One-way analysis of variance and correlation analyses indicated that the inhibitory effects of the 18 herbicides tested on nitrification of urea N in soil increased with a decrease in the organic-matter content and an increase in the sand content of the soil.
Present address: Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521, USA 相似文献
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不同释放期包膜控释尿素与普通尿素配施在夏玉米上的应用效果研究 总被引：8，自引：0，他引：8
通过大田对比试验研究了释放期为30 d、60 d、90 d的包膜控释尿素(分别用PCU30、PCU60、PCU90表示)与普通尿素(U)配合一次性基施对夏玉米产量、氮肥利用率、氮素积累量及经济效益的影响。结果表明:在施氮量相等、包膜控释氮素占总施氮量30%的条件下,不同释放期的包膜控释尿素(PCU30、PCU60、PCU90)与普通尿素配合一次基施比习惯施肥显著增加夏玉米产量和氮素积累总量,提高氮肥利用率和经济效益,其中PCU60与普通尿素配合一次基施玉米产量最高,为8778 kg/hm2,增产12.0%;氮素积累总量为201.5 kg/hm2,增加18.9%;氮肥利用率提高11.02个百分点;经济效益为11468.7元/hm2,提高产量10.7%。 相似文献
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太湖地区稻麦轮作条件下施用包膜尿素的氮素循环和损失 总被引：8，自引：0，他引：8
A field experiment was conducted to investigate the fate of ^15N-labeled urea and its residual effect under the winter wheat （Triticum aestivum L.） and summer maize （Zea mays L.） rotation system on the North China Plain. Compared to a conventional application rate of 360 kg N ha^-1 （N360）, a reduced rate of 120 kg N ha^-1 （N120） led to a significant increase （P 〈 0.05） in wheat yield and no significant differences were found for maize. However, in the 0-100 cm soil profile at harvest, compared with N360, N120 led to significant decreases （P 〈 0.05） of percent residual N and percent unaccounted-for N, which possibly reflected losses from the managed system. Of the residual fertilizer N in the soil profile, 25.6%-44.7% and 20.7%-38.2% for N120 and N360, respectively, were in the organic N pool, whereas 0.3%-3.0% and 11.2%-24.4%, correspondingly, were in the nitrate pool, indicating a higher potential for leaching loss associated with application at the conventional rate. Recovery of residual N in the soil profile by succeeding crops was less than 7.5% of the applied N. For N120, total soil N balance was negative; however, there was still considerable mineral N （NH4^＋-N and NO3^--N） in the soil profile after harvest. Therefore, N120 could be considered ngronomically acceptable in the short run, but for long-term sustainability, the N rate should be recommended based on a soil mineral N test and a plant tissue nitrate test to maintain the soil fertility. 相似文献
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A model of ammonia volatilization from applied urea. IV. Effect of method of urea application 总被引：1，自引：0，他引：1
Equations are given for calculating the initial distribution when a solute is (a) applied at the surface (b) placed below the surface and (c) mixed uniformly in a given depth of top soil. These equations are plugged into a predictive model developed by the authors (Rachhpal-Singh & Nye, 1986a) to compare the concentration profiles of ammoniacal-nitrogen and soil pH, and ammonia volatilization losses under the three methods of urea application. Placement of urea gave smaller ammonia losses than uniform mixing in the same depth of soil, which in turn gave smaller losses than surface application. Half-time for ammonia volatilization was about 6 days irrespective of the method and depth of urea application. Concentration profiles of ammoniacal-nitrogen and soil pH were more affected by variation in the depth of placement than by depth of mixing. The experimental ammonia volatilization losses and the concentration profiles of ammoniacal-nitrogen and soil pH agreed very well with those predicted by the model. 相似文献
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缓释尿素与普通尿素配施对氨挥发和土壤氮素动态变化过程的影响 总被引：2，自引：1，他引：1
通过室内模拟试验,采用"静态吸收法"和"土壤培养法",研究了缓释尿素与普通尿素混施条件下,氨挥发和土壤中氮素的动态变化特征。结果表明:缓释掺混肥处理能减少氨挥发损失氮量;与普通尿素处理(SRU0)相比,25%缓释尿素+75%普通尿素(SRU25)、45%缓释尿素+55%普通尿素(SRU45)、65%缓释尿素+35%普通尿素(SRU65)、100%缓释尿素(SRU100)处理的氨挥发量分别降低19.88%、25.94%、42.84%和46.13%。在培养前期,普通尿素处理的土壤全氮、碱解氮和铵态氮含量明显高于缓释尿素处理,随着培养时间延长,普通尿素处理降低幅度最大,缓释掺混肥处理的全氮、碱解氮和铵态氮含量明显高于普通尿素处理;而硝态氮含量随培养时间延长逐渐升高。其中,以45%缓释尿素+55%普通尿素配比最佳,既能满足植物全生育期对养分的需求,又能减少氨挥发损失,节省经济成本。 相似文献
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Muhammad Irfan Arshad Hussain Wasif Farooq Munir Hussain Zia 《Journal of plant nutrition》2018,41(13):1625-1635
The research was focused on the synthesis and characterization of zinc (Zn)-coated urea fertilizer. Zinc oxide (ZnO) particles were coated on urea granules through two different coating techniques, i.e., slurry coating and wet coating, and the release rate of the coated Zn was measured up to 24 hours. Slurry coating technique showed better Zn release rate and morphology of coated urea granules as compared with wet coating technique using different binders, i.e., water, molasses, paraffin oil, and the combined mixture of honey bee wax and gum arabica. Urea granules synthesized through wet coating technique have a low amount of Zn as compared with slurry-coated urea granules. Urea granules coated through slurry coating technique and molasses, paraffin oil, and water (MPW) as a binder were the best in term of coating efficiency, uniform size distribution of ZnO-coated particles, granule's morphology, and release rate of Zn from coated formulations. 相似文献
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以聚碳酸亚丙酯（PPC）与聚丁二酸丁二醇酯（PBS）两种可生物降解树脂作为包膜材料,研制不同PPC/PBS组方包膜溶液,铺膜后初步确定两种材料混合的最佳比例;采用流化喷涂分别制备包膜尿素。通过分光光度法研究不同肥料的初期溶出率,采用扫描电镜观察包膜结构。结果表明,PPC与PBS的质量比在7∶5时,材料之间融合较好,质地较柔软,适合作为肥料包膜材料。实验证明此包膜材料在尿素表面能够形成细腻光滑致密的膜,可以适应尿素颗粒表面的外形轮廓而将其紧密覆盖。尿素包膜后,对尿素氮的释放有明显的控释作用,且在一定范围内,减少包膜所用时间或增加树脂用量都能增强控释效果。 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(9-10):1595-1606
Abstract The fate of nitrogen (N) has been studied under several agronomic crops and agricultural profiles, but relatively little information has been collected from areas managed as turfgrass. The turfgrass industry has become the focus of environmental concerns in recent years and is often identified as a source of ground water contaminate. The objectives of this study were to: i) investigate the hydrology of 20‐cm diameter by 50‐cm deep undisturbed soil columns covered with a Kentucky bluegrass (Poa pratensis L.) turf under a heavy (one 2.54‐cm application) and a light (four 0.64‐cm applications) irrigation regime, and to ii) quantify the fate of 15N‐labeled urea when it is applied to an undisturbed soil columns having intact macropores. Clipping, verdure, and thatch/mat samples were taken from each column, and the soil was excavated in 10‐cm layers at the end of the 7‐day test period. A glass collection chamber was used to collect volatilized N and a plastic bag for leachate collection. All samples were analyzed for atom % 15N. Volatilization of N was negligible because irrigation was applied immediately after the application of N. The heavy irrigation regime significantly increased the transport of N below 30 cm by five times, compared to the light irrigation regime. Eighty‐five percent of the N found in the leachate from the 50‐cm columns was in the urea form indicating that macropores may have played a major role in transport of surface applied N through the soil profile. 相似文献