A novel urea coated with pine oleoresin for enhancing yield and nitrogen uptake by maize crop

A study was conducted with maize in Vertisol, Inceptisol, Alfisol and Aridisol to evaluate the efficacy of the pine oleoresin coated urea fertilizers (coated with 1.25, 2.50, 3.75 and 5.00% pine oleoresin). Significant increase in biomass yield was observed in all the soils when urea was coated with pine oleoresin at 3.75% or more. All the pine oleoresin coated urea in Inceptisol and Aridisol; and 3.75% and 5% pine oleoresin coated urea in Vertisol and Alfisol significantly increased nitrogen (N) uptake as compared to uncoated urea. Nitrogen use efficiency increased from 19.34% to 32.80% in Vertisol, 13.06% to 28.27% in Alfisol, 13.87% to 23.86% in Inceptisol and 10.68% to 20.23% in Aridisol, as a result of coating urea with pine oleoresin. Thus the results indicate that there is a beneficial effect of coating urea with pine oleoresin with respect to yield, N uptake and use efficiency in maize crop.     

Influence of rates and sources of nitrogen on growth,nitrogen uptake and yield of cotton (G. hirsutum L.)

Field experiments on cotton with different forms of urea applied at rates of 40 and 80 kg N/ha were carried out. The results indicated that application of nitrogen increased plant height, dry matter accumulation, number of bolls per plant, seed cotton yield and nitrogen uptake. The proportion of dry matter and nitrogen in the stem was increased and that in the leaves was reduced by N application. Sulphur coated urea (all applied at sowing) was about the same in effect as N-Serve treated urea and gave significantly more seed cotton yield than untreated urea, neem cake treated urea and sulphur coated urea (applied in two splits). Nitrogen efficiency as expressed by kg seed cotton production per kg N applied was greater with 40 kg N/ha rate than with 80 kg N/ha. Sulphur coated urea (all applied at sowing) gave the highest nitrogen efficiency followed by N-Serve treated urea.     

Effect of nitrogen levels and coated urea on growth,yields and nitrogen use efficiency in aromatic rice

Results from a field experiment conducted at the Indian Agricultural Research Institute, New Delhi, India showed that coating urea with elemental sulfur or gypsum or phosphogypsum gave higher yields (12.08, 6.78 and 6.14% higher grain yield compared to prilled urea) of high yielding an aromatic rice cultivar ‘Pusa Sugandh 5’ (Pusa 2511) and increased the efficiency of prilled urea. As regards nitrogen use efficiency sulfur coated urea was nearly twice as effective as gypsum or phosphogypsum coated urea; the latter two were equally effective compared to prilled urea alone.     

Crop yield and soil nitrogen dynamics in an intermittently flooded rice field affected by nitrification inhibitors

A field experiment was conducted to study yield and soil N dynamics in an irrigated, intermittently submerged rice field at New Delhi, India, where chemically synthesized as well as neem derived urea coating nitrification inhibitors with prilled urea were applied. Rice (var. IR-32) was grown on a Typic Ustochrept alluvial soil. No nitrogen (control), prilled urea alone, prilled urea mixed with dicyandiamide (DCD), neem (powdered Azadirachta indica Juss. seeds) coated urea and Nimin (commercial derivative of neem) coated urea were tested for their efficacy in regulating yield and conservation of N. None of the inhibitors could increase biomass or grain yield over urea. But all the inhibitors were able to conserve soil ammonium and DCD was the most efficient nitrification inhibitor followed by Nimin coated urea. N-uptake, recovery, physiological and agronomic efficiencies were highest in urea treated plots. The performances of all the inhibitors were against the popular trend where crop yield and N-uptake were enhanced by their application. But, more studies are required on the performance of these inhibitors in rice fields to come to a stronger conclusion.     

Rice responses to single application of coated urea on yield,dry matter accumulation,and nitrogen uptake in Southern China

Nitrogen is the most important element for rice (Oryza sativa L.) growth. However, excessive use of conventional urea leads to serious environmental problems in China. The objective of this study was to evaluate the release patterns of coated urea and response of rice to coated urea on dry matter accumulation, nitrogen uptake, and nitrogen use efficiencies on a clay soil. A two single-year experiment was carried out in southern China to evaluate two coated urea, polymer-coated urea (PCU) and polymer-sulfur coated urea (PSCU). Nitrogen (N) release patterns of PCU and PSCU were determined in the laboratory and in the field. The release rate of PSCU in the field was much higher than that in the laboratory. And PCU had a similar release pattern both in the field and laboratory. Compared with urea, rice fertilized with PCU and PSCU had similar dry matter accumulation, but higher grain yield and N use efficiencies. Recovery efficiency of PCU treatment reached 50% in 2012 and 60% in 2013, around 40% for PSCU, which was only 16% for single application of urea.     

包膜尿素对芹菜产量、品质及氮素平衡的影响

通过盆栽试验研究了包膜尿素(自制)和尿素等肥料在两种质地灰潮土上对芹菜产量、品质、氮素吸收和氮平衡的影响。结果表明,施用包膜尿素较尿素使当季芹菜增产11.5％-15.2％,氮素吸收增加5.9％-9.5％,氨挥发损失N减少14.2％-14.9％,淋失和反硝化氮损失减少25.5％-28.3％,氮素利用率提高19.2％-27.1％,土壤持留氮增加32.0％-37.3％。芹菜植株硝态氮含量降低44.2％-58.9％,维生素C含量显著提高,品质改善;后茬作物生菜增产14.4％-35.2％。     

延迟释放型包衣尿素对水稻生长和氮素吸收的影响

通过田间试验比较研究了普通尿素和延迟释放型包衣尿素在不同施用量、不同施肥方式(普通尿素为基肥+两次追肥;延迟释放型包衣尿素为接触施肥方式)条件下对移栽稻生长过程和氮素吸收的影响。结果表明,延迟释放型包衣尿素在比普通尿素施氮量(N150kg/hm2)减少30%(N105kg/hm2)和50%(N75kg/hm2)时,对水稻生长不会产生任何不良影响;由于包衣尿素在田间的养分释放动态与水稻对氮素的吸收规律吻合,施用包衣尿素的水稻产量、吸氮量和氮肥利用率均显著高于普通尿素处理,其中水稻产量增加12.7%～14.4%,吸氮量增加27.5%～32.7%;普通尿素和氮肥用量减少30%和50%的包衣尿素3个处理的氮肥利用率分别为19.9%、58.8%和89.9%。此外,施用包衣尿素比普通尿素水稻的子粒粗蛋白质含量提高9.2%～12.2%。     

EFFECT OF NEEM-OIL COATED PRILLED UREA WITH VARYING THICKNESS OF NEEM-OIL COATING AND NITROGEN RATES ON PRODUCTIVITY AND NITROGEN-USE EFFICIENCY OF LOWLAND IRRIGATED RICE UNDER INDO-GANGETIC PLAINS

The nitrogen (N) fertilizer-use efficiency (20–50%) is low in rice fields in India. The neem-oil coated urea can increase N-use efficiency in lowland rice, but the desirable thickness of neem-oil coating onto urea is not known yet. Therefore, field experiments were conducted during kharif (rainy) season years 2004 and 2005 at the Research Farm of Indian Agricultural Research Institute, New Delhi to know the suitable thickness of neem-oil coating on prilled urea (PU) for increased N-use efficiency and yield. The treatments comprised of twelve combinations of four N sources (PU coated with neem-oil thickness of 0, 500, 1000 and 2000 mg kg^?1 PU) and three N levels (50, 100, and 150 kg N ha^?1) plus a no-N control. Prilled urea (PU) refers to the common urea available commercially in prills, which is different from urea super granules. Application of urea coated with neem-oil thickness of 1000 mg kg^?1 PU resulted in significantly higher growth, yield parameters, grain yield, N uptake, and efficiency of aromatic rice (Oryza sativa L.) over uncoated PU. Nitrogen application at 122 kg ha^?1 was optimum for increased yield of rice. Nitrogen-use efficiency decreased significantly and substantially with each successive increase in levels of N from 50 to 150 kg ha^?1.     

Spatial and temporal distribution of nitrogen in a puddled rice soil following application of urea-based fertilizers by different methods

Summary Field experiments were conducted on transplanted rice (Oryza sativa L., var. Ratna) in a submerged soil, in order to study the distribution of N applied at 100 kg/ha. N was introduced as prilled urea or neem cake coated urea broadcast on the soil, and as urea supergranules, 1 or 2.5 g in size, point-placed at 5 cm depth. The surface-broadcast N was found mostly in the top 0–5 cm layer of soil and there was only a small vertical movement of applied N to 5–10 cm depth. With point placement of 1-g urea granules, the fertilizer N was found mostly at 5–10 cm depth and within 2.5 cm horizontal distance from the point of placement, compared with 5–10 cm depth and within 5 cm horizontal distance from the point of placement for the 2.5-g granules. With the two broadcast applications, the NH₄ ⁺-N content reached peaks of 40–68 mg/kg soil in the top 0–5 cm of soil within the first 3–6 days, decreased at a faster rate from the 6th to 12th day and then at a slower rate up to the 32nd day. In contrast, the NH₄ ⁺-N content around the points of placement of the urea supergranules reached peaks of 570–900 mg/kg soil during the first 3–12 days after placement, then decreased rapidly during the next 6–9 days, after which the values remained more or less unchanged but were still higher than the untreated control value.     

氮肥用量与运筹对水稻氮素吸收转运及产量的影响

应用15N示踪技术研究了大田条件下氮肥用量与运筹对水稻氮素吸收、转运及籽粒产量的影响。试验分别设置3个氮肥水平(0、150和240 kg/hm2N)和两种基追比例(即基肥:蘖肥穗粒肥分别为40%︰30%︰30%(A)和30%︰20%︰50%(B)),共5个处理,依次记作N0、N150A、N150B、N240A、N240B。结果表明,在0~240 kg/hm2范围内,提高氮肥水平,显著增加水稻吸收的肥料氮素、土壤氮素数量以及肥料氮在土壤中的残留量。成熟期高氮处理(240 kg/hm2)水稻吸收的肥料氮素、土壤氮素及肥料氮在土壤中的残留量较多,分别为110.25、65.91、32.69 kg/hm2,而氮素的吸收利用率和土壤残留率下降,氮素损失率增加。在相同的氮肥水平下,采用基肥蘖肥穗粒肥比例为30%︰20%︰50%时,水稻吸收的肥料氮数量显著增加,氮素吸收利用率和土壤残留率提高,氮素损失率降低。适量施氮并增加穗粒肥的施氮比例,可以显著增加水稻产量。在本实验条件下,施氮量为240 kg/hm2及基肥蘖肥穗粒肥为30%︰20%︰50%的施氮处理是兼顾产量和环境的最佳氮肥运筹方式。     

控释肥料提高氮素利用率的作用及对水稻效应的研究

研究了田间条件下控释肥料氮的释放速率与水稻吸收氮量之间的关系。结果表明 ,控释肥料氮的释放速率在水稻生育前期高 ,但随着时间的进程而逐渐降低。水稻从 70日型控释肥料中吸收的氮遵循三次曲线 ,因此 70日型控释肥料能够满足水稻本田生长期对氮的需要。施用控释肥料的水层含氮量极低 ,且无可见的水藻生长 ;而施尿素的水层则尿素N和NH4+-N含量高 ,水藻活动繁茂 ,滞留于水层的肥料氮 5～ 6d内迅速地降至无氮对照水平 ,氨的挥发损失和氮的反硝化损失大。控释肥料氮的利用率高达 72.3% ,比尿素高出 36.5个百分点。     

包膜尿素对夏玉米产量、吸氮量和氮分配的影响

以施氮量调控氮代谢,提高氮肥利用率为目标,利用15 N研究了包膜尿素（CU100、150和225kg/hm2）和普通尿素（150和225kg/hm2）对夏玉米产量、生物量、氮肥利用率以及各器官氮分配的影响。结果表明：包膜尿素比普通尿素显著增加玉米从肥料中的吸氮量,显著增加地上部生物量;15N包膜尿素肥料利用率（15NU...     

有机无机配施对水稻产量及氮肥残效的影响

为揭示有机无机配施条件下15N尿素在稻田土壤中的残效状况,在我国北方棕壤性水稻土上进行盆栽试验,结合土壤氮素供应及水稻对肥料氮的吸收利用,探寻最佳的施肥方式.设置空白(CK)、尿素(N)、秸秆+尿素(NS)、猪粪+尿素(NM)、稳定性尿素(NI)、秸秆+稳定性尿素(NIS)、猪粪+稳定性尿素(NIM)7个处理.结果 表...     

缓释尿素与普通尿素不同配比对玉米氮代谢酶和氮素利用的影响

为解决我国西南地区玉米氮肥一次性施用问题,以普通尿素和包膜缓释尿素为供试材料,设置5种普通尿素与缓释尿素配比试验处理,分别为100%缓释尿素(CRU100),75%缓释尿素+25%普通尿素(CRU75),50%缓释尿素+50%普通尿素(CRU50),25%缓释尿素+75%普通尿素(CRU25)和100%普通尿素(CRU0),以不施氮肥(CK1)和常规施肥(CK2,普通尿素60%基施+40%大喇叭口期追施)为对照,研究氮肥一次底施下缓释尿素与普通尿素不同配比对玉米氮代谢关键酶、干物质积累、氮积累及氮素利用的影响。结果表明:(1)施氮显著提高了玉米叶片氮代谢关键酶(谷氨酸合成酶GOGAT和谷氨酰胺合成酶GS)活性,与常规施肥相比,普通尿素与缓释尿素配施可提高叶片GOGAT和GS活性,其中以CRU50和CRU75的缓释尿素比例处理最好。(2)CRU50和CRU75的缓释尿素比例可改善吐丝前、后物质积累和氮素积累,显著提高成熟期物质积累量和氮素积累量。(3)随缓释尿素比例增加,玉米穗粒数、千粒重和产量及氮收获指数均呈先升后降的趋势;掺施缓释尿素处理产量较常规施肥处理平均增产4.46%,其中CRU50和CRU75处理产量最高,收获指数和氮肥表观利用率显著高于其它处理。因此,普通尿素掺混50%~75%比例的缓释尿素进行一次底施,既能增加玉米产量,又可实现氮素的高效利用。     

黄腐酸和聚天冬氨酸对蕹菜氮素吸收及氮肥去向的影响

为了解黄腐酸(FA)和聚天冬氨酸(PASP)对蕹菜氮素吸收及氮肥去向的影响,采用15N尿素示踪技术,设置不施氮肥(CK),单施尿素(N),尿素配施低、中、高用量的FA和PASP(NF1、NF2、NF3、NP1、NP2、NP3)8个处理,在温室条件下进行盆栽试验。结果表明,与N处理相比,配施FA和PASP后蕹菜地上部鲜重增加了7.46%~17.55%;NP2、NP3和各NF处理显著提高了蕹菜的吸氮量,提高幅度为10.84%~18.25%,其中,蕹菜对非标记氮的吸收量显著增加,且随FA和PASP用量的增大而增加;NF3处理的15N利用率显著低于N处理,其余处理无显著变化;NF2、NF3、NP2和NP3处理的15N损失率比N处理减少了5.41~14.58个百分点;NF2、NF3和NP2处理的15N土壤残留率增加了5.08~20.02个百分点。研究表明,中、高用量的FA和PASP与尿素配施促进了蕹菜对氮素(尤其是非标记氮素)的吸收,同时减少了氮肥的损失,增加了氮肥在土壤中的残留,对土壤氮库的贡献作用显著。     

Assessment of urea coated with pomegranate fruit powder as N slow-release fertilizer in maize

It has been hypothesized that plant polyphenol plus lignin, cellulose, and hemicelluloses can immobilize/remineralize inorganic fertilizers, such as urea, better than polyphenol alone. To test this hypothesis, urea was coated with pomegranate (Punica granatum L.) fruit powder (containing polyphenol+lignin+cellulose) at rates of 0%, 30%, 70%, and 100% (w/w) of fertilizer urea. Fertilizer nitrogen was applied at 100 and 200 mg kg^?1 soil in a clay loam soil. This natural coating material, particularly at the rate of 100% (w/w), improved the distribution of mineral nitrogen (N) and available phosphorus (P) in soil during both early and advanced growth stages of maize and significantly increased total crop N and P uptake at both rates of fertilizer nitrogen compared to urea alone. The results suggest that urea coated with the powder of pomegranate fruit could potentially be an N slow-release fertilizer for use in better synchronizing crop N demand with soil N supply.     

基于临界氮浓度的水稻氮素营养诊断研究

【目的】 依据水稻品种的氮素营养特征计算其氮营养指数 (NNI) 和氮素亏缺 (N_and) 值,可实现作物氮素状况的精确定量调控。本研究比较了杂交稻和常规稻在不同氮水平下的NNI和N_and值,为该诊断方法的精准使用提供依据。 【方法】 本研究选用超级杂交稻 (Y两优一号、超优千号) 和常规稻 (粤农丝苗、金农丝苗) 为对象进行田间试验。设施氮水平0、40、80、120、160、200、240 kg/hm2(分别以N0、N40、N80、N120、N160、N200、N240表示),分析测定了水稻移栽后15、30、45、60、75天和成熟期地上部干物质量及其氮浓度,构建临界氮浓度变化曲线,利用该曲线计算了不同品种在不同时期的临界氮浓度、氮营养指数和氮亏缺值。 【结果】 杂交稻地上部干物重在N0、N40、N80、N120、N160处理间差异显著,N200、N240处理间差异不显著,但显著高于其他处理;常规稻地上部干物质重在N0、N40、N80、N120处理间差异显著,N160、N200、N240处理间差异不显著,但显著高于N0、N40、N80、N120处理。水稻植株氮浓度均随着施氮水平的提高而增加,但随生育期的延长和地上部干物重的增加,水稻植株氮浓度均呈下降趋势。根据地上部干物质重与其氮浓度变化关系构建水稻临界氮浓度 (Nc) 变化曲线,杂交稻为N_c=3.36DM–0.31(R2=0.91),常规稻为N_c=2.96DM–0.25(R2=0.86)。基于临界氮浓度曲线,计算不同水稻品种的NNI和N_and,其中杂交稻和常规稻NNI变化范围分别为0.73～1.05和0.78～1.11,N_and变化范围分别为–9.8～117.8 kg/hm2和–25.4～90.3 kg/hm2。 【结论】 常规稻品种临界氮浓度高于相同生育期的杂交稻品种,但杂交稻的干物质量生产能力大于常规稻。在本试验条件下,依据N_and计算结果,杂交稻临界氮浓度下的氮素积累量大于常规稻,其中杂交稻和常规稻适宜施氮量分别为200 kg/hm2左右和160～200 kg/hm2。      

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

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.     

Dynamics of dry matter and nitrogen distribution in transplanted rice on mollisols

We studied the dynamics of dry matter (DM) and nitrogen (N) distribution in different plant parts (leaf, stem, and panicle) and grain yield of transplanted rice due to N management practices through neem coated urea (NCU). The results indicated that application of NCU at 125% recommended dose of N (RDN) with 50:25:25 split schedule at basal (B), active tillering (AT), and panicle initiation (PI) stages resulted in higher DM and N distribution to leaf, stem, and panicle at 60 and 90 days after transplanting and harvest than the application of prilled urea at 100% RDN with the same split schedule (existing practice). Further, the increment in grain yield was 10.95% than the existing practice. Hence, we suggest the application of NCU at 125% RDN with 50:25:25 split schedule at B, AT, and PI stages for achieving higher DM and grain yield on Mollisols.     

施用包膜尿素对水稻生长和氮磷流失的影响

施用新型肥料是减少养分径流损失的重要途径。采用田间试验研究了施用包膜尿素对水稻生长和径流氮磷损失的影响,试验设置CK(习惯施肥)、PU1(减磷41%、减氮20%、施普通尿素)、PU2(PU1基础上减氮13%)、UR1(PU2基础上施包膜尿素)和UR2(UR1基础上减氮13%)5个处理。结果表明:PU1和UR1处理水稻氮磷含量与CK处理相近,PU1成熟期氮、磷总积累量比CK增加11.21,2.69kg/hm~2。PU1和UR1处理成熟期地上部生物量和籽粒产量高于CK处理,籽粒产量分别提高7.68%,5.77%。PU1、PU2、UR1和UR2处理径流总磷含量和累积流失量比CK处理低,减少13.18%~21.51%。施用包膜尿素(PU1、PU2)处理径流总氮、铵氮和硝氮含量低于施用普通尿素(CK、UR1、UR2)处理;稻田径流总氮、铵氮和硝氮累积流失量分别减少12.90%~26.91%,54.52%~49.38%和4.03%~15.95%,其中包膜尿素处理铵氮累积流失量显著(P0.05)小于普通尿素处理。施用包膜尿素和优化施肥能促进水稻对氮磷养分的吸收,提高水稻籽粒产量,显著减少稻田氮磷流失量,值得在水稻生产中推广应用。