Relative Efficiency of Prilled Urea, Urea Super Granules, Sulphur Coated Urea and Nitrification Inhibitor N-Serve Blended Urea for Direct Seeded Rice

A two year field study conducted at the Indian Agricultural Research Institute, New Delhi, India showed that for direct seeded rice (drilled in moist bed) blending of urea with nitrification inhibitor N-Serve was the most advantageous; it gave significantly higher grain and straw yield nitrogen uptake by rice than urea super-granules (USG), urea briquettes (UB), sulphur coated urea (SCU), neem cake coated urea (NCU) and prilled urea. USG or UB were next in order and significantly superior to SCU, NCU and prilled urea, which were equally effective. Nitrogen application to rice left a significant residual effect on succeeding wheat, but various sources of nitrogen studied did not differ significantly in this respect.     

硫包衣尿素对水稻养分吸收利用及土壤反应的影响

采用盆栽结合部分大田论证的试验方法,研究了硫包衣尿素(SCU)和常规尿素对水稻生长、营养元素吸收利用及增产效应和土壤反应的影响。结果表明:大田上SCU和常规尿素处理其产量分别是对照的1.20,1.11倍,盆栽试验下为对照的1.92,1.48倍;施肥量相同的SCU处理水稻产量比常规尿素处理增加10.93%~22.23%,SCU提高水稻产量的优势在于千粒重;同常规尿素相比,SCU促进了水稻对磷的吸收,对钾的影响不大。盆栽试验表明,施常规尿素和SCU的处理氮收获指数都随施氮量的增加而增加,等N量(N 0.15 g/kg土)和等施肥量(0.66 g/kg土)下,SCU处理其氮收获指数显著高于对应的常规尿素处理,施用SCU的处理其氮素的利用率也比常规尿素提高11.79%~20.25%,其氮肥利用率最高达57.58%;短期内适宜施氮量下SCU未降低土壤pH,但随着SCU施用量的增加,土壤酸化明显,且趋势超过常规尿素。     

不同质地土壤下缓释尿素与常规尿素配施对水稻产量及其生长发育的影响

以早熟晚粳南粳44为材料,分别在2种质地的土壤上,研究270 kg hm^-2施氮条件下, 2种缓释尿素(硫包衣尿素SCU)单施及与常规尿素(PU)按2种不同比例混配一次性基施对水稻产量及其生长发育的影响。结果表明,与PU分施相比,SCU2单施与SCU1+PU(1∶1)、SCU1+PU(2∶1)及SCU2+PU(2∶1)配施处理水稻产量、生长中后期氮素吸收量、氮素吸收利用率与偏生产力、干物质积累以及茎鞘可用性糖颖花比均显著提高,抽穗后期根系α-萘胺氧化量维持较高水平,下降幅度小;产量、氮素吸收量、氮肥吸收利用率、偏生产力及干物质积累量在黏土上略高于在沙土上;抽穗期与抽穗后10 d根系α-萘胺氧化量在黏土上低于在沙土上,抽穗后20 d、30 d在两种土上差异不大。SCU单施及与PU配施基本上能满足水稻生长需求,SCU1与PU配施效果明显优于单施;SCU2单施效果最佳,SCU2+PU(2∶1)次之,SCU2+PU(1∶1)效果不显著。     

Integrated Nitrogen Management with Green Manures in Rice-Chickpea Cropping System

A field experiment was conducted during wet and dry seasons of 1987–88 and 1988–89 to evaluate the performance of green manures with and without fertilizer nitrogen in lowland rice and their residual effect on succeeding crop of chickpea grown under rice-chickpea cropping system. Incorporation of Ipomea carnea (green leaves), Cassia tora and Parthenium hysterophorus (green young plants) ca. 5 t/ha fresh weight significantly improved yield and yield components namely panicles per hill, panicle length, grains per panicle and test weight of transplanted rice. The results showed that at least 20 kg/ha fertilizer nitrogen applied to rice could be replaced by incorporation of 5 t/ha fresh weight green manure. Supplementation of 60 kg N/ha through urea to the green manures treated plots proved to be the best in respect of grain yield and was comparable to the yield obtained under 80 kg N/ha as urea alone. Plant N-uptake followed the similar pattern of rice grain yield. Residual fertility in terms of available nitrogen increased under the green manure treatments, whereas urea nitrogen alone made no impact on fertility build-up. Green manures showed significantly higher residual response than fertilizer N alone to seed yield and N uptake of chickpea.     

Straw management, crop rotation, and nitrogen source effect on wheat grain yield and nitrogen use efficiency

Nitrogen fertilizer management from different sources and annual crop rotations are important components of wheat (Triticum aestivum L.) production systems, especially where air and soil quality issues have prompted a search for alternatives to wheat straw burning. This study examined the effects of two different wheat straw management options (burning and incorporation by tillage), three crop rotations [wheat-sesbania (Sesbania spp.), wheat–maize (Zea mays L.), and wheat-clean fallow] and three N sources (urea, chicken manure, and urea plus chicken manure) on wheat grain yield and N use efficiency. The experiment was conducted as split–split plot treatment arrangement with three replications for eight wheat cropping seasons in the state of Sonora, Mexico. Results indicated that both wheat grain yield and N use efficiency were higher with burning than incorporation of wheat straw and with fertilization with urea or urea plus chicken manure than chicken manure alone. As shown by the crop rotation-by-straw management interaction, planting sesbania following incorporation of the straw by tillage produced comparable grain yields to straw burning treatment. In contrast, wheat in annual rotation with maize produced the lowest wheat grain yield and N use efficiency irrespective of the wheat straw management and N source applied.     

硫包衣尿素在夏玉米上的应用效果研究

为了了解硫包衣尿素在夏玉米上的应用效果,充分的发挥肥料作用,通过田间试验,研究了硫包衣尿素和普通尿素不同用量、不同施肥方法（普通尿素为基肥＋1次追肥;硫包衣尿素为一次性基施）对夏玉米出生长、产量、氮肥表观利用效率等的影响。结果表明：硫包衣尿素以等氮量或减量30%采取一次性施肥的方式,夏玉米的生长和产量与普通尿素当地习惯施肥无显著差异,其产量分别达到了10789.17 kg/hm2、10595.11 kg/hm2;在夏玉米上应用硫包衣尿素可显著提高肥料的利用效率和农学效率,其中硫包衣尿素减量30%处理氮肥表观利用率和生产率分别达到了42.59%和20.74kg/kg。硫包衣尿素以一次性基施的施肥方式替代普通尿素基肥加追肥是可行的,能达到省工、节肥、增效的目的。     

四川省农作物种植结构与气候变化耦合协调性研究

为了探究四川省作物种植结构与气候变化的协调关系,本研究基于四川省气候数据与农作物播种面积数据,分析了2000—2018年四川气候变化、农作物种植结构变化以及它们之间的协调关系。结果发现：四川省2000—2018年间降水量、≥10℃积温均呈显著上升趋势,降水量气候倾向率为53.5 mm/10 a,≥10℃积温气候倾向率为123.7℃/10 a;作物播种面积明显增加的有玉米、油料作物、豆类、果园,薯类播种面积保持相对稳定状态,作物播种面积明显下降的有水稻、小麦和其他作物;各主要农作物种植结构占比变化明显。四川省农作物种植占比前三种为水稻、玉米和薯类,多年平均占比分别为21%、17%和13%,且水稻在所有种类中占比较稳定;小麦种植占比正在逐年降低。四川省2000—2018年农作物种植结构变化与气候变化整体相互适应,耦合度与耦合协调度均较高。     

气候变化对中国主要作物生育期的影响研究进展

作物生育进程受环境直接影响,其中气候条件是主要的影响因子之一。本文基于中国粮食主产区分布,阐述了历史气候变化对小麦、玉米和水稻生育期的影响。结果表明,气候变化使北方冬麦区小麦播期推迟,传统品种生育期缩短;西北区冬麦越冬死亡率降低,水分利用率提高,但全生育期缩短。东北区春玉米适宜播期提前,近50年来潜在适宜生长期延长10天左右,晚熟玉米面积增加;华北区小麦-玉米一年两熟适宜生育期延长,推动了小麦—玉米“两晚技术”发展;西北区玉米整体播期提前,灌区玉米全生育期延长,旱区生育期缩短。长江中下游稻区水稻生育期普遍提前,除东北区水稻生育期延长约3天/10年,其他地区水稻全生育期基本呈缩短趋势。总体而言,气候变暖使生产中作物春季适宜播期提前,秋季适宜播期推迟,生产中传统作物品种生育期普遍缩短。通过品种选择和播期调整,可以充分发挥热量资源潜力,规避关键生育期灾害风险,并通过延长作物生长期提高产量。     

Vorfruchtwirkungen verschiedener Blattfrüchte auf Winterweizen und Einfluß von Anbaumaßnahmen

Effects of preceding "break crops" on winter wheat and influence of cultural practices
Between 1979—83 there was tested the effect of 5 "break crops" (biennial alfalfa, clover-grass, faba bean, winter-rape, silomaize) on succeeding winter wheat and the interaction with changed cultural practices such as N-fertilization and conventional or reduced primary tillage (plough ↔ rotary tiller).
After the break crops wheat yield decreased within a range of 4 dt/ha as follows: alfalfa → beans → rape/ clover-grass/maize. Raising N-fertilization hardly allowed to improve the value of the break crops; most likely that of maize and with rotavating. Adaption of N-dressings promised greater influence.
The manner of primary tillage exerted stronger influence on the yield than the level of N-fertilization. Concerning long-term yield the rotary tiller equaled the plough after 4 break crops; after faba bean it was superior. Increasing N-fertilization tendentially favoured the rotary tiller after bean, rape and maize. Using the rotary tiller, at beginning of growth there may be calculated on 15 % higher NO₃-values and/or higher N-mineralization or N-transformation.
Eyespot disease could not be prevented sufficiently and purposefully by an other break crop, N-fertilization or primary tillage. Recurrent rotavating suppressed weed less than ploughing.     

江苏省粳稻-小麦周年高产高效栽培技术研究

为充分挖掘稻麦周年高产潜力,通过不同生态区稻麦两熟多项生产技术试验,研究提出江苏各地粳稻一小麦周年高产的最适播（栽）收期与茬口衔接、最适播栽方式、最适群体起点（密度）以及适宜的肥料运筹、水分管理等栽培技术。     

不同水分条件下缓/控释氮肥对水稻干物质量和氮素吸收、运转及分配的影响

为探究缓/控释肥在不同水分条件下提高氮素利用率及增产机制。本研究以杂交中稻F优498为试验材料,在180 kg hm^-2施氮量基础上,采用两因素裂区设计: 主区设控灌、干湿交替灌溉、传统灌水灌溉3种水分管理方式,副区设尿素一道清、尿素常规运筹、硫包膜缓释肥、树脂包膜控释肥4种氮肥种类,研究缓/控释肥和水分管理方式对水稻干物质量和氮素吸收、运转、分配和产量的影响及其互作效应。结果表明, 缓/控释肥和水分管理方式对水稻主要生育期干物质量和氮吸收、转运、分配及产量具显著影响及互作效应,产量构成因素与氮素在结实期转运总量及其分配呈显著正相关。干湿交替灌溉和缓/控释肥均能提高干物质量、氮素吸收及产量并表现出显著互作效应,施用缓/控释肥氮素表观利用率达42%~53%,相较于尿素一道清和传统的尿素常规运筹,氮肥偏生产力提高6%~23%,氮素农学利用率提高26%~71%,增产8%~19%。控灌条件下,缓/控释肥处理氮素有效性高,保证足穗、促进重穗;干湿交替灌溉条件下缓/控释肥处理能保持氮素的高效释放,有利于高产群体的形成,从而提高稻株氮素积累、协调氮素分配;淹水灌溉条件下,缓/控释肥处理无效分蘖减少,氮素入渗、淋溶降低,成穗率提高。综合产量与氮素吸收、运转的表现,干湿交替灌溉条件下施用缓控释肥为本试验最佳处理,能有效提高氮素利用率,促进高产形成。     

Maximizing Sugarcane Yield by Increasing Plant Population Density, Minimizing NO3-N Leaching and Improving Soil Organic Matter in Different Crop Rotations

In a field experiment conducted during 1992–95 at Lucknow, India, sugarcane was planted in rows 60 and 90 cm apart in three crop rotations (rice-sugarcane-ratoon, Sesbania aculeata for green manure-sugarcane-ratoon, and cowpea-sugarcane-ratoon) with 0, 150 and 300 kg N ha⁻¹ as urea either with or without farmyard manure (FYM) at 10 t ha⁻¹. Sugarcane yields were significantly greater in the Sesbania rotation than in the other because of a larger N uptake. N uptake of the crop was significantly affected by soil organic carbon, and available N and K contents. Ratoon yields, however, were largest in the cowpea sequence followed by the rice rotation, probably due to a prolonged residual effect of cowpea and rice root residues. The residual effect of a Sesbania green manure was negligible as demonstrated by the low NO₃-N content of the soil profile after sugarcane harvest compared to the other two crop sequences. The total cane productivity (main sugarcane plus ratoon) was greater (156 t ha⁻¹) in the cowpea rotation than the Sesbania (152 t ha⁻¹) and rice (140 t ha⁻¹) rotations.     

A spatially explicit crop planting initiation and progression model for the conterminous United States

The ability to accurately estimate crop planting date and planting progression has major implications in crop management, crop model applications, and in developing adaptation strategies for future climate change. The objectives of this study are: 1) identify major factors that determine planting initiation and progression of six major crops in the U.S. and 2) develop a spatially explicit planting initiation and progression model. The crops that were evaluated are maize (Zea mays), cotton (Gossypium hirsutum), rice (Oryza sativa), sorghum (Sorghum bicolor), soybean (Glycine max), and winter wheat (Triticum aestivum). County-level daily planting data from 2005 to 2015 for representative states were obtained from USDA Risk Management Agency. For the five summer crops, the earliest planting gradually shifts to later dates with increasing latitude and elevation. The trend is reversed for winter wheat, with planting initiation shifting to earlier dates from south to north and from low to high elevation. A minimum planting temperature threshold was established for the five summer crops, which decreases from south to north and from low to high elevation. A maximum planting temperature threshold was established for winter wheat, which decreases from south to north but increases from low to high elevation. A spatially explicit temperature model as a function of latitude, longitude and elevation was established to predict planting initiation, while a soil texture-based soil wetness index predicts planting delays due to excessive precipitation. The model was calibrated with 2005–2009 data and validated with 2010–2015 data; it provided sound goodness of fit for planting initiation and weekly planting progression. The spatially explicit model for planting initiation and progression could be used to guide crop production planning and to improve the planting date and progression algorithms in crop models for regional simulation analysis.     

Analysis of Wheat Cultivar Differences in Grain Yield, Grain Nitrogen Yield and Nitrogen Utilization Efficiency.

More detailed information on the causes of yield variability among wheat cultivars is needed to further increase wheat yield. Field studies were conducted in Northern Greece over the two cropping seasons of 1985—1986 and 1986—1987 to assess the effects of nitrogen fertilizer and application timing of the various component traits that determine grain yield, grain nitrogen yield and nitrogen utilization efficiency of two bread ( Triticum aestivum L.) and two durum ( Triticum durum Desf.) wheat cultivars, using yield and yield component analysis. Nitrogen at a rate of 150 kg ha^-1 was applied before planting or 100 N kg ha^-1 before planting and then 50 N kg ha^-1 top dressed at early boot stage. Nitrogen and cultivars affected all traits examined, while split nitrogen application affected only some of the traits. Grain yields in the most cases were correlated with number of grains per unit area and grain weight and grain nitrogen yields in all cases with grain number per unit area. The contribution of the number of grains per spike to total variation in grain yield among cultivars was almost consistent (37 to 55 %), while the contribution of grain weight was more significant (up to 55 %) in high yields (>6.500kg ha^-1) and number of spikes per unit area (>500). The number of grains per spike contributed from 60 to 83 % to the total variation in grain nitrogen per spike. Increased grain nitrogen concentration resulted in a reduction of its contribution in grain nitrogen yield variation. Nitrogen utilization efficiency was higher during grain filling than during vegetative biomass accumulation. The contribution of nitrogen harvest index to the variation of utilization efficiency for grain yield was higher in plants receiving nitrogen application.     

Productivity and Sustainability of Cotton (Gossypium hirsutum L.)–Wheat (Triticum aestivum L.) Cropping System as Influenced by Prilled Urea, Farmyard Manure and Azotobacter

Field experiments were conducted at Indian Agricultural Research Institute, New Delhi, during 2001–2002 and 2002–2003, to study the effect of inorganic, organic and Azotobacter combined sources of N on cotton (Gossypium hirsutum L.) and their residual effect on succeeding wheat (Triticum aestivum L.) crop. The results indicated considerable increase in yield attributes and mean seed cotton yield (2.33 Mg ha^?1) with the combined application of 30 kg N and farmyard manure (FYM) at 12 Mg ha^?1 along with Azotobacter (M₄). The treatment in cotton that included FYM, especially when fertilizer N was also applied could either improve or maintain the soil fertility status in terms of available N, P and K. Distinct increase in yield attributes and grain yield of wheat was observed with the residual effect of integrated application of 30 kg N ha^?1 + FYM at 12 Mg ha^?1 + Azotobacter. Direct application of 120 kg N ha^?1 resulted 67.4 and 17.7 % increase in mean grain yield of wheat over no N and 60 kg N ha^?1, respectively. Integrated application of organic and inorganic fertilizer is therefore, recommended for higher productivity and sustainability of the cotton–wheat system.     

中国东南地区水稻和油菜化肥施用的产量和效益分析

根据国际植物营养研究所东南地区合作研究项目近10年来（2001—2010年）的田间试验、示范、调查和中国农业年鉴的统计数据对该地区水稻和油菜2种主要农作物的产量及产品价格变化情况、商品肥料价格变化情况、水稻和油菜种植的纯收益变化情况进行了分析。分析结果表明,10年间水稻和油菜产量上升了9.2%~31%,产品价格上升了80%~90.9%,同时商品NPK肥料价格上升了48.1%~236.8%,纯收益上升了42%~412.3%。在此基础上对将来肥料和产品价格的变化进行了估算和预测,结果表明产品价格对水稻和油菜种植经济效益的影响最显著,与之相比,肥料价格变化的影响要小得多。因此,建议在肥料使用中更要关注如何进行合理配方,科学施用,提高施肥效益,不必过于在乎肥料价格的高低。     

稻秸还田与播种方式影响小麦出苗及产量的大田试验研究

为了研究水稻秸秆还田与播种方式对小麦出苗及籽粒产量的影响,通过田间大区试验,分析了稻秸机械全量还田与不同播种方式对小麦出苗率、出苗均匀性及产量性状的影响。结果显示,稻秸不还田条件下,机械条播的出苗率显著低于机械匀播和人工撒播,机械条播、机械匀播和人工撒播的出苗率分别为51.84%、90.89%和88.87%;人工撒播的出苗均匀性差于机械条播和机械匀播,3 种播种方式的出苗变异系数分别为0.49、0.26 和0.23。稻秸机械全量还田条件下,不同播种方式处理的出苗率和出苗均匀性都有所降低,其中机械条播的下降幅度较大,出苗率降低了36.54%。小麦出苗率和出苗均匀性通过影响穗数、穗粒数、千粒重而影响籽粒产量,无论稻秸是否还田,机械匀播的产量均高于其余两种播种方式,稻秸不还田和全量还田条件下的产量分别为6091.34 kg/hm2和6476.20 kg/hm2。因此,在稻秸还田小麦生产中,推荐采用机械匀播的播种方式,不仅能提高小麦的田间出苗率,而且能保持较好的出苗均匀性,有利于获得较高的籽粒产量。     

河北省旱地立体农业种植模式研究

研究在调查河北省现有的立体种植模式下,按照不同地区、不同作物类型,将其分为粮粮、粮果、粮油等八大类型,并分析比较得出具有较高经济效益的32种立体农业种植模式。该研究详细介绍了安国市粮药组合、赵县粮油组合、固安县棉粮油组合模式,并具体分析了各种作物的投入、产值及净收益,得出小麦瓜篓比小麦玉米增效55.7%￣64.7%,玉米大豆间作比玉米单作增效46.28%,棉花地芸豆红小豆间作比小麦玉米增效61.4%。对不同种植模式进行产值分析得出,粮果>粮瓜>粮药>粮菜>粮棉>粮油>粮粮。     

施氮量对垄作小麦氮肥利用率和土壤硝态氮含量的影响

以平作为对照,研究了垄作种植方式下施氮量对冬小麦氮肥吸收利用、0~100 cm土层土壤硝态氮含量以及产量的影响。在一定范围内增加施氮量,小麦的氮肥利用率降低,土壤氮的贡献率降低,小麦植株内的氮素积累量增加,收获指数提高,产量增加。低氮(0~66 kg hm^-2)条件下,小麦生育期间土壤硝态氮淋洗损失的可能小,小麦收获后0~100 cm土体内不会累积大量硝态氮。施氮量在165~264 kg hm^-2时,60~100 cm土体内土壤硝态氮含量增加,出现硝态氮下移趋势。种植方式影响小麦的氮肥利用效率,垄作种植小麦氮肥利用率和产量均高于平作小麦。垄作种植麦田60~80 cm土体内土壤硝态氮含量相对较高,而平作种植麦田80~100 cm土层硝态氮含量相对较高。种植方式对氮肥利用率的影响大于施氮量的影响, 但施氮量对氮素收获指数、籽粒产量以及经济系数的影响大于种植方式的影响。本试验条件下,2种种植方式在施氮量为纯氮165 kg hm^-2时可以获得较高的氮肥利用率和氮素收获指数,平作小麦氮肥利用率为35.75%~36.41%,而垄作小麦为45.32%~47.25%; 但2种种植方式的小麦都是施氮量为纯氮264 kg hm^-2时获得最高产量, 平作和垄作小麦的最高产量分别达8 078.31 kg hm^-2和
8 212.27 kg hm^-2。     

抚仙湖北部农田区不同施肥对水稻产量、氮素吸收及利用率的影响

针对抚仙湖北部农田区的蔬菜施肥过量导致土壤养分残余量大,会对后作水稻施肥造成影响的问题,采用田间小区开展不同施肥试验研究。结果表明,砂壤土和粘壤土在施氮量为150~360 kg/hm²范围内,水稻植株氮素积累量随着施氮量的增加而提高,而增加的氮素积累量主要表现在茎叶部位;穗肥施用氮肥可提高籽粒氮素积累量。水稻氮肥吸收利用率和产量,砂壤土以施氮255 kg/hm2时最高,分别为45.1%和10594 kg/hm²;而粘壤土施氮150~360 kg/hm²之间,氮肥吸收利用率为20.9%~22.4%之间,产量为10486~10596 kg/hm2之间;当对砂壤土和粘壤土的水稻穗肥施用氮肥时,水稻氮肥吸收利用率（分别为42.8%、23.5%）和产量（分别为10445 kg/hm²、10564 kg/hm²）最高。水稻的氮素收获指数、氮肥农学利用率、氮肥生理利用率及氮肥偏生产力,均以砂壤土明显高于粘壤土,且随着施氮量的增加而显著下降。蔬菜后作水稻施氮量以150~255 kg/hm²范围为宜,氮肥分基肥50%+分蘖肥30%+穗肥20%施用