基于DSSAT模型的氮肥管理下华北地区冬小麦产量差的模拟

为了评价氮肥管理对华北地区冬小麦产量差的影响,利用大田试验数据和田间调查的方法,应用DSSAT模型分析了吴桥不同氮肥水平下冬小麦多年平均可获得产量及产量差,并研究了不同地块产量差和氮肥农学效率差的分布。结果表明,不同地块冬小麦产量差异显著,但产量变异较小,地块间施肥水平存在明显差异,且变异较大。模型分析确定222 kg/hm2为最佳施氮肥量,对应的最大可获得产量为7618 kg/hm2,地块产量与最大可获得产量有较大差距,当地冬小麦产量具有一定的提升空间。75%的农户地块的施氮量高于最佳施氮量,且氮肥农学效率普遍偏低。因此,生产中应优化氮肥管理方案,适当减氮并调整施肥时期和改进技术,提高氮肥农学效率,以实现冬小麦生产高产高效。在保障国家粮食安全和保护自然环境双重压力的背景下,通过合理的氮肥管理来缩减冬小麦产量差对提高中国粮食总产及保持农业可持续发展具有重要的意义。     

Optimizing nitrogen management strategy under wheat straw incorporation for higher rice production and nitrogen use efficiency

Nitrogen (N) application plays an important role in rice production. Limited attention has already been paid to optimizing N fertilizer management strategy for higher grain yield and nitrogen use efficiency (NUE) of rice with crop residue incorporation. Field experiments were conducted with the objective to determine the response of several N application methods to rice production and to evaluate their NUE. Three N fertilizer application methods, i.e., local farmers' N fertilizer practice (FNP), modified farmers' N fertilizer practice (MNP), and increased the amount of N fertilizer practice (INP), were adopted with zero N application as control (CK). The results showed that, compared with that under FNP, grain yield was significantly higher under MFP, owing to signficantly enhanced total spikelets as a result of more panicles per unit area. Relative to FNP, MNP markedly increased nitrogen agronomic efficiency (AE_N), nitrogen recovery efficiency (RE_N), nitrogen physiological efficiency (PE_N) and nitrogen partial factor productivity (PFP_N), but AE_N, PE_N and PFP_N of INP were significantly lower. Further analysis showed that the number of tiller, leaf area index, aboveground biomass, SPAD value, plant N content and N uptake at the early vegetative stage were improved significantly under MNP compared to those under FNP, contributing to higher total aboveground biomass and total N uptake.     

On-farm trials of site-specific N management for maximum winter oilseed rape (Brassica napus L.) yield

Site-specific nitrogen (N) fertilizer strategy based on soil mineral N (N_min) test is crucial for maintaining high crop yield and high N-use efficiency. A two-year field experiment was conducted to develop a site-specific N fertilizer management for winter oilseed rape in the 2011–12 and 2012–13 seasons in Wuhan, central China. In contrast to fixed N fertilizer recommendation (FN), the use of the N_min test could optimize the N fertilizer inputs in time to fulfill crop N uptake during different growth stages and achieve high seed yield. Despite annual variations in seed yields and N fertilizer recommendations, the N recovery efficiency of the site-specific N fertilizer (SN) treatment was higher than that of the FN treatment. Consequently, the soil-based N strategy matches crop N uptake and soil N supply and achieves high yield depending on the site-specific soil-crop conditions.     

Soil nitrogen balance and nitrogen utilization of winter wheat affected by straw management and nitrogen application in the Yangtze river basin of China

Straw incorporation is a useful management practice in sustainable agricultural systems to improve soil fertility and to reduce air pollution from straw burning. A three-year field experiment was conducted under two rice straw managements and four nitrogen (N) application rates in Rugao, China during 2010–2013, to examine whether straw management practices integrated with fertilizer N applications affect crop yield, N balance and N use efficiency in the wheat season of rice-wheat cropping systems. The results showed that straw incorporation had positive effects on plant N uptake and grain yield. This may be attributed to the greater soil water content and lower amount of seasonal rainfall. However, straw incorporation resulted in lower soil inorganic N and more N surplus at the early growth stage. Grain yield had a significant relation with wheat N uptake from sowing to jointing and from jointing to anthesis with straw incorporation. Therefore, our results suggest that in adjusting the ratio of basal and topdressing N fertilizer, it is important for the supply of optimum N to the crop and to maintain grain production with straw incorporation.     

Nitrous oxide emissions from vegetables grown in a polytunnel treated with high rates of applied nitrogen fertilizers in Southern China

Soils under intensive agricultural practices such as those for growing vegetables in plastic greenhouses are an important anthropogenic source of nitrous oxide (N₂O). Nitrous oxide emissions and measures to mitigate them through fertilizer N management have been less frequently studied than open field systems. The objectives of this study were to measure N₂O emissions from vegetables under greenhouse conditions in Southern China and to investigate the effect of reducing the amount of applied synthetic N fertilizer compared with local practice. Results indicate that the average N₂O‐N flux during the growth of four vegetables (tomato, cucumber, celery and a second tomato crop) was 117.4 ± 9 μg N/m²/h, and the annual emission rate was 8.1 ± 0.6 kg/N/ha for local farms. Temperature was important with much lower emissions during the celery‐growing season when soil and air temperatures were frequently <10 °C. Nitrous oxide emissions from the greenhouse vegetables were seven times greater than from the rice–wheat system in the same area and soils. Reducing the amount of applied synthetic N fertilizer by 40% relative to local farmers’ normal usage could reduce annual cumulative N₂O emissions by 33% without any impact on crop yields.     

Discrepancy in Fertilizer Nitrogen Equivalency Estimates of Dry Sewage Sludge Application in Soil

Fertilizer nitrogen (N) equivalency estimates of sewage sludge are essential to assess benefits from its use in agricultural fields and minimize agronomic failure and environmental risks. Using an outdoor pot experiment, where sludge was applied to the upper layer of the soil in pots, this study aimed to estimate the rate of dried sewage sludge application needed to replace a given amount of inorganic fertilizer and to investigate eventual variations of this estimate depending on whether N replacement value referred to grain yield of barley, biomass production, or overall plant N uptake. Equivalencies were obtained from the response curves of these crop characteristics in relation to the rate of sludge application. It was shown that the patterns of carbon (C) and N allocation to grain and straw were different between the inorganic fertilizer and the sewage sludge treatment, presumably due to the timing of mineral N provision. When the same grain yield was obtained at these two treatments, straw yield and grain N content were greater at the sludge fertilized crop. It was concluded that fertilizer N equivalency value of sewage sludge should inevitably refer to a single crop yield component determined by a producer.     

秸秆还田施氮调节碳氮比对土壤无机氮、 酶活性及作物产量的影响

秸秆的质量,特别是C/N是影响秸秆分解速率和养分释放的重要因素。在秸秆还田条件下,如何科学合理地施用氮肥是秸秆利用和优化施肥研究的关键问题。本研究以秸秆还田施入碳氮的C/N为切入点,于2012—2013年通过田间试验(设秸秆不还田不施肥、秸秆还田不施氮、秸秆还田施用无机氮肥调节C/N为10∶1、16∶1和25∶1以及秸秆还田施用有机氮肥调节C/N为25∶1处理),研究秸秆还田不同氮输入对小麦-玉米轮作田土壤无机氮、土壤微生物量氮、酶活性以及作物产量的影响。结果表明:1)在C/N为25∶1下,施用有机氮肥和无机氮肥对土壤无机氮含量无显著影响;在施用无机氮肥的情况下,C/N越低土壤无机氮含量越高。2)秸秆还田施氮提高了土壤微生物量氮含量,但是各秸秆还田施氮处理之间差异不显著;秸秆还田不同施氮处理对脲酶活性无显著影响;秸秆还田施氮提高了FDA水解酶活性,并随C/N降低呈升高趋势,施用无机氮肥的效果强于施用有机氮肥的。3)秸秆还田施用无机氮肥显著提高了小麦和玉米地上部生物量,施用无机氮肥调节C/N为10∶1和16∶1相比于C/N为25∶1提高了小麦和玉米的苗期和成熟期地上部生物量;施用有机氮肥调节C/N为25∶1相比秸秆还田不施氮对地上部生物量无显著影响。秸秆还田施用无机氮肥提高了作物产量,施用无机氮肥调节C/N为16∶1产量最高,而施用有机氮肥调节C/N为25∶1有降低作物产量的趋势。综合以上结果来看,施用无机氮肥调节C/N为16∶1较为合理。     

稳定氮肥用量对夏玉米产量和氮肥利用率的影响

通过大田小区试验,研究了稳定氮肥不同用量对夏玉米产量、养分累积量、氮肥利用效率及经济效益的影响。结果表明,与不施稳定氮肥相比,稳定氮肥施氮量90、150、210 kg·hm-2和270 kg·hm-2分别增产36.7%、62.1%、76.6%和81.9%,地上部氮素总累积量分别增加39.0%、60.3%、79.0%和113.4%,经济效益分别增加36.1%、61.2%、72.7%和77.1%;与农民习惯施用氮肥相比,高量稳定氮肥用量210 kg·hm-2和270 kg·hm-2分别增产7.3%和10.5%,地上部氮素总累积量分别增加3.2%和23.0%,经济效益分别增加9.7%和11.4%。施用稳定氮肥促进夏玉米对氮素的吸收累积,高量210 kg·hm-2和270kg·hm-2处理较习惯施氮提高总吸氮量。施用稳定氮肥各处理氮肥表观利用率和农学效率显著高于农民习惯施氮,偏生产力高于农民习惯施氮,生理效率除270 kg·hm-2处理外,高于农民习惯施氮。稳定氮肥施氮量在210 kg·hm-2时,能较好地协调玉米高产与稳定氮肥合理利用的统一。     

A review of nitrogen translocation and nitrogen-use efficiency

Nitrogen (N) is a primary nutrient for crop growth. In most agricultural areas, crop production relies heavily on the supply of exogenous N fertilizers. Globally, a large amount of nitrogenous fertilizer is applied to achieve maximum crop productivity. However, N fertilizer application is costly and negatively impacts the environment. One way around these problems is to provide a new N-use efficiency (NUE) framework that promotes the efficient acquisition and use of N and high N translocation rates from vegetative organs to reproductive organs under reduced N inputs. This review integrates the current knowledge about the direct and indirect effects of soil properties, crop varieties, soil water status, soil N fertilizers, and soil microbes on N translocation. In addition, we explore strategies that specifically accomplish N translocation via mycorrhizal fungi. Finally, we discuss recent advances in plant physiology, demonstrating that N translocation is an effective target to improve cereal yields and NUE. Although the relationship between crop variety and N translocation is mostly unknown, understanding this relationship is necessary to select and breed crop varieties that exhibit high yields and N translocation efficiency.     

Optimizing Fertilizer Nitrogen for Winter Wheat Production in Yangtze River Region in China

Excessive nitrogen (N) application has been considered as one of the reasons for restricting yield increases in rice-wheat rotation system in the Yangtze River area. From 2007 to 2009, field experiments were conducted to evaluate the effects of optimized N management on grain yield, nitrogen use efficiency (NUE) and N surplus of winter wheat in Jianghan Plain (Hubei province, China). Results indicated that grain yield and crop N uptake of treatments with reducing fertilizer N (N₁₃₅₍₂₎ for the first year and N₁₂₀₍₃₎ for the second season) did not significantly reduce yield compared to farmers’ practice (FP). Under the same amount of N application, three-time splitting improved grain yield and enhanced NUE as compared with two-time splitting. The optimized N treatment of N₁₃₅₍₂₎ and N₁₂₀₍₃₎ was observed with higher NUE parameters, i.e. recovery efficiency (RE_N), agronomic efficiency (AE_N) and partial factor productivity (PFP_N). Positive correlation between SPAD value and leaf N concentration provided the effective tool to evaluate N status during the growth season. The optimized N rate and top dressing frequency could reduce the residual N retained in the 0–20 cm soil layer after harvest, which could reduce the possibility of soil N loss to the environment. This paper provides insights into N management strategy based on farmers’ practices, which could be regarded as a guideline to improve agricultural management for wheat growth season.     

有机无机复混肥优化化肥养分利用的效应与机理研究Ⅰ. 有机物料与尿素复混对玉米产量及肥料养分吸收利用的影响

本研究采用团粒法工艺,利用味精厂制糖形成的糖渣（A）作为有机原料,与尿素复混制成有机无机复混氮肥,运用土柱栽培试验研究等尿素氮投入条件下（设置低、中、高3个施氮水平）不同有机无机比例的有机无机复混氮肥对玉米产量和养分吸收利用的影响。主要结果为, 1）低氮、中氮和高氮水平下,有机无机复混氮肥处理平均玉米子粒产量比单施尿素处理的分别提高12.4%、4.8%和5.4%;低氮、中氮和高氮水平下,有机无机复混氮肥比对应的有机物料处理的增产幅度均大于尿素处理比对应的不施氮肥（CK）处理的增产幅度,有机物料与尿素复混,明显提高了尿素的增产效果。2）有机物料与化学氮肥复混具有优化化学肥料养分利用和提高化肥利用率的效果。低氮、中氮和高氮水平下,有机无机复混氮肥处理玉米植株氮素吸收量比尿素处理的分别提高29.0%、21.6%和18.9%;低氮、中氮和高氮水平下,有机无机复混氮肥处理化肥氮（尿素N）的表观利用率比尿素处理（尿素N）的氮肥表观利用率分别提高了33.5、11.6和13.0个百分点。     

Influence of Long-term Tillage,Straw, and N Fertilizer Management on Crop Yield,N Uptake,and N Balance Sheet in Two Contrasting Soil Types

Field experiments (established in autumn 1979, with monoculture barley from 1980 to 1990 and barley/wheat–canola–triticale–pea rotation from 1991 to 2008) were conducted on two contrasting soil types (Gray Luvisol [Typic Haplocryalf] loam soil at Breton; Black Chernozem [Albic Agricryoll] silty clay loam soil at Ellerslie) in north-central Alberta, Canada, to determine the influence of tillage (zero tillage and conventional tillage), straw management (straw removed [S_Rem] and straw retained [S_Ret]), and N fertilizer rate (0, 50 and 100 kg N ha^?1in S_Ret, and only 0 kg N ha^?1in S_Rem plots) on seed yield, straw yield, total N uptake in seed + straw (1991–2008), and N balance sheet (1980–2008). The N fertilizer urea was midrow-banded under both tillage systems in the 1991 to 2008 period. There was a considerable increase in seed yield, straw yield, and total N uptake in seed + straw with increasing N rate up to 100 kg N ha^?1 under both tillage systems. On the average, conventional tillage produced greater seed yield (by 279 kg ha^?1), straw yield (by 252 kg ha^?1), and total N uptake in seed + straw (by 6.0 kg N ha^?1) than zero tillage, but the differences were greater at Breton than Ellerslie. Compared to straw removal treatment, seed yield, straw yield, and total N uptake in seed + straw tended to be greater with straw retained at the zero-N rate used in the study. The amounts of applied N unaccounted for over the 1980 to 2008 period ranged from 1114 to 1846 kg N ha^?1 at Breton and 845 to 1665 kg N ha^?1 at Ellerslie, suggesting a great potential for N loss from the soil-plant system through denitrification, and N immobilization from the soil mineral N pool. In conclusion, crop yield and N uptake were lower under zero tillage than conventional, and long-term retention of straw suggests some gradual improvement in soil productivity.     

保障我国粮食安全的肥料问题

肥料在保障我国粮食安全中起着不可替代的支撑作用,同时化肥养分利用率低又产生了对环境的不良影响。因此用好肥料资源、提高肥料利用效率是关系到国家粮食安全和环境质量的重大科技问题。本文实事求是地分析了我国人多、地少、耕地质量差、农田生态环境脆弱的基本国情和肥料领域面临的严重挑战;对国家种植业发展对肥料的需求,有机养分和化肥利用现状和问题、农田中化学氮肥的损失及其对环境的影响等问题进行了较为全面地综述;提出了区域用量控制与田块微调相结合的推荐施肥的理念和技术路线;形成和发展了适合分散经营和规模经营的分区养分管理和精准施肥技术体系;同时对新型肥料和有机养分资源在我国研究应用的现状和存在的问题进行了分析评述。在此基础上,提出了提高耕地综合生产能力、依靠科技进步高效利用肥料资源、按照增产潜力做好施肥区域布局等技术政策,建议针对肥料科学技术的发展形成稳定的政策支持和保障。     

N2O fluxes from a Haplic Luvisol under intensive production of lettuce and cauliflower as affected by different N‐fertilization strategies

Vegetable‐production systems often show high soil mineral‐N contents and, thus, are potential sources for the release of the climate‐relevant trace gas N₂O from soils. Despite numerous investigations on N₂O fluxes, information on the impact of vegetable‐production systems on N₂O emissions in regions with winter frost is still rare. This present study aimed at measuring the annual N₂O emissions and the total yield of a lettuce–cauliflower rotation at different fertilization rates on a Haplic Luvisol in a region exposed to winter frost (S Germany). We measured N₂O emissions from plots fertilized with 0, 319, 401, and 528 kg N ha^–1 (where the latter three amounts represented a strongly reduced N‐fertilization strategy, a target value system [TVS] in Germany, and the N amount fertilized under good agricultural practices). The N₂O release from the treatments was 2.3, 5.7, 8.8, and 10.6 kg N₂O‐N ha^–1 y^–1, respectively. The corresponding emission factors calculated on the basis of the total N input ranged between 1.3% and 1.6%. Winter emission accounted for 45% of the annual emissions, and a major part occurred after the incorporation of cauliflower residues. The annual N₂O emission was positively correlated with the nitrate content of the top soil (0–25 cm) and with the N surpluses of the N balance. Reducing the amount of N fertilizer applied significantly reduced N₂O fluxes. Since there was no significant effect on yields if fertilization was reduced from 528 kg N ha^–1 according to “good agricultural practice” to 401 kg N ha^–1 determined by the TVS, we recommend this optimized fertilization strategy.     

Mitigating nitrous oxide emissions from a maize-cropping black soil in northeast China by a combination of reducing chemical N fertilizer application and applying manure in autumn

Abstract

Nitrous oxide (N₂O) emissions from agricultural soils, mainly caused by chemical nitrogen (N) fertilizer inputs, are major sources of N₂O in Chinese terrestrial ecosystems. Thus, attempts to reduce N₂O emissions from agricultural soils by optimizing N applications are receiving increasing attention. Further, organic fertilizers are being increasingly used in China to improve crop production/quality and prevent or reduce soil degradation. However, organic and chemical fertilizers are often both applied in spring in northeast China, which promotes N₂O emissions and may be sub-optimal. Therefore, we hypothesized that reducing applications of chemical fertilizer N and applying manure in autumn could be an effective strategy for mitigating N₂O emissions from cropped soils in the region. To test this hypothesis, we established a field trial to investigate the effects of different combinations of chemical N fertilizer applications and animal manure in autumn on both N₂O emissions and maize (Zea mays L.) grain yields in northeast China. The treatments, expressed as NxMy (where Nx and My denote the total amounts of chemical fertilizer nitrogen (N) and manure (M) applied in kg N ha^?1 and m³ M ha^?1, respectively), were N₀M₀, N₂₃₀M₀, N₂₇₀M₁₂, N₂₃₀M₁₅, N₃₂₀M₁₈ in 2010 and N₀M₀, N₂₃₀M₀, N₂₀₀M₁₂, N₂₀₀M₁₅, N₂₈₀M₁₈ in 2011. Measurements of the resulting N₂O emissions showed that pulse fluxes occurred after each chemical N fertilizer application, but not after manure inputs in autumn or during soil-thawing periods in the following spring. Emission factors for the chemical fertilizer N were on average 1.07% (1.00?1.10%) and 1.14% (0.49?1.83%) in 2010 and 2011, respectively. Furthermore, by comparing the nine pairs of fertilization treatments, the relative increase in cumulative nitrous oxide-nitrogen (N₂O-N) emissions was found to be proportional to the relative increase in urea application, but independent of the amount of autumn-applied manure. These findings imply that N₂O emissions from fertilized agricultural soils in northeast China could be mitigated by supplying manure in the autumn and reducing the total amount of chemical N fertilizer applied in the following year. Although no significant difference in maize grain yield was found among the fertilization treatments, the grain yield-scaled N₂O emissions for the treatments with a lower chemical N application (e.g., N₂₃₀M₁₅ and N₂₀₀M₁₅ treatments) were significantly lower than those with a higher chemical N application (e.g., N₃₂₀M₁₈ and N₂₈₀M₁₈ treatments). Meanwhile, under the condition of the same application amount of chemical fertilizer N, the grain yield-scaled N₂O emission decreased with the increase of manure application rate. Thus, the results support the hypothesis that combining reductions in chemical N fertilizer and applying manure in autumn could be an effective strategy for mitigating N₂O emissions from N-fertilized soils in northeast China.     

改善根系生长捕获深层土中NO3-N最优化免耕玉米氮肥利用率

Subsoil acidity restricts root growth and reduces crop yields in many parts of the world. More than half of the fertilizer nitrogen(N) applied in crop production is currently lost to the environment. This study aimed to investigate the effect of gypsum application on the efficiency of N fertilizer in no-till corn(Zea mays L.) production in southern Brazil. A field experiment examined the effects of surface-applied gypsum(0, 5, 10, and 15 Mg ha~(-1)) and top-dressed ammonium nitrate(NH_4NO_3)(60, 120, and 180 kg N ha~(-1)) on corn root length, N uptake, and grain yield. A greenhouse experiment was conducted using undisturbed soil columns collected from the field experiment site to evaluate NO_3-N leaching, N uptake, and root length with surface-applied gypsum(0 and 10 Mg ha~(-1)) and top-dressed NH_4NO_3(0 and 180 kg N ha~(-1)). Amelioration of subsoil acidity due to gypsum application increased corn root growth,N uptake, grain yield, and N use efficiency. Applying gypsum to the soil surface increased corn grain yield by 19%–38% and partial factor productivity of N(PFPN) by 27%–38%, depending on the N application rate. Results of the undisturbed soil column greenhouse experiment showed that improvement of N use efficiency by gypsum application was due to the higher N uptake from NO_3-N in the subsoil as a result of increased corn root length. Our results suggest that ameliorating subsoil acidity with gypsum in a no-till corn system could increase N use efficiency, improve grain yield, and reduce environmental risks due to NO_3-N leaching.     

Effect of the Application of Biochar on Selected Soil Chemical Properties,Corn Grain,and Biomass Yields in Iowa

Biochar is a co-product of pyrolysis. To find the effects of biochar on crop production, a field study was conducted in 2007, 2008, and 2009. Treatments were arranged in a split-plot design. The main plot treatments were biochar at rates of 0, 4.5, 18 Mg ha^?1. Sub-plot treatments were nitrogen (N) rates of 0, 56, 112, 224 kg N ha^?1 as urea (46–0–0). These treatments were applied to a continuous corn cropping system. Soil samples were planned to be taken during the first eight weeks of the growing season and after harvest to measure ammonium–N (NH₄ ⁺–N) and nitrate–N (NO₃ ^?–N). Nitrogen in the plant and grain was measured along with grain yield and plant biomass. There was no difference in the yield due to the addition of biochar or the interaction of biochar and N fertilizer, but there were differences due to the N fertilizer alone.     

NITROGEN HARVEST INDEX AND ITS ASSOCIATION WITH CROP YIELDS

Nitrogen (N) is one of the most yield-limiting nutrients in crop production around the world. The main reasons of N deficiency are low recovery efficiency (RE) of applied N fertilizers. The RE efficiency of N by most crop plants is lower than 50%. The lower RE of this element is associated with losses by volatilization, leaching, denitrification, and soil erosion. Some part of N is also immobilized in undecomposed organic materials and by soil microbial population. Nitrogen harvest index (NHI) is a ratio between N accumulated in grain to N accumulated in grain plus straw. The NHI is an important index in determining crop yields because it is positively associated with grain yield. Relationship between GHI and crop grain yield may be positive linear or quadratic depending on crop genotypes and soil and crop management practices adopted. In cereals retranslocation of previously assimilated N in the vegetative parts is the predominant source of N for the grain. The most important practices that can improve NHI are liming acid soils, use of adequate N rates, source and timing, planting N efficient crop species or genotypes within species, and use of appropriate crop rotation.     

水肥耦合条件下作物产量、水分利用和根系吸氮的试验研究

根据1998～2000年两年在北京市水科所永乐店节水灌溉中心开展的冬小麦、夏玉米水肥耦合的田间试验成果的分析研究表明，氮肥效益的发挥与农田水分状况密切相关，低供水水平时(本研究中为冬小麦仅灌拔节水的节水灌溉处理)，肥料的增产效益十分显著，但氮肥贡献率随施肥量的增加而呈递减的趋势。不同的分析方法都表明，在永乐店节水灌溉中心，冬小麦施尿素400 kg/hm²和200 kg/hm²两个施肥水平的试验处理所获得的水(肥)分生产率最高(在不同农田供水状况下)，由于两者的水分生产率差异不大，为提高施肥效率，建议在生产上考虑选择200 kg/hm²的施肥方案较合理。     

吉林省不同生态区玉米施氮效果与氮肥利用效率差异

整理2005—2013年吉林省"3414"田间试验,选取不施氮和推荐施氮处理数据,研究不同生态区玉米的氮肥施用效果和肥料利用效率现状,探讨区域差异及其影响因素。结果显示,吉林省不同生态区的玉米产量水平差异显著,总体上以中部半湿润平原区最高,其次是东部湿润山区,西部半干旱平原区相对较低。不同生态区玉米施氮效果也存在差异,其中东部最高,施氮的平均增产量与增产率分别为2.44 t hm-2和38.4%,其次为中部(2.40 t hm-2,34.3%),西部则显著偏低(2.21 t hm-2,33.4%)。相比中、西部地区,东部地区玉米的氮肥利用效率显著较高,其平均氮肥农学利用率、偏生产力和肥料贡献率分别为16.6 kg kg-1、65.9 kg kg-1和25.0%。随不施氮处理产量的提高,各生态区施氮处理产量均呈上升趋势而氮肥贡献率呈下降趋势,其中,西部地区的相对变幅较中、东部地区更为明显。可见,应根据区域气候环境条件和施氮响应特征对氮肥进行合理的配置与施用,建议吉林中部地区以维持作物需求为标准适当减少施氮量,东部地区可适度增加施氮量并配合栽培措施以消减光温资源不足对产量的限制,而西部地区应在培肥地力基础上推广高效节水用水技术,发挥水氮耦合效应以促进高产高效。