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1.
Appropriate nitrogen (N) management practices are of critical importance in improving N use efficiency (NUE), maize (Zea mays) yield and environmental quality. A six-year (2005–2010) on-farm trial was conducted in Ottawa, Canada to assess the effects of N rates and application methods on grain yield and NUE. In four out of the six-year study, grain yield increased by 60–77 kg ha?1 by sidedress, compared to 49–66 kg ha?1 for each kg N ha?1 applied at preplant. Grain yield response to N between the two strategies was similar in the other growing seasons. Sidedress strategy required 15 kg N ha?1 less of the maximum economic rate of N (MERN) than preplant application. Our results indicate that sidedress application of 90–120 kg N ha?1 with a starter of 30 kg N ha?1 resulted in greater yield, grain quality and NUE than preplant N application in this cool, humid and short growing-season region.  相似文献   

2.
ABSTRACT

This study was conducted to formulate an in-season nitrogen (N) fertilization optimization algorithm (NFOA) to estimate midseason N rates that maximize corn (Zea mays L.) growth and minimize fertilizer inputs. Treatments included: a zero kg N ha?1; three treatments of 134 kg N ha?1 fixed rate applied in split, preplant, or sidedress; two treatments of 67 kg N ha?1 fixed rate preplant or sidedress applied; three NFOA-based midseason N rates (RI-NFOA, RICV-NFOA, flat-RICV-NFOA) with (67 kg N ha?1) and without preplant N; and two resolutions (0.34 and 2.32 m2) tested for RICV-NFOA only. With the 67 kg N ha?1 preplant application, midseason RI-NFOA-based N rates resulted in an N use efficiency (NUE) of 65% while the 134 kg N ha?1 fixed rate split applied had 56% NUE. Using the RICV-NFOA, NUE and net returns to N fertilizer were higher when spatial variability was treated at 2.32 m2 resolution.  相似文献   

3.
With the demand for maize increasing, production has spread into more water limited regions. Couple this with increasing resource costs and environmental concerns and the need for efficient nutrient and water management practices has increased. The objective of this trial was to evaluate the effects of different nitrogen (N) fertilizer application methods and timings on maize grain yield, N use efficiency (NUE), and water use efficiency (WUE) under irrigated and rain-fed conditions. Four site-years of data were collected. Fertilizer treatments consisted of all N applied preplant, split surface applied, and split foliarly applied. Irrigation applied prior to and during reproductive growth increased grain yield, NUE, and WUE compared to rain-fed treatments for all site-years. Split surface applied N fertilizer applications typically increased NUE, but not always grain yield compared to preplant applications. The use of split foliar N fertilizer applications was only beneficial in the site-years when leaf burn was not as severe.  相似文献   

4.
Field experiments were conducted at 15 site-years with barley and 10 site-years with oat over five years to determine the relative nitrogen (N) fertilizer requirements of forage versus grain for barley and oat on Black Chernozem (Typic Agricryoll – 6 site-years on barley and 3 site-years on oat) and Gray Luvisol (Typic Haplocryalf – 9 site-years on barley and 7 site-years on oat) soils in central and north-central Alberta, Canada. Barley harvested for forage responded to higher level of applied N than when it was harvested for grain at most site-years. On average for barley, the amount of N fertilizer required to achieve maximum yield of forage was 58 kg N ha?1 greater than that of grain, and also was somewhat greater on Black Chernozem soils than on Gray Luvisol soils. The results for oat were inconclusive, with almost equal numbers of site-years showed higher N requirements for grain as for forage.  相似文献   

5.
Crop yields are affected by the rate and method of nitrogen (N) fertilizer application. This study was conducted to determine the effects of applying variable N rates by row on maize grain yields. The effects of variable rates and row application were investigated at the R.L. Westerman Irrigation Research Facility near Stillwater, Oklahoma on a Port-Oscar silt loam (fine-silty, mixed, super active, thermic Cumulic Haplustolls) and at Hennessey, Oklahoma on a Bethany silt loam (fine, mixed, thermic Pachic Paleustolls). For 2005 that was characterized by high yields, significant yield differences occurred in non-fertilized rows adjacent to N (67, 100, 134 kg N ha?1) fertilized rows, but not when adjacent to low N [34 and 67 (some cases) kg N ha?1]. In 2006, which had a dry growing season, grain yields were significantly lower than those produced in 2005. With few exceptions, rows receiving N did not produce significantly higher yields in 2006. In 2007, trends were similar to those observed in 2005. Excluding 2006, all site-years showed a significant reduction in yield when N fertilizer was not applied to each row. In order to maximize corn grain yields, N fertilizer should be applied by row, while alternate row N application should be avoided.  相似文献   

6.
The use of optical sensors to detect nitrogen (N) deficiencies and determine in-season fertilizer recommendations has grown. Nitrogen responses are difficult to detect early in the growing season. The objective of this experiment was to determine if different N sources could deliver early season detection of N deficiencies. Four N fertilizer sources were applied at rates of 90 and 180 kg N ha?1 across three site-years. A Greenseeker and SPAD sensor were used to measure in-season fertilizer response index (RI). When differences in sensor RI values between N rates were present, they did not occur until the V9/10 growth stage. No specific N source provided superior results that led to a reliable, early season detection of N deficiency. Reliable differences in response index values could be detected beyond the V7/V8 growth stages. For earlier detection of N responsiveness, and potential N deficiency, other management strategies should be investigated.  相似文献   

7.
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8.
Recent development in canopy optical‐sensing technology provides the opportunity to apply fertilizer variably at the field scale according to spatial variation in plant growth. A field experiment was conducted in Ottawa, Canada, for two consecutive years to determine the effect of fertilizer nitrogen (N) input at variable‐ vs. uniform‐application strategies at the V6–V8 growth stage, on soil mineral N, canopy reflectance, and grain yield of maize (Zea mays L.). The variable N rates were calculated using an algorithm derived from readings of average normalized difference vegetation index (NDVI) of about 0.8 m × 4.6 m, and N fertilizer was then applied to individual patches of the same size of NDVI readings (0.8 m × 4.6 m) within a plot (2184 m2). Canopy reflectance, expressed as NDVI, was monitored with a hand‐held spectrometer, twice weekly before tasseling and once a week thereafter until physiological maturity. Soil mineral N (0–30 cm depth) was analyzed at the V6 and VT growth stages. Our data show that both variable and uniform‐application strategies for N side‐dressings based on canopy‐reflectance mapping data required less amount of N fertilizer (with an average rate of 80 kg N ha–1 as side‐dressing in addition to 30 kg N ha–1 applied at planting), and produced grain yields similar to and higher nitrogen‐use efficiency (NUE) than the preplant fully fertilized (180 kg N ha–1) treatment. No difference was observed in either grain yield or NUE between the variable‐ and uniform‐application strategies. Compared to unfertilized or fully fertilized treatments, the enhancements in grain yield and NUE of the variable‐rate strategy originated from the later N input as side‐dressing rather than the variation in N rates. The variable‐rate strategy resulted in less spatial variations in soil mineral N at the VT growth stage and greater spatial variations in grain yield at harvest than the uniform‐rate strategy. Both variable‐ and uniform‐application strategies reduced spatial variations in soil mineral N at the VT stage and grain yield compared to the unfertilized treatment. The variable‐rate strategy resulted in more sampling points with high soil mineral N than the uniform‐rate strategy at the VT stage.  相似文献   

9.
ABSTRACT

Although spring-applied nitrogen (N) has been shown to be most efficient, the technique of delaying all N applications until mid-season, and the resultant effect on maximum yields, has not been thoroughly evaluated. This experiment was conducted to determine if potential yield reductions from early-season N stress can be corrected using in-season N applications. Data from three experimental sites and two growing seasons (six site-year combinations) were used to evaluate three preplant N rates (0, 45, and 90 kg ha?1) and a range of in-season topdress N rates. Topdress N amounts were determined using a GreenSeeker hand-held sensor and an algorithm developed at Oklahoma State University. Even when early-season N stress was present (0-N preplant), N-applied topdress at Feekes 5 resulted in maximum or near-maximum yields in four of six site-year combinations when compared with other treatments receiving both preplant and topdress N.  相似文献   

10.
AMANULLAH  M. W. KHAN 《土壤圈》2011,21(4):532-538
A field experiment was conducted using a split plot randomized complete block design with three replications to study the effects of potassium (K) and phosphorus (P) application on sunflower (Helianthus annuus L.) growth at the New Developmental Research Farm of Khyber Pakhtunkhwa Agricultural University in Peshawar,Pakistan.Six levels of K (0,25,50,75,100 and 125 kg K ha-1) were main plots while four levels of P (0,45,90 and 135 kg P ha-1) were subplots.Increase in both K and P levels enhanced grain oil concentration of sunflower.Increase in P level increased grain protein concentration,while increase in K level decreased grain protein concentration.Both oil and protein yields increased significantly with increase in K and P levels.The increase in oil and protein yields of sunflower was mainly attributed to the improvement in yield components (grains per head,grain weight and head size) and the significant increase in grain yield.The highest net returns of 297 and 368 US$ ha-1 based on grain and oil yields,respectively,were obtained from a combination of 100 kg K ha-1 + 45 kg P ha-1.  相似文献   

11.
氮施用水平和方式对高粱作物产量和质量的影响   总被引：1，自引：0，他引：1  
A. RASHID  R. U. KHAN  H. ULLAH 《土壤圈》2008,18(2):236-241
A field study was conducted for two years at the Arid Zone Research Institute, Dera Ismail Khan, Pakistan, to determine the optimum level of nitrogen and efficient application method in the production of sorghum （Sorghum bicolor L.）. Using four levels of nitrogen, i.e., 0, 60, 90, and 120 kg ha^-1, and two different application methods （soil application and foliar spray）, the experiment was laid out in a split-plot design, where the main plots were used to determine the effective method of application and the subplots were used to detect the influence of N levels on the grain yield. The average data obtained after two years of study indicated an increase in the grain yields with an increase in N levels irrespective of the method used of N application. The grain yield increased from 2.92 to 5.61 t ha^-1 in the plots that were treated with 90 kg N ha^-1 compared with the control plots. Quadratic regression analysis showed that the increase in the yield was higher at the lower levels of N compared with the succeeding higher levels. The soil application method, producing an average grain yield of 4.79 t ha^-1, was found to be superior to the foliar spray method with an average grain yield of 4.56 t ha^-1. The protein content of the grain showed a linear increase with N application, attaining the maximum at 120 kg N ha^-1 in both the methods of N application. In addition, compared with the method of soil application, higher crude protein contents were observed using the method of foliar spray at all N levels.  相似文献   

12.
Midseason fertilizer nitrogen (N) rates based on predicted yields can be projected if the quantity of N accumulated in winter wheat (Triticum aestivum L.) and corn (Zea mays L.) is known especially early in the growing season. This study was conducted in 2006 and 2007 to establish the amount of N accumulated in corn and winter wheat over the entire growing season. Plots representing three N fertilization rates 0, 45, and 90 kg ha?1 at Stillwater and 0, 67, and 112 kg ha?1 at Lahoma were selected from two long-term wheat experiments located at research stations in Stillwater and Lahoma, Oklahoma. For corn, three N fertilization rates 0, 112 and 224 kg ha?1 at Lake Carl Blackwell and 0, 56 and 112 kg ha?1 at Perkins were selected from N studies, located at research stations near Lake Carl Blackwell and Perkins, Oklahoma. Sequential aboveground biomass samples were collected from 1 m2 area of wheat and 1.5 m long row (0.76 cm spacing) for corn throughout their respective growing seasons. In general, this work showed that more than 45% of the maximum total N accumulated could be found in corn plants by growth stage V8 (8th leaf collar fully unfolded). For winter wheat, more than 61% of the maximum total N accumulated at later stages of growth could be accounted for by Feekes growth stage 5 (F5, leaf strongly erected). Our findings are consistent with those of others showing that yield potential can be predicted at mid-season since such a large percentage of the total N accumulated was accounted for early on in the growing cycle of either wheat or corn.  相似文献   

13.
春玉米连作体系高产栽培模式优化研究   总被引：5，自引：0，他引：5  
【目的】 通过探讨春玉米土壤物理性状、根系动态变化、产量等对不同农学管理模式的响应,为优化玉米高产高效栽培技术提供理论依据。 【方法】 以先玉335为供试品种,进行了三年大田定位试验,对种植密度、肥料施用、土壤耕作三项关键技术进行优化组合。设计了4种模式:1) 按照当地农户习惯,种植密度5.0万株/hm2,一次性施用化肥N 225、P2O5 82.5、K2O 67.5 kg/hm2,灭茬旋耕 (CK);2) 种植增密至6.0万株/hm2,化肥用量为N 195、P2O5 75、K2O 82.5 kg/hm2,氮肥分两次施用,播前和拔节期分别施78和117 kg/hm2,基施有机肥15000 kg/hm2及中微肥60 kg/hm2,灭茬旋耕 (Opt-1);3) 种植密度7.0万株/hm2,施化肥量为N 300、P2O5 120、K2O 120 kg/hm2,氮肥分三次施用,播前、拔节和抽雄期分别施用120、120、60 kg/hm2,磷肥和钾肥分两次施用,播前和拔节分别施用96和24 kg/hm2,基施有机肥15000 kg/hm2及中微肥150 kg/hm2,拔节期深松 (Opt-2);4) 施化肥N225、P2O5 90、K2O 90 kg/hm2,氮肥分三次施用,播前、拔节和抽雄期分别施用90、90、45 kg/hm2,磷肥和钾肥分两次施用,播前和拔节分别施用72和18 kg/hm2,有机肥、中微肥和种植密度同Opt-2(Opt-3)。调查了产量构成、氮素吸收、0—60 cm土壤物理性状和根系动态变化。 【结果】 产量主要是依靠收获穗数的增加来实现,Opt-1、Opt-2、Opt-3处理下的产量分别较CK高12.1%、15.3%和13.9%。与Opt-3处理相比,Opt-2处理氮肥用量增加33.3%,吸氮量仅增加6.9%,且多集中于茎叶,产量未增加。Opt-2、Opt-3处理在拔节期深松后,吐丝期和乳熟期固相比例有所下降,尤以乳熟期较为显著,平均各土层分别降低了8.8%和7.4%,进而增加了0—40 cm耕层土壤的通透性。Opt-1、Opt-2、Opt-3处理在0—10 cm土层根长、根重和根表面积均显著高于CK,在30—40 cm土层Opt-2、Opt-3处理的根长和根表面积比CK分别增加36.6%、44.6%和34.9%、37.1%;与CK相比,Opt-1、Opt-2、Opt-3处理在玉米吐丝期0—60 cm土壤硝态氮残留量分别减少45.7%、31.0%、23.2%,且处理间差异显著。Opt-2和Opt-3处理在12展叶期进行深松追肥后促进了硝态氮的下移。 【结论】 通过增密、调肥、深松三项技术措施的集成优化,提高了0—40 cm耕层土壤的通气性,促进了玉米根系下扎且充分生长,吸收利用了0—60 cm土层中的硝态氮,进而显著增加了产量和肥料利用率。通过调整施肥量,补充有机肥和中微量元素,氮磷钾肥分两次施用并结合拔节期深松,其产量和吸氮量较目前常规栽培模式增幅分别为13.9%和9.5%,是较优的栽培技术模式。   相似文献   

14.
氮肥用量对太湖水稻田间氨挥发和氮素利用率的影响   总被引：28，自引：0，他引：28  
Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 （control）, 100, 200, 300, or 350 kg N ha^-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates （300 and 350 kg N ha^-1） showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha^-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.  相似文献   

15.
Methods for determining midseason nitrogen (N) rates in corn have used the parameter normalized difference vegetation index (NDVI) and, in some cases, plant height. The objective of this study was to analyze the relationship of stalk diameter along with predictors of yield, including NDVI and plant height with grain yield. Five site-years of data were analyzed, where several rows of corn plants were selected, and yield from plants within the row was recorded individually. Measurements of stalk diameter, plant height, and NDVI were taken from growth stages V8–VT. Using a value of stalk diameter × plant height gave the best correlation with grain yield (r2 = 0.34, 0.55, 0.67; V8, V10, V12, growth stages respectively). This work showed that stalk diameter × plant height was positively correlated with by-plant corn grain yields, and this parameter could be used for refining midseason fertilizer N rates for growth stages V8–V12.  相似文献   

16.
本试验利用１５Ｎ示踪技术，研究３种施氮水平（适宜施氮量Ｎ１０∶１５０ｋｇＮ·ｈａ－１，低于适宜施氮量的５０％Ｎ０５∶７５ｋｇＮ·ｈａ－１，高于适宜施氮量的５０％Ｎ１５∶２２５ｋｇＮ·ｈａ－１）对灌溉冬小麦氮素利用、去向及作物产量的影响。结果表明：在灌溉条件下，３种施氮水平（Ｎ０５，Ｎ１０，Ｎ１５）的冬小麦氮素利用效率分别为３８５％、３２３％和２２４％，以Ｎ０５水平为最高。Ｎ１０施氮水平获得了最高的作物产量（６８０×１０３ｋｇ籽粒·ｈａ－１，１４７×１０３ｋｇ生物量·ｈａ－１），Ｎ０５水平同Ｎ１０水平相比，在产量上没有显著性差异；而Ｎ１５水平因施氮过量造成籽粒产量明显下降，与不施肥相比，差异不显著。在深层条施（５～８ｍｍ）条件下，仍有３０２％～３６７％的化学氮素通过各种途径而损失。在Ｎ１５水平中，施用氮素的４６％仍存在于０～５０ｃｍ土层中，远远高于其它两种施肥水平。土壤残留态的无机氮素含量以Ｎ１５施氮水平为最高  相似文献   

17.
The use of in-row subsoilers in conservation tillage systems in soils underlaid by tillage pans increases rooting depth, root proliferation and water infiltration. Interrow subsoiling 5 weeks after planting, to coincide with sidedress nitrogen applications, might be a practical method for further increasing infiltration of water from irrigation and high-intensity showers. Corn (Zea mays L.) was strip-till planted and grown under irrigation for 2 years at one location and 1 year at another to study the effects of subsoiling, placement and timing of nitrogen application (157 kg ha−1) on plant growth, stomatal conductance and yield. Treatments included (1) not subsoiled, N applied at planting; (2) subsoiled in-row at planting, N applied at planting; (3) not subsoiled, N applied 5 weeks after planting; (4) subsoiled in-row at planting, N applied 5 weeks after planting; (5) subsoiled interrow, and N applied 5 weeks after planting; and (6) subsoiled in-row at planting and interrow 5 weeks after planting, N applied 5 weeks after planting. Nitrogen applied 5 weeks after planting resulted in higher yields than when applied at planting. In-row subsoiling at planting, interrow subsoiling 5 weeks after planting and subsoiling in-row at planting plus interrow 5 weeks later resulted in increased stomatal conductance between irrigations. Delaying N application resulted in decreased stomatal conductance in treatments that were in-row subsoiled at planting. Grain yields were lower without than with subsoiling, especially when N was applied at planting. When water was not limiting, subsoiling interrow 5 weeks after planting was as effective in increasing grain yield as in-row subsoiling at planting. In one test, the highest grain yield (9.96 t ha−1) resulted from the cumulative effect of subsoiling in-row at planting plus interrow 5 weeks later.  相似文献   

18.
生长调节剂对玉米氮代谢的影响   总被引：7，自引：1，他引：7  
采用田间小区试验,研究了植物生长调节剂不同配方对玉米光合特性、氮素代谢以及玉米子粒产量与蛋白质含量的影响。结果表明,调节剂不同配方处理能明显提高子粒灌浆期玉米功能叶叶绿素的含量和净光合速率,功能叶与茎秆中的全氮和蛋白氮的减少量,功能叶的硝酸还原酶、谷氨酰胺合成酶与转化酶活性及子粒谷氨酰胺合成酶与转化酶活性;灌浆中、后期玉米功能叶蛋白水解酶活性和玉米子粒产量、子粒蛋白质含量及蛋白质产量。在生长调节剂中,PGR4处理玉米子粒的蛋白氮含量比对照提高1.35.g/kg,子粒产量比对照增加9.5%,子粒蛋白质产量比对照增加19.6%;PGR3处理玉米子粒的蛋白氮含量比对照提高0.78.g/kg,子粒产量比对照增加11.4%,子粒蛋白质产量比对照增加17.4%,是较合理的配方。  相似文献   

19.
太湖地区水稻最适宜施氮量研究   总被引：4，自引：0，他引：4  
To determine the optimal amount of nitrogen(N) fertilizer for achieving a sustainable rice production at the Taihu Lake region of China,two-year on-farm field experiments were performed at four sites using various N application rates.The results showed that 22%-30% of the applied N was recovered in crop and 7%-31% in soils at the rates of 100-350 kg N ha 1.Nitrogen losses increased with N application rates,from 44% of the applied fertilizer N at the rate of 100 kg N ha 1 to 69% of the N applied at 350 kg N ha 1.Ammonia volatilization and apparent denitrification were the main pathways of N losses.The N application rate of 300 kg N ha 1,which is commonly used by local farmers in the study region,was found to lead to a significant reduction in economic and environmental efficiency.Considering the cost for mitigating environmental pollution and the maximum net economic income,an application rate of 100-150 kg N ha 1 would be recommended.This recommended N application rate could greatly reduce N loss from 199 kg N ha 1 occurring at the N application rate of 300 kg N ha 1 to 80-110 kg N ha 1,with the rice grain yield still reaching 7 300-8 300 kg DW ha 1 in the meantime.  相似文献   

20.
ABSTRACT

Nutrient uptake and grain and straw yield of Egyptian winter wheat (Triticum aestivum L. Merr.) were evaluated for two site-years after the seed inoculation with two biofertilizer products, Phosphorien, containing the phosphorus (P)-solubilizing bacteria Bacillus megatherium, and Nitrobien, containing a combination of nitrogen (N)-fixing bacteria Azotobacter chroococcum and Azospirillum liposerum. Ammonium nitrate and polymer-coated urea fertilizers were applied to plots alone and together with the biofertilizers at rates of either 83 kg N ha?1 or 186 kg N ha?1 for comparison. The highest grain yield (5.76–6.74 Mg ha?1) and straw yield (11.49–13.32 Mg ha?1) occurred at the highest fertilizer rates with N fertilizer. There was a slight additional increase in grain and straw yields when a biofertilizer was applied along with N fertilizer. A slightly higher grain and straw yield was measured with the polymer-coated urea treatment than with the ammonium nitrate treatment. The biofertilizer materials were not as effective as N fertilizers in producing grain (4.02–4.09 Mg ha?1) or straw (7.71–8.11 Mg ha?1) for either year, although the Nitrobien + Phosphorien combination increased these parameters over the N-fertilizer control. The effect of the Nitrobien biofertilizer in increasing grain yields was equivalent to a urea application rate of about 13 kg N ha?1. Biofertilizer inoculations increased iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) concentrations in wheat tissue (at boot stage), but these higher levels did not influence grain or straw yield.  相似文献   

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