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1.
The increasing cost of commercial fertilizers and environmental problems associated with improper fertilization management have prompted the need to re‐examine commercial N sources that can effectively supply N to pastures while minimizing N losses. This 3‐year study evaluated the effects of selected N sources on bahiagrass (Paspalum notatum Flügge) responses, soil properties and N losses. Treatments consisted of a factorial combination of 6 N sources [(i) ammonium nitrate (AN), (ii) ammonium sulphate (AS), (iii) urea (U), (iv) urea treated with Agrotain (U + Agrotain), (v) SuperU and (vi) ammonium sulphate nitrate] and 3 N levels (0, 60 or 120 kg ha?1 year?1), replicated three times. Bahiagrass dry‐matter yield (DMY), crude protein (CP) concentration, N uptake and recovery were not affected by N source, with the exception of AN that resulted in reduced DMY in 2010 compared with the other sources. Bahiagrass DMY, CP concentration, N uptake and recovery increased linearly as N levels increased. Nitrogen fertilization showed no effect on soil pH or soil N accumulation. Soil pore‐water N concentrations from treatments fertilized with N were similar to the control plots indicating no threat to the environment. At the N levels evaluated in this study, selection of N source should be based on the fertilizer cost.  相似文献   

2.
通过盆栽试验,研究了同等氮量,不同基肥、追肥比例对小白菜产量、硝酸盐含量以及氮肥利用率的影响。结果表明:小白菜产量以追肥质量比为75%的处理(N4)最高,全部用作基肥的处理(N1)最低,依次为N4>N2>N3>N1;50%氮肥作追肥的处理(N3)硝酸盐含量最高,75%氮肥作追肥的处理(N4)硝酸盐含量最低,依次为N3>N1>N2>N4 ;氮肥利用率随追肥质量比增加而增加,其中N4的利用率比N1 高出9.94%,差异达到显著水平。同等氮量条件下,以N4的基肥、追肥质量比最佳。  相似文献   

3.
氮肥用量对吉林省玉米产量和氮肥利用效率的影响   总被引：2，自引：1，他引：2  
选取2005~2013年吉林省"3414"田间试验中的氮肥用量处理,研究施氮水平对玉米产量和氮肥利用效率的影响,明确不同生态区之间的差异。结果表明,不施氮条件下吉林省玉米的平均产量为7 596 kg/hm~2。氮肥施用显著提高玉米产量,以适宜施氮量(N3)处理表现最好,产量最高达9 967 kg/hm~2,较不施氮(N1)处理平均增产2 371 kg/hm~2。玉米的氮肥农学利用率和偏生产力均以适宜施氮量的1/2(N2)处理最高,随施氮量增加氮肥利用效率均逐渐降低。不同生态区显著影响玉米的增产效果和氮肥利用效率,吉林省中部半湿润平原区的产量水平最高,东部湿润山区次之,西部半干旱平原区最低。施氮增产量和农学利用率以东部地区显著高于中、西部地区,偏生产力以东部地区最高而西部地区最低。  相似文献   

4.
施肥方式对玉米－大豆套作体系氮素吸收利用效率的影响   总被引：7，自引：0，他引：7  
通过田间试验探讨了A1（N,210kg•hm-2）、A2（N,270kg•hm-2）、A3（N,330kg•hm-2）3种施氮水平和距窄行玉米0cm(B1)、15cm(B2)、30cm(B3)、45cm(B4) 4种施肥距离对玉米——大豆套作体系氮素吸收利用效率的影响。结果表明,与习惯施氮（A3）相比,减量施氮（A1、A2）提高了大豆R2、R5期单株根瘤数、根瘤干重和根瘤固氮潜力,以距玉米15cm处施肥的根瘤固氮能力较强;玉米、大豆的籽粒产量、地上部植株氮素吸收量和氮肥利用率随施氮量的增加呈先增加再降低的趋势,以A2处理的最高;施肥距离过大和过小均不利玉米、大豆产量的提高和氮素的吸收利用,以距玉米15~30cm处施肥效果最佳;减量施氮18%（A2）时,B2、B3处理相对常规穴施（B1）处理,玉米、大豆及玉米－大豆系统的籽粒产量、植株氮素吸收量、氮肥利用率和土壤总氮含量均显著提高,土壤氮素贡献率显著降低。  相似文献   

5.
Efficient use of nitrogen fertilizer is critical in improving yield stability in rice. The objective of this study was to determine the effect of nitrogen (N) top-dressing on the number of total spikelet (fertile plus sterile) production and evaluate the effect among rice cultivars. We analyzed 136 sets of experimental data on growth and spikelet production for three lowland cultivars, grown under various regimes of N over 10 seasons at Kyoto, Ibaraki and Kanagawa, Japan. In each season, one to three of the lowland cultivars, Nipponbare (japonica), Koshihikari (japonica) and Takanari (indica), were studied. In 1986, 1995 and 1999-2001, the N regimes included basal application only, light basal and heavy top-dressing from the panicle initiation stage onward, heavy basal and heavy top-dressing from the spikelet formation stage onward, and no applications. In 2002 and 2005-2008, we set up experimental plots with varied time of N top-dressing, with or without N basal application. Takanari had the largest spikelet number averaged over all plots and was considered better efficient in spikelet production per applied N than the other cultivars. Although the trend is not clear, the effect of time of top-dressing on spikelet number was generally the greatest when N was top-dressed from 35 to 30 days before heading. The variation of observed spikelet number was analyzed with a linear regression of plant N 14 days before heading and by a model that estimates spikelet production accounting for plant N 14 days before heading and crop growth rate (CGR) during the 14-day period preceding heading. For the variation of spikelet number within each cultivar, the linear function model expressed the observed spikelet number than the two function model with R2 0.43** versus 0.13*-0.28** for the former and later models, respectively. When the results of all cultivars were combined, the two function model was much better for estimation of spikelet number than the linear function model (R2 = 0.36** vs. 0.20*). This indicates that yearly and varietal variation of spikelet number was caused mainly by plant N status at the late spikelet differentiation stage. The varietal variation in spikelet production efficiency is explained by CGR during this 14-day period. We concluded that N applications that increase plant N 14 days before heading is highly effective in maximizing spikelet production among cultivars.  相似文献   

6.
中性紫色土施氮对小麦氮素吸收利用及产量和品质的影响   总被引：2，自引：1，他引：2  
为给西南地区小麦高产优质栽培中合理施氮提供依据，以西农麦1号为材料，在西南地区有代表性的中性紫色土上，研究了施氮对小麦氮素吸收利用及产量和品质的影响。结果表明。施氮在0～225kg／ha范围内，随氮肥用量的增加，小麦对氮的吸收量、籽粒粗蛋白质含量、籽粒产量和茎叶干重都显著增加，但氮的收获指数和氮肥的农艺效率却呈下降趋势。小麦各处理氮肥利用率平均为39．6％，以施纯氮75kg／ha水平最高。施氮对改善小麦的品质作用明显，其中籽粒淀粉含量以施纯氮量150kg／ha时最高。  相似文献   

7.
不同阶段施用氮肥对大豆氮吸收及固氮的影响   总被引：1，自引：0，他引：1  
以两种不同基因型的大豆品种为试材，研究不同阶段施用氮肥对大豆吸氮及固氮的影响。试验结果表明，氮肥的施用时间对大豆氮吸收、根瘤干重及固氮，具有重要影响。仅施２５ｋｇ／ｈｍ２的启动氮，两个大豆品种都获得了最高的根瘤干重和固氮率。在开花期或种于形成初期，再追施５０ｋｇ／ｈｍ２氮，两个大豆品种都获得了最高的氮吸收总量和固氮总量。大豆的根瘤干重与固氮率呈线型正相关。  相似文献   

8.
为了解麦田杂草氮素吸收对施氮量的反应,在半湿润地区,以土垫旱耕人为土为供试土壤,通过田间小区试验,研究了不同施氮水平下冬小麦田间杂草含氮量及吸氮量的变化以及杂草与小麦氮素的竞争关系.结果表明,小麦不同生育时期麦田杂草含氮量存在差异,表现为越冬期＞返青期＞拔节期＞成熟期;杂草含氮量随施氮量的增加而增加,尤其是在小麦生育前期施氮处理间差异达到显著水平.小麦不同生育期的杂草吸氮量呈现先上升后下降的趋势,在拔节期达到最大,各生育期间差异极显著;在小麦不同生育期,杂草吸氮量对施氮水平的反应不同,与不施肥的对照相比,施肥有利于前期杂草对氮素的吸收,中后期表现为降低的趋势.从相对吸氮量看,增加施氮提高了前期杂草对氮素的竞争能力,而后期杂草的竞争力下降.  相似文献   

9.
Summary

Carbon (C) and nitrogen (N) metabolisms are two major metabolic pathways which have been intensively studied in plants. Both N and C metabolisms are tightly linked in numerous plant biochemical pathways. Therefore the C to N ratio has to be carefully regulated to ensure proper functioning of the huge metabolic network. In order to maintain a viable C/N status under a large range of growth conditions plants have evolved complex mechanisms to regulate the delicate network of these two major assimilatory pathways. C and N metabolisms are both highly regulated. We will present the current knowledge on the regulation of N and C metabolisms by sugars and N metabolites. Players involved in these regulatory processes are just starting to be uncovered and possible signaling molecules involved in these regulations as well as known or potential candidate regulatory genes willbe discussed.  相似文献   

10.
设置大田试验,利用吐丝期自然干旱胁迫研究灌水(自然干旱、灌水30 mm、灌水60 mm,分别为W0、W1和W2)和施氮(0、100、200、300 kg/hm~2,分别为N0、N1、N2、N3)对玉米产量、干物质累积与分配、氮素吸收与利用的影响及其耦合效应,并探讨适宜的水、氮组合调控措施。结果表明,吐丝期自然干旱条件下灌水和施氮均显著影响玉米成熟期的产量、干物质累积量、收获指数、氮素吸收量及氮肥利用效率,且两种措施具有显著的交互作用。W2N3处理的玉米产量最高,达9 666 kg/hm~2。干物质累积量和氮素吸收量随灌水量、施氮量的变化趋势与产量类似,收获指数和氮素利用效率存在明显差异。W0N0和W1N0处理的收获指数相比其他处理显著偏低,说明干旱和缺氮限制干物质向子粒的转运分配。玉米施用氮肥的表观利用率、农学利用率和偏生产力在灌水条件下均显著高于自然干旱条件,随施氮量增加而逐渐降低,均在W2N1处理达最高。  相似文献   

11.
To explain the observation in field experiments that tobacco variety CB-1 was more nitrogen(N)-efficient than K326, the influence of two N levels on growth, N uptake and N flow within plants of the two tobacco varieties was studied. Xylem sap from the upper and lower leaves of both tobacco varieties cultured in quartz sand was collected by application of pressure to the root system. CB-1 took up more N with smaller roots at both high(HN, 10 mmol L-1) and low(LN, 1 mmol L-1) N levels, and built up more new tissues in upper leaves especially at LN level,than K326. Both varieties showed luxury N uptake, and CB-1 accumulated significantly less NO-3in new tissues than K326, when grown at the HN level. At both N levels, the amount of xylem-transported N and phloem-cycled N from shoot to root in K326 was greater than those in CB-1, indicating higher N use efficiency in CB-1 shoots than in K326 shoots. The major nitrogenous compound in the xylem sap was NO-3irrespective of N level and variety. Low N supply did not cause more NO-3reduction in the root. The results indicated that the N-efficient tobacco variety CB-1 was more efficient in both N uptake by smaller roots and N utilization in shoots, especially when grown at the LN level.  相似文献   

12.
以重穗型杂交稻德优4727和轻穗型常规稻五山丝苗为材料,设置4个施氮量(0、120、165、210 kg/hm~2,分别记为N0、N120、N165、N210)和3种移栽密度(25.0、19.1、12.5丛/m~2,分别记为D1、D2、D3),于2016年在四川德阳进行大田试验,研究施氮量和移栽密度对重穗型杂交稻产量及氮肥利用率的影响。结果表明,参试水稻品种的适宜移栽密度均为25.0丛/m~2,在此移栽密度下,重穗型杂交稻德优4727产量随施氮量的增加呈先增加后下降的趋势,以N165处理产量最高(10.90 t/hm~2),轻穗型常规稻五山丝苗产量随施氮量的增加呈升高趋势,以N210处理产量最高(10.21 t/hm~2);相同移栽密度下,参试水稻品种氮肥利用率随施氮量的增加呈下降趋势;随移栽密度的增加,参试水稻品种产量和氮肥利用率呈增加趋势。可见,提高移栽密度,减少施氮量可兼顾水稻高产和氮肥高效利用,其最佳肥密组合为施氮量165 kg/hm~2、移栽密度25丛/m~2,即低氮密植可作为重穗型杂交稻高产高效栽培的关键技术。  相似文献   

13.
《Plant Production Science》2013,16(2):156-167
Abstract

We tested the hypothesis that elevated CO2 concentration [CO2]-induced enhancement of biomass production of soybean is greater in a genotype that has a higher nitrogen (N) fixation capacity. Furthermore, we analyzed theinteractive effects of N fertilization, temperature and [CO2] on biomass production. Three genetically related genotypes: Enrei (normally-nodulating genotype), Kanto 100 (supernodulating genotype), and En1282 (non-nodulating genotype) were grown in pots, with or without N fertilizer for two years (2004, 2005). They were then subjected to two different [CO2] (ambient and elevated (ambient + 200 ?mol mol-1)) × two temperature regimes (low,high (low + 4~5ºC)). Top dry weight at maturity was the greatest in the elevated [CO2] × high temperature regime, irrespective of genotype and N fertilization. The [CO2] elevation generally enhanced N acquisition and dry matter production during the vegetative growth stage, and the enhancement was more pronounced in the nodulating genotypes (Enrei and Kanto 100) than in the non-nodulating genotype (En1282), indicating that N supply through N fixation contributes to elevated [CO2]-induced biomass production in soybean. However, the relative responsiveness ofbiomass production to elevated [CO2] was not necessarily higher in the supernodulating genotype than the normally-nodulating genotype. The N utilization efficiency to produce biomass was inferior in the supernodulating genotype than in the normally-nodulating and non-nodulating genotypes. These results did not fully verify the hypothesis that elevated [CO2]-induced enhancement of biomass production of soybean is greater in a genotype with a higher N fixation capacity.  相似文献   

14.
通过施氮（N）处理试验,研究了甘蓝型杂交油菜宁杂1号苗期不同叶片的N素含量变化,结果表明：（1）不同叶位的叶片含N率随叶位上升而逐渐提高。（2）苗期植株体内的N素总量主要分布于中部3片叶,并集中于叶片,叶柄含N率较低。（3）单位叶面积含N率以倒数第2展开叶最高,衰老叶片只有正常叶片的1／3左右。（4）增施N肥能明显提高各叶位叶片的含N率、N素总量以及单位叶面积含N率,特别对叶片的作用较大。  相似文献   

15.
The typical size structuring process that occurs as a consequence of intra-specific competition in maize promotes the appearance of contrasting plant hierarchies (i.e. dominated and dominant individuals). This process may become more intense under low nitrogen (N) availability. The alleviation of plant competition by N addition may reduce plant yield variability through a differential response to N in individuals of contrasting hierarchies. In this work, the response to N of dominated and dominant plants from stands with contrasting N supply (0 to 140-200 kg N ha−1) was examined on 11 experiments carried out in Paraná, Argentina (31°50′S; 60°31′W) in a broad range of growing conditions that included the variation of the year, genotype, plant population and sowing date. Our objectives were: (i) to evaluate the response to N in contrasting plant hierarchies of maize, (ii) to quantify the contribution of dominated and dominant plants to the response to N of the overall stand, and (iii) to study the effect of N on relationships between plant hierarchies and stand variability. Response to N of yield per plant was associated with biomass per plant in non-fertilized controls, tending to be higher in plants with low biomass. The response to N of yield per unit area (i.e., considering all individuals of the stand) was related to the response to N of dominant and dominated plants (P < 0.0001). However, at a higher level of response to N of grain yield per unit area (>50-60%), dominant plants had a considerable lower response than dominated plants, whereas at a lower level of response (<30%), the contribution of contrasting plant hierarchies was similar. In stands with similar plant biomass between hierarchies, the differences in the response to N between plant types tended to be negligible. The coefficient of variation of yield per plant was reduced (P < 0.05) by effect of N in 4 out of 11 experiments, although it tended to be consistently lower in fertilized treatments. When the differences between the biomass of dominated and dominant plants were ample we found the highest response to N at the stand level, as a result of the higher increase in grain yield per plant in dominated plants than in dominant ones. The response to N in each plant hierarchy was differentially associated with increases in shoot biomass, harvest index, kernel number per plant and kernel weight.  相似文献   

16.
湖北省油菜氮肥效应及推荐用量研究   总被引：17，自引：2，他引：17  
通过15个田间试验研究湖北省油菜主产区氮肥效应和适宜用量。结果表明适量施用氮肥对油菜具有明显的增产增收效果,施氮比不施氮对照增收油菜籽402~2759kg/hm2,平均增产1270kg/hm2,平均增产率达133.0%;施氮纯利润平均为3403元/hm2,产投比平均达6.00;氮肥偏生产力和农学利用率平均分别为17.6kg/kg N和8.0kg/kg N。根据肥料效应方程,在当前生产条件下,油菜生产的氮肥最佳经济用量为120.1~325.4kg N/hm2,平均用量为199.6kg N /hm2。土壤碱解氮含量与油菜氮肥最佳经济推荐用量呈极显著负相关性（r﹦﹣0.7734**,n﹦12）,根据土壤碱解氮含量（x,单位为mg/kg）水平,湖北省目前油菜生产适宜用氮量（y,单位为kg/hm2）可通过公式y﹦553.72﹣74.699Ln（x）求得。  相似文献   

17.
冬小麦同化物、氮素转移量和转移效率对氮肥的反应   总被引：2，自引：3，他引：2  
为探究不同品种冬小麦花前同化物和氮素转移对氮肥的反应,以NR9405、9430、偃师9号、小偃6号、陕229号和西农2208等冬小麦品种为供试材料，通过盆栽试验，测定和分析了土壤不同供氮状况下冬小麦花前同化产物和氮素转移的变化。结果表明，施用氮肥可显著增加冬小麦花前干物质转移量和转移效率以及花前和花后吸氮量、花前氮转移量，提高花前干物质对籽粒的贡献率、总吸氮量和籽粒产量，但降低了花前氮的转移效率、对籽粒的贡献率和氮素利用效率。品种间花前干物质转移量、转移效率、对籽粒的贡献率、籽粒产量以及花前吸氮量、花后吸氮量、总吸氮量、花前氮转移量、转移效率、对籽粒的贡献率、氮素利用效率均存在显著或极显著差异。施氮后不同品种的干物质和氮素各性状指标变化幅度明显不同，说明品种之间对氮肥反应的敏感程度有差异。因此通过改变遗传因素和氮肥施用量可促进冬小麦花前同化物和氮素向籽粒的转移．提高籽粒产量和氮素利用效率。  相似文献   

18.
氮肥施用时期对马铃薯氮素积累与分配的影响   总被引：3，自引：0，他引：3  
以马铃薯克新13号脱毒种薯为材料,在相同氮肥用量下,设置不同生育时期施氮的田间小区试验,通过测定主要生育期植株各器官干物重和含氮量,研究施氮时期对马铃薯不同器官氮素积累、分配及块茎产量和质量的影响。结果表明,马铃薯在营养生长期的吸氮素量仅为全生育期的1/3,块茎形成中期达到马铃薯的吸氮高峰期,块茎增长后期至成熟期块茎中的氮素主要来自营养器官的二次分配。与N 150 kg/hm2全部做基肥相比,将1/3的氮在块茎增长初期追施可使商品薯产量提高25%(P<0.05),达到30.01 t/hm2。氮肥利用率达到44%(P<0.05)。适宜氮肥用量下,基肥和追肥的合理分配是获得马铃薯高产优质的重要条件,基肥氮不足,氮肥集中在苗后施用,则易导致植株贪青。试验在肥力中等的土壤种植马铃薯,150 kg/hm2氮素用量条件下,将2/3的氮作基肥施用,1/3的氮在块茎增长初期追施,较有利于养分在块茎中的分配,同时也能获得最高的块茎产量。  相似文献   

19.
The effect of cow slurry N on productivity and white clover content was compared with that of mineral fertilization in a natural grassland sward. Fertilizer was applied at two different N rates as split applications of ammonium nitrate, or as cow slurry (145 or 290 kg N ha−1 in the first year and 120 or 240 kg N ha−1 In the second year)- In the first year, fertilizer N produced higher dry matter (DM) yields than the slurry treatments. Nitrogen efficiency and clover content reduction were higher for the mineral treatments, the efficiency being lower for the higher rate of N application. In the second year, N supplied by the slurry gave the same productivity, N efficiency and white clover content reduction as that from the mineral N fertilization; higher efficiency in the second year being due to favourable weather conditions and low white clover contents. The high N efficiencies of the slurry compared with the fertilizer N treatments were attributed to the dilution of the slurry and to split applications over the year. Yield differences between treatments were due mainly to the grass component of the sward. Competition between grasses and other species, and white clover for mineral N resulted in a reduction in the white clover content in those treatments in which more N was supplied, whether it came from the mineralization of slurry or from the fertilizer N applied.  相似文献   

20.
To compare N uptake and use efficiency of rice among different environments and quantify the contributions of indigenous soil and applied N to N uptake and use efficiency, field experiments were conducted in five sites in five provinces of China in 2012 and 2013. Four cultivars were grown under three N treatments in each site. Average total N uptake was 10–12 g m?2 in Huaiji, Binyang, and Haikou, 20 g m?2 in Changsha, and 23 g m?2 in Xingyi. Rice crops took up 54.6–61.7% of total plant N from soil in Huaiji, Binyang, and Haikou, 64.3% in Changsha, and 63.5% in Xingyi. Partial factor productivity of applied N and recovery efficiency of applied N in Changsha were higher than in Huaiji, Binyang, and Haikou, but were lower than in Xingyi. Physiological efficiency of soil N and fertilizer N were lower in Changsha than in Huaiji, Binyang, and Haikou, while the difference in them between Changsha and Xingyi were small or inconsistent. Average grain yields were 6.5–7.5 t ha?1 (medium yield) in Huaiji, Binyang, and Haikou, 9.0 t ha?1 (high yield) in Changsha, and 12.0 t ha?1 (super high yield) in Xingyi. Our results suggest that both indigenous soil and applied N were key factors for improving rice yield from medium to high level, while a further improvement to super high yield indigenous soil N was more important than fertilizer N, and a simultaneous increasing grain yield and N use efficiency can be achieved using SPAD-based practice in rice production.  相似文献   

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