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1.
巢湖地区水稻氮肥利用率和最大经济效益施氮量的研究 总被引：2，自引：1，他引：1
田间条件下,对皖稻52和宁粳3号在不同施氮水平(0、60、120、180、240和300 kg·hm-2)下的产量、氮素吸收、累积及利用率进行研究。结果表明,施氮量超过180 kg·hm-2后,水稻产量增加较少,超过240 kg·hm-2,水稻产量开始下降。当施氮量从60 kg·hm-2增加到300 kg·hm-2,皖稻52和宁粳3号的氮肥表观利用率(REN)分别为75.1%~49.4%和62.1%~50.2%;氮肥农学利用率(AEN)也随施氮量的增加而显著下降,为17.3~7.33 kg·kg-1和16.8~8.64 kg·kg-1。通过拟合水稻产量、经济效益与施氮量的回归方程计算,水稻皖稻52和宁粳3号的最大经济效益施氮量分别为178 kg·hm-2和190 kg·hm-2。此时,水稻可维持较高的产量和保持较高的氮肥利用率。 相似文献
2.
《河南农业大学学报》2014,(3)
为了解强筋小麦西农979高产高效生产需水需肥规律,为其高产高效标准化栽培提供依据.在大田条件下,研究了冬小麦品种西农979在不同水氮耦合条件下小麦花后旗叶叶绿素含量、光合速率的变化,灌水和氮肥利用率以及最终产量和产量构成要素的表现.结果表明,中水中氮(W2N2)和中水高氮(W2N3)水肥耦合有利于小麦花后维持较高的旗叶叶绿素含量和光合速率.较长时间保持高叶绿素含量和高光合速率;在0~300 kg·hm-2的施氮量范围内,小麦产量随着施氮量的增加而增加,氮肥效率表现出先增加后降低的规律;随着灌水量的增加,小麦产量先增加后降低,水分利用效率随着灌水量的增加而降低;本试验条件下,W2N3(灌水量为田间持水量60%+300 kg·hm-2施氮量)处理产量最高,为8 648.49 kg·hm-2,W2N2处理(灌水量为田间持水量60%+150 kg·hm-2施氮量)产量为7 944.14 kg·hm-2,相比最高产降低8.87%,差异不显著,但W2N2处理下的氮肥农学效率最高,并且显著高于其他处理,因此,W2N2为本试验条件下最为高效的施肥灌水处理. 相似文献
3.
不同施氮量对两系杂交中籼稻产量和衰老的影响 总被引：1，自引：0，他引：1
以超高产水稻品种丰两优香1号为材料,在常规大田生产条件下,分析不同氮肥用量对两系杂交中籼稻产量、氮肥农学利用效率以及功能叶衰老的影响。结果表明,施氮量在0~255 kg·hm-2范围内,两系稻产量、群体质量和氮肥农学利用效率随施氮量增加而提高,以255 kg·hm-2施氮处理的产量最高(11786.4 kg·hm-2)、氮肥农学利用率最大;施氮量增加到300 kg·hm-2,产量、群体质量和氮肥农学利用率均下降。氮素营养影响水稻衰老进程,适宜施氮量(255 kg·hm-2)和较高氮肥农学利用率,能保证两系杂交中籼稻齐穗后功能叶不早衰,有利于后期植株光合能力提高和光合产物积累,使后期物质积累贡献率提高,为获得高产奠定基础。 相似文献
4.
夏闲期连续两年种植并翻压豆科绿肥对旱地冬小麦生长和养分吸收的影响 总被引：3，自引：0，他引：3
通过2a田间定位试验,研究渭北旱塬地区夏闲期插播并翻压不同豆科绿肥(长武怀豆、大豆和绿豆,夏休闲为对照)和施氮量(0、108、135、162 kg·hm-2)对冬小麦生长及养分吸收的影响.结果表明:与休闲相比,连续2 a夏闲期种植并翻压豆科绿肥不但能显著提高冬小麦分蘖数、总茎数、产量、植株氮磷钾养分质量分数和吸收量,而且还能提高小麦单位面积穗数.夏季休闲时,连续2a不施氮肥与施用氮肥(108、135、162kg·hm-2)相比,冬小麦产量显著降低.然而,夏闲期种植并翻压长武怀豆和大豆时,连续2 a不施氮肥与施用氮肥(108、135、162 kg·hm-2)相比,冬小麦并没有明显减产;此外,施氮量108、135和162 kg·hm-2处理间小麦产量没有显著差异. 相似文献
5.
基于稻草还田的氮肥优化管理研究 总被引：3，自引：0，他引：3
采用田间试验比较研究了在水稻秸秆还田环境下不同施氮模式对土壤N素供应、氮肥利用率及其对水稻生产力的影响。结果表明,稻草还田改善了土壤的供氮能力,不论在背景氮较低的砂性土壤上还是在背景氮较高的粘性土壤上,稻草还田配施减量氮肥(N1、N3处理全年施氮量180kg.hm-2,其中桃江主试验中N1处理早稻施氮80kg.hm-2,60%为基肥,40%为分蘖肥施用;晚稻施氮105kg.hm-2,50%为基肥,40%为分蘖肥,10%为穗肥施用;桃源氮替代试验中N1、N3处理早稻施氮81kg.hm-2,晚稻施氮99kg.hm-2,N1处理早、晚稻氮肥施用分配比例为基肥30%,分蘖肥30%,穗肥40%,N3处理早稻氮肥50%为基肥,50%为分蘖肥施用,晚稻氮肥50%为基肥,40%为分蘖肥,10%为穗肥施用)处理,相对于移走稻草 高量氮肥(N2处理其中桃江主试验早稻施氮量115kg.hm-2,晚稻施氮量为150kg.hm-2,分别以60%为基肥,40%为分蘖肥施用;桃源氮替代试验早稻施氮量为108kg.hm-2,50%为基肥,50%为分蘖肥施用,晚稻施氮量为132kg.hm-2,50%为基肥,40%为分蘖肥,10%为穗肥施用)处理之间稻田系统生产力无显著差异,但每年节约60～80kg纯氮化肥的投入,提高了其边际成本报酬率。分次施氮的效果表明,稻草还田下等量氮肥不同施氮模式(N1、N3)处理之间,水稻产量差异不显著,但水稻吸氮高峰集中在分蘖旗至孕穗期,N1模式减少了基肥施氮量,防止了因作物未能及时吸收导致的土壤速效氮的损失,而适当增加作物后期施氮量又能有效缓减作物后期生长大量吸氮的要求与微生物分解稻草固持矿质氮之间的矛盾,改善了土壤的供氮状况,其效果最优。因此,在全年稻草还田量为7500kg.hm-2的红壤稻田系统,根据投入氮肥的边际收益,全年适宜配施氮量为180kg.hm-2,且各时期施氮量优化比例为基肥30%、分蘖肥30%、穗肥40%。 相似文献
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7.
以秀水110和秀水114为供试水稻品种,在田间条件下研究了金正大硫磺加树脂双层包膜尿素(SPCU)不同用量对水稻产量的影响。结果表明,水稻产量和控释氮肥用量呈显著或极显著二次多项式相关。新湾试验点,SPCU折N 300 kg.hm-2产量最高,比对照增加46.6%。戴村试验点,SPCU折N 270 kg.hm-2产量最高,比对照增加19.3%。回归分析表明,控释氮肥在新湾点最大施氮量为262 kg.hm-2,最佳施氮量为246kg.hm-2;戴村点最大施氮量为246 kg.hm-2,最佳施氮量为212 kg.hm-2。 相似文献
8.
《天津农业科学》2016,(6)
通过不同氮肥水平的田间小区试验,设计了施氮的5个水平,分别测定了蒲公英产量及品质指标,研究施氮肥对蒲公英产量及品质的影响。结果表明,施氮量为160 kg·hm-2时蒲公英达到最高产量1 291.24 kg·hm-2。施氮量超过160 kg·hm-2时产量逐渐降低;叶绿素含量随施氮量的增加而增加,在施氮肥320 kg·hm-2时叶绿素达最高55.32;适量施用氮肥能显著提高蒲公英的VC、总糖、粗蛋白的含量;当施氮量为240 kg·hm-2时蒲公英的VC和总糖含量最高,分别为11.57 mg·g-1和19.77%,施氮量为160 kg·hm-2时粗蛋白含量达最高值0.16 mg·g-1;从结果中可知人工种植蒲公英的施氮量在160~240 kg·hm-2之间品质和产量达到最佳。 相似文献
9.
基于GIS的吉林省水稻种植区施氮效果及减排潜力分析 总被引：2，自引：0，他引：2
【目的】研究不同水稻种植区施氮效果差异,旨在加强氮肥精准养分管理,提高作物产量和肥料效率,从而减少农田氮排放。【方法】通过对2005—2013年吉林省测土配方施肥田间试验中不施氮肥处理(N0P2K2)及3个氮梯度(0.5N_2P_2K_2)、(N_2P_2K_2)、(1.5N_2P_2K_2)处理进行分析,研究不同水稻种植区的产量、氮肥施用效果及氮肥农学利用率,探讨各区域施氮效果及减排潜力。【结果】吉林省各地区水稻产量差异显著,西部地区最高,东部地区最低。在不施氮肥条件下西部地区平均产量可达7.6 t·hm-2,其与中部地区和东部地区的平均产量差可达到2.1和2.2 t·hm-2。施用氮肥后,中部和东部地区最低增产率29.8%(最高59.5%)显著高于西部地区12.6%(最高29.4%)。中部和东部的氮肥利用效率分别为12.2—19.7和12.5—19.5 kg·kg-1,远高于西部地区的8.8—13.1 kg·kg-1。采用最大经济收益法MRTN方法建立氮肥用量与净收益间的函数关系,从而计算各地区最佳施氮量。西部地区、中部地区和东部地区的最佳施氮量分别为114.9、128.9和134.1 kg·hm-2,与推荐施肥相比可减少25.6、18.3和5.3kg·hm-2。在产量没有显著差异的条件下,各地区均可减少氮肥施用量,尤其是西部和中部地区。通过节氮成本和粮食收入核算发现,各地区均可增加经济效益,其中中部地区农民增收显著。在保证产量条件下,采用最佳施肥量,吉林省西部、中部和东部每年可减少氮投入量分别为4 378、7 064和604 t;减少氮排放98.2、158.6和13.6 t。【结论】吉林省西部地区应控制氮肥施用;中部地区为全省减排重点区域;东部地区目前施肥量适中,可以配合其他管理模式消减自然因素的限制,从而提高水稻产量。 相似文献
10.
以弱筋小麦扬麦22为研究对象,采取田间裂区试验,研究播期、密度和施氮量对其产量、品质及氮肥农学利用率的影响。结果表明:播期和密度对产量均有显著影响,11月4日播种和225万苗·hm-2密度处理产量最高,施氮量对产量无显著影响,千粒重是扬麦22产量形成的关键因子;籽粒蛋白质含量和氮肥农学利用率受播期和施氮量影响,11月19日播种的籽粒蛋白质含量和氮肥农学利用率最高,施氮量增加,籽粒蛋白质含量显著升高,氮肥农学利用率降低。11月4日播种、225万苗·hm-2密度、180kg·hm-2施氮量处理,弱筋小麦扬麦22产量和品质较为协调,产量可达7 343kg·hm-2,籽粒蛋白质含量达12.37%,氮肥农学利用率达12.43kg·kg-1。 相似文献
11.
合理施肥是保证作物高产、减少面源污染的重要措施,以华北平原为研究区域,基于7个长期施肥试验,探讨不同施氮量及施肥模式（不施肥CK、化肥NPK、有机肥M、有机无机配施NPKM）对作物产量及氮肥利用率的影响。结果表明,作物产量与施肥量之间整体呈抛物线趋势,作物产量最高值均出现在NPKM处理。不同施肥模式对作物产量有一定影响,NPKM与NPK处理小麦产量无显著差异,且显著高于M、CK处理;NPKM、NPK、M处理玉米产量无显著差异,均显著高于CK处理。氮肥利用率随着施氮量增加呈下降趋势,不同施肥模式对氮肥利用率有一定影响,小麦季NPKM与NPK处理氮肥利用率无显著差异,且高于M处理,玉米季NPKM、NPK、M处理之间氮肥利用率均无显著差异。综合分析施氮量与有机肥替代率两因素对小麦产量的影响,在华北平原,利用有机肥替代化肥潜力可观,且不会显著降低作物产量,甚至增产,但为避免显著减产,在考虑提高有机肥替代率时,需要满足总施氮量的需求。 相似文献
12.
Impacts of Fertilization Alternatives and Crop Straw Incorporation on N2O Emissions from a Spring Maize Field in Northeastern China 总被引：1，自引：0，他引：1 
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下载免费PDF全文 Spring maize is one of the most popular crops planted in northeastem China. The cropping systems involving spring maize have been maintaining high production through intensive management practices. However, the high rates of nitrogen （N） fertilizers application could have introduced a great amount of nitrous oxide （N2O） into the atmosphere. It is crucial for sustaining the maize production systems to reduce N2O emissions meanwhile maintaining the optimum yields by adopting alternative farming management practices. The goal of this study was to evaluate effects of alternative fertilization and crop residue management practices on N2O emission as well as crop yield for a typical maize field in northeastern China. Field experiments were conducted during the 2010-2011 maize growing seasons （from early May to late September） in Liaoning Province, northeastern China. N2O fluxes were measured at the field plots with six different treatments including no N fertilizer use （CK）, farmers＇ conventional N fertilizer application rate （FP）, reduced N fertilizer rate （OPT）, reduced N fertilizer rate combined with crop straw amendment （OPTS）, slow-release N fertilizer （CRF）, and reduced N fertilizer rate combined with nitrification inhibitor （OPT＋DCD）. The static chamber method combined with gas chromatography technique was employed to conduct the measurements of N2O fluxes. The field data showed that N2O emissions varied across the treatments. During the maize growing season in 2010, the total N2O emissions under the treatments of CK, FP, OPT, OPTS, and CRF were 0.63, 1.11, 1.03, 1.26, and 0.98 kg N ha-1, respectively. The seasonal cumulative N2O emissions were 0.54, 1.07, 0.96, 1.12, and 0.84 kg N ha1, respectively, under CK, FP, OPT, OPTS, and OPT＋DCD in 2011. In comparison with FP, CRF or OPT＋DCD reduced the N2O emissions by 12 or 21%, respectively, while the crop yields remained unchanged. The results indicate that the reduction of N-fertilizer application rate in combination with the slow-release fertilizer type or nitrification inhibitor could effectively mitigate N2O emissions from the tested field. The incorporation of crop residue didn＇t show positive effect on mitigating N2O emissions from the tested cropping system. The field study can provide useful information for the on-going debate on alternative N fertilization strategies and crop straw management in China. However, further studies would be needed to explore the long-term impacts of the alternative management practices on a wide range of environmental services. 相似文献
13.
蚯蚓在自然土壤中既能促进植物氮(N)素利用、增加土壤N固持,也会导致土壤N素气逸和淋溶损失,但农田土壤中持续的N肥施用如何影响蚯蚓的这些作用却并不清楚。因此,本研究提取了52篇文献中的202对数据,利用Meta分析从N肥类型、施肥量和施肥方式3个方面进行研究,评估N肥施用下蚯蚓活动对农田N转化的影响。总体结果表明,N肥施用下蚯蚓活动显著增加了作物生物量(地上部、地下部分别增加了12.00%、19.30%)及作物总氮(TN)含量(地上部、地下部分别增加了20.35%、21.06%),显著增加了土壤可利用N(9.16%)、微生物生物量氮(MBN,23.19%)及脲酶活性(23.73%),但与此同时也导致土壤氧化亚氮(N2O)排放和N淋溶增加了16.41%和16.15%。蚯蚓活动对不同肥料类型、施肥量及施肥方式下土壤N转化过程的影响不同。有机-无机N肥配施时,蚯蚓活动对作物生物量和TN含量均有显著的促进作用(地上部、地下部生物量分别增加了17.90%、18.03%;地上部、地下部TN含量分别增加了37.62%、25.76%);无论N肥施用量为多少,蚯蚓活动均显著增加了作... 相似文献
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以天优华占为材料,头季设置5个氮肥水平(N0:0kg·hm~(-2)、N1:69.00kg·hm~(-2)、N2:138.00kg·hm~(-2)、N3:207.00kg·hm~(-2)、N4:276.00kg·hm~(-2)),再生季统一施用氮肥160.50kg·hm~(-2),研究其对再生稻头季光合物质生产、两季产量及其构成因素的影响。结果表明,施用氮肥增加头季分蘖数和干物质积累,促进贮藏物质向籽粒的转运,过量施用氮肥会降低氮素农学利用效率。与N0处理相比,施用氮肥处理头季产量增加了12.12%~23.35%,N3处理最高。穗数随氮肥用量增加而增加,穗粒数则先增加后减少。再生季产量N4处理较0kg·hm~(-2)氮肥处理减少4.73%,其余处理产量增加1.61%~5.54%。再生季产量结构表现为穗数随头季氮肥增加呈减少趋势,穗粒数逐渐增加。试验表明,在福建中部山区条件下,天优华占再生季施用氮肥160.50kg·hm~(-2)条件下,头季氮肥用量为174.12kg·hm~(-2)最佳,可以充分发挥头季产量潜力,同时对再生季产量无显著影响,实现两季高产目标。 相似文献
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土壤温室气体排放对C/N的响应 总被引：4，自引：3，他引：1
土壤碳氮比(C/N)是影响微生物活动导致土壤温室气体排放和养分有效性变化的关键因素,秸秆还田配施氮肥则是调节农田土壤C/N的重要措施。为了探讨土壤C/N对温室气体排放的影响,通过在土壤中添加等量秸秆配以不同数量N素,在室内培养条件下测定分析了土壤不同起始C/N条件下土壤温室气体排放和活性碳氮的变化动态。研究发现:不同C/N条件下,土壤温室气体排放和溶解性有机碳(DOC)、溶解性有机氮(DON)的变化趋势基本一致。土壤CO_2排放速率和DOC含量均表现为随培养时间的延长逐渐降低,培养前30 d下降幅度较大,30~75 d降低缓慢,75 d后基本平稳;土壤N_2O的排放速率和DON含量则表现为先升高后降低,N_2O的排放速率在第7 d达到最大后逐渐降低直至平稳,土壤DON含量在第14 d达到最高后逐渐降低。土壤起始C/N越低,有机碳矿化率和净氮硝化速率越高,CO_2和N_2O排放量越多;土壤CO_2和N_2O的排放速率及累积排放量不但与土壤DOC和DON含量显著相关,而且与土壤DOC/DON比值显著相关。土壤硝态氮的含量变化表现为与土壤起始C/N相关,当土壤起始C/N在20~30时,硝态氮先升高后降低;土壤起始C/N大于40时,硝态氮先降低后升高。结果表明:在实际生产中,秸秆还田后合理配施氮肥调节土壤C/N是减少温室气体排放、提高作物氮肥利用效率的重要措施,为了掌握适宜的配施量和施用时期,有必要针对不同作物农田系统继续进行田间试验研究。 相似文献
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Optimal management of nitrogen fertilizer in the main rice crop and its carrying-over effect on ratoon rice under mechanized cultivation in Southeast China 下载免费PDF全文
下载免费PDF全文 HUANG Jin-wen WU Jia-yi CHEN Hong-fei ZHANG Zhi-xing FANG Chang-xun SHAO Cai-hong LIN Wei-wei WENG Pei-ying Muhammad Umar KHAN LIN Wen-xiong 《农业科学学报》2022,21(2):351-364
This study attempted to clarify the carrying-over effect of different nitrogen treatments applied to the main crop on the crop population growth and yield formation of ratoon rice under mechanized cultivation in Southeast China. Based on the constant total nitrogen application amounts (225.00 kg ha–1) in the main crop, an experiment with different ratios of basal and topdressing nitrogen fertilizer (the ratio of basal fertilizer:primary tillering fertilizer:secondary tillering fertilizer:booting fertilizer at 3:1:2:4 (N1), 3:2:1:4 (N2), 3:3:0:4 (N3), and 4:3:0:3 (N4), respectively, and a control without nitrogen treatment (N0)) was set up across two consecutive years in field using hybrid rice variety Yongyou 1540 as the test materials. The results showed that the total tiller number and effective tillering percentage increased in the main crop under the N1 treatment, more nitrogen fertilizer applied in late growth stage of the main crop, and its effective tillering percentage of the main crop was the highest at up to 70.18%, which was 9.15% higher than that of conventional fertilization treatment (N4), more nitrogen fertilizer applied in early growth stage of the main crop. The same tendency was observed in leaf area index (LAI) value of the main crop and its subsequent ratoon rice, which were 16.52 and 29.87% higher, respectively, in the N1 treatment than that in the N4 treatment at the full heading stage. The same was true in the case of the transport rates of stem and sheath dry mater and the canopy light interception rates in both the main and its ratoon crops. The transport rate of stem and sheath in main crop rice under N1 treatment increased by 50.57% compared with N4 treatment. The canopy light interception rate of N1 treatment increased by 5.07% compared with N4 treatment at the full heading stage of the ratoon crop. Therefore, the total actual yield was the highest in the main and its ratoon crops under N1 treatment, averaging 17 351.23 kg ha–1 in two-year trials, which was 23.00% higher than that in the conventional fertilization treatment (N4). The results showed that appropriate nitrogen treatment was able to produce a good crop stand in the main crop, which was essential for producing a good ratoon crop population and high yield especially under mechanized cultivation with low stubble height of the main crop. The study suggested that shifting the proper nitrogen application amounts to the late growth stage of the main crop, such as N1 treatment, not only had a higher productive effect on ensuring the yield of the main crop, but also had a positive effect on the axillary bud sprouts from the stubbles for ratoon rice, resulting in an increased percentage of productive panicles and achieving the goal of one planting with two good harvests under the conditions of our study. 相似文献
18.
Feng-lian LÜ Miao-miao HOU Hong-tao ZHANG Asif Khan Muhammad Ayaz Ciren QIANGJIU Chang-lu HU Xue-yun YANG Ben-hua SUN Shu-lan ZHANG 《农业科学学报》2019,18(1):169-178
A high crop yield with the minimum possible cost to the environment is generally desirable. However, the complicated relationships among crop production, nitrogen (N) use efficiency and environmental impacts must be clearly assessed. We conducted a series of on-farm N application rate experiments to establish the linkage between crop yield and N2O emissions in the Guanzhong Plain in Northwest China. We also examined crop yield, partial factor productivity of applied N (PFPN) and reactive N (Nr) losses through a survey of 1 529 and 1 497 smallholder farms that grow wheat and maize, respectively, in the region. The optimum N rates were 175 and 214 kg ha–1 for winter wheat and summer maize, respectively, thereby achieving the yields of 6 799 and 7 518 kg ha–1, correspondingly, with low N2O emissions based on on-farm N rate experiments. Among the smallholder farms, the average N application rates were 215 and 294 kg ha–1 season–1, thus producing 6 490 and 6 220 kg ha–1 of wheat and maize, respectively. The corresponding PFPN values for the two crops were 36.8 and 21.2 kg N kg–1, and the total N2O emissions were 1.50 and 3.88 kg ha–1, respectively. High N balance, large Nr losses and elevated N2O emissions could be explained by the overdoses of N application and low grain yields under the current farming practice. The crop yields, N application rates, PFPN and total N2O for wheat and maize were 18 and 24% higher, 42 and 37% less, 75 and 116% higher, and 42 and 47% less, correspondingly, in the high-yield and high-PFPN group than in the average smallholder farms. In conclusion, closing the PFPN gap between the current average and the value for the high-yield and high-PFPN group would increase crop production and reduce Nr losses or the total N2O emissions for the investigated cropping system in Northwest China. 相似文献
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Grain yield and nitrogen use efficiency of an ultrashort-duration variety grown under different nitrogen and seeding rates in direct-seeded and double-season rice in Central China 下载免费PDF全文
下载免费PDF全文 WANG Xin-yu YANG Guo-dong XU Le XIANG Hong-shun YANG Chen WANG Fei PENG Shao-bing 《农业科学学报》2023,22(4):1009-1020
Nitrogen(N) and seeding rates are important factors affecting grain yield and N use efficiency(NUE) in directseeded rice. However, these factors have not been adequately investigated on direct-seeded and double-season rice(DDR) in Central China. The objective of this study was to evaluate the effects of various N and seeding rates on the grain yield and NUE of an ultrashort-duration variety grown under DDR. Field experiments were conducted in 2018 in Wuxue County and 2019 in Qichun County, Hubei... 相似文献
20.
潮褐土冬小麦-夏玉米轮作体系氮肥后效及去向研究 总被引：9，自引：1，他引：9
【目的】在华北平原地区,研究肥料氮在两个轮作季四茬作物中的后效和去向。【方法】采用田间微区15N示踪试验,前茬设置5个氮素水平：0、75、150、225、300 kgN•hm-2（表示为N0、N75、N150、N225、N300）,副处理为小麦品种：科农9204和河农822,共计10个处理。【结果】在该试验条件下,后三茬作物均能吸收利用第一茬冬小麦残留在土壤中的15N标记肥料。第二茬夏玉米、第三茬冬小麦和第四茬夏玉米对残留15N的利用率分别为6.5%-14.1%、0.9%-2.9%和1.2%-1.6%。四茬作物的叠加利用率显著高于氮肥当季利用率,N75、N150、N225和N300处理叠加利用率分别是53.8%、58.7%、58.6%和55.8%（第一茬为河农822小麦品种）;60.0%、61.3%、60.9%和55.2%（第一茬为科农9204小麦品种）。经过四季作物种植后,土壤剖面中仍有22.3-96.2 kgN•hm-2的氮素残留,残留率为22.1%-32.8%,累积总损失量可达9.3-55.3 kgN•hm-2,损失率为8.9%-18.6%。【结论】在小麦当季,高施氮量条件下肥料主要残留在土壤中,后茬作物可以吸收土壤残留氮肥。土壤中15N含量随施氮量的增加而增加,随着茬口的增多有垂直向下运移的趋势,第一茬作物品种间无显著差异。 相似文献