应用~(15)N 测定玉米对化肥氮素的利用率

1983～1984年设盆栽试验,供试土壤为棕黄土和草甸土,供试作物为玉米,~(15)N 肥料为硫酸铵。四个处理,三次重复。应用示踪法测定玉米对化肥的氮素利用率,草甸土为35.2～38.4%,棕黄土为34.7～44.5%。差减法测定氮素利用率比示踪法高20.7～39.7%、草甸土 AN 值为18.6～22.5mg/100g 土,棕黄土为16.0～20.9mg/100g 土。     

~(15)N测定甘蔗生物固氮能力研究(英文)

[Objective] The study aimed to reveal the biological nitrogen fixation capacity by sugarcane from Brazil under the ecological conditions of Guangxi,and to provide reference for study on the biological nitrogen fixation capacity by sugarcane and related generalization and application. [Method] The 15N isotopic fertilizer was solely applied on plants of three sugarcane cultivars planted in greenhouse with no other fertilizer forms applied,meanwhile virus-free stem seedling was regarded as control,to measure their biological nitrogen fixation capacity using 15N isotope. [Result] The nitrogen fixation rate of B8 from Brazil reached 26.91%,while Guitang 11 and RIC16 presented no or poor nitrogen fixation capacity. [Conclusion] The sugarcane cultivar B8 from Brazil showed some nitrogen fixation capacity under the ecological conditions of Guangxi.     

Estimates on nitrogen uptake in the subsequent wheat by above-ground and root residue and rhizodeposition of using peanut labeled with 15N isotope on the North China Plain

Leguminous crops play a vital role in enhancing crop yield and improving soil fertility. Therefore, it can be used as an organic N source for improving soil fertility. The purpose of this study was to (i) quantify the amounts of N derived from rhizodeposition, root and above-ground biomass of peanut residue in comparison with wheat and (ii) estimate the effect of the residual N on the wheat-growing season in the subsequent year. The plants of peanut and wheat were stem fed with ¹⁵N urea using the cotton-wick method at the Wuqiao Station of China Agricultural University in 2014. The experiment consisted of four residue-returning strategies in a randomized complete-block design: (i) no return of crop residue (CR0); (ii) return of above-ground biomass of peanut crop (CR1); (iii) return of peanut root biomass (CR2); and (iv) return of all residue of the whole peanut plant (CR3). The 31.5 and 21% of the labeled ¹⁵N isotope were accumulated in the above-ground tissues (leaves and stems) of peanuts and wheat, respectively. N rhizodeposition of peanuts and wheat accounted for 14.91 and 3.61% of the BG¹⁵N, respectively. The ¹⁵N from the below-ground ¹⁵N-labeled of peanuts were supplied 11.3, 5.9, 13.5, and 6.1% of in the CR0, CR1, CR2, and CR3 treatments, respectively. Peanut straw contributes a significant proportion of N to the soil through the decomposition of plant residues and N rhizodeposition. With the current production level on the NCP, it is estimated that peanut straw can potentially replace 104 500 tons of synthetic N fertilizer per year. The inclusion of peanut in rotation with cereal can significantly reduce the use of N fertilizer and enhance the system sustainability.     

用~(15)N示踪研究灌溉水平和氮磷配比对砂地小麦生长和氮素平衡的影响

15N示踪研究证明，在不同灌溉水平下，在细质砂土上，增施磷肥可以大幅度提高小麦单位面积穗数、穗粒数和产量。并可以促进小麦对N素的吸收，提高肥料N利用率，降低肥料N损失率，促进营养物质的运输和转化，但是小麦的千粒重和含N量则随之下降。增施磷肥的效果大于增施N肥。在中等灌溉水平下，每公顷施纯N204kg，施P2O3180kg，可以实现砂地小麦高产高效的统一。     

淹水土壤中秸秆氮素的转化

采用15N示踪技术和密闭培养法研究水稻和玉米秸秆15N在淹水土壤中的转化过程。结果表明 :土壤中秸秆15N的各转化过程相互制约 ,每个过程中15N含量都处于动态变化之中。秸秆种类和土壤类型对土壤矿质15N含量的影响随时间延长逐渐变小 ,培养 112d后土壤中矿质15N含量仅占加入秸秆15N的 0 96 %～ 1 6 8%。秸秆15N有 2 0 3%～ 4 2 5 %被微生物固持 ,0 2 3%～ 14 16 %被粘土矿物固定。粘土矿物类型影响土壤对秸秆15N的固定 ,变性土中固定态15NH 4含量明显高于红壤。秸秆15N的固定使其以气态形式损失的量减少 ,这在农业生产中将有助于保持土壤肥力。整个培养过程中秸秆15N的损失率为 2 9 70 %～ 46 30 %。 112d后秸秆15N实际矿化了 47 72 %～5 1 74% ,仍有 5 0 %左右的秸秆15N残留于土壤。     

应用~(15)N研究金丝小枣的吸氮规律

在微区条件下,通过春、夏、秋三个季节对金丝小枣施用~(15)N 标记的尿素,研究发现夏施时枣树能利用25%左右的肥料氮,且吸收速度很快,有利于当年果实的高产。秋施时 N 的利用率只有12%,近一半仍保留在土壤中,而春施约72%的 N 损失掉。春秋枣树的吸氮速度都较低,此时施用氮肥必然导致利用率低,经济效益也低。夏季是金丝小枣的最佳施氮时期。     

应用~(15)N示踪研究毛白杨苗木对不同形态氮素的吸收及分配

为探讨毛白杨苗木对不同形态氮素的吸收、分配及利用特性,以毛白杨新无性系83号插条苗为试材,于2007年3—9月在北京林业大学苗圃,应用15N示踪技术测定在相同施氮量下毛白杨苗木对硝态氮(NO3-15N)和铵态氮(NH4-15N)的吸收率、利用率及分配率等指标。结果表明:①施肥后28 d,苗木对两种氮肥的吸收利用达到最大值,其中,标记NO3-15N肥吸收率为0.36 g/株,利用率达35.98%;标记NH4-15N肥吸收率为0.15 g/株,利用率为14.53%。②苗木NO3-15N肥平均利用率(19.75%)约为NH4-15N肥(7.95%)的2.5倍。③施肥后各个时期,全株的NO3-15N肥Ndff值均显著大于NH4-15N肥。各器官对NO3-15N肥的征调能力明显高于NH4-15N肥,茎对肥料征调的竞争能力最强,其次为叶和根。④氮素分配率在各器官中差异显著(P<0.05),总体趋势为叶>根>茎。叶中NO3-15N的分配率均高于NH4-15N,根中储存的氮素主要供地上部分生长所需,总体呈逐渐下降的趋势,茎是氮素贮藏的"临时库",苗木主要通过茎将吸收的氮素输送到叶等生长旺盛的部位。     

有机无机复配肥氮肥利用率的15N生物示踪研究

采用盆栽大白菜15N示踪法研究不同复配比例有机无机复配肥的氮肥利用率.结果表明,有机无机复配肥氮肥利用率比全化肥复配肥明显提高6.5%～11.9%;大白菜产量提高9.0～32.6 g/盆,增产6.0%～21.7%.试验筛选出较佳的有机:无机复配比例为:27:73和47:53,N-P2O5-K2O总含量为15%～20%,大白菜化学氮肥利用率达到38.75%以上,肥料效应最大.     

应用~(15)N对棉田生态系统中氮素的吸收利用和去向的研究

应用15N示踪方法 ,研究了棉田生态系统中N的吸收利用和去向。证明在等N ,P ,K条件下 ,沼肥与化肥配施有利于N向生殖器官转移 ,其增产效果比单施化肥显著 ;绿肥与化肥配施和单施化肥产量基本持平。各处理棉株对土壤N的依赖性都低于肥料N ,约占 3 7.4 4%～ 4 3 .66% ,但单施化肥高于有机肥与化肥配施。棉株营养器官累积土壤N的比例各处理都大于生殖器官 ,而累积的肥料N正好相反 ,说明棉株生育前期对土壤N的依赖性较高 ,而后期对肥料N的依赖性较高 ,为棉花生产重施花铃肥提供了依据。有机肥与化肥配施肥料N在土壤中的残留率为单施化肥 2 .5～ 3倍 ,而损失率后者为前者的 1 .4～ 1 .6倍 ,其生态效益差异十分显著。     

不同氮肥水平对水稻15N吸收的影响（英文）

采用田间试验的方法,利用15N同位素示踪技术,研究了施氮对龙粳31和空育131两个水稻品种15N吸收与分配的影响。试验结果表明:植株生长前期水稻吸收的氮素的量最高;水稻籽粒中的15N累积分配量龙粳31高于空育131,而在茎秆龙粳31低于空育131;水稻吸收的氮在植株体内的重新分配和转运效率对龙粳31的产量增加有重要作用。     

利用~(15)N研究玉米-大豆套作体系中氮素利用特征

【目的】明确不同氮水平下玉米-大豆套作系统中氮素利用特征。【方法】通过~(15)N标记试验,研究了2种氮水平和3种种植模式下作物氮素吸收、土壤氮素残留与损失及大豆生物固氮量的影响。【结果】套作系统内(IMS)玉米植株总氮吸收量和~(15)N吸收量显著高于玉米单作(MM);IMS内的大豆总氮吸收量低于大豆单作(MS),而IMS内大豆的~(15)N吸收量较MS显著增加,且IMS内大豆的固氮比例及固氮量较MS显著增加。IMS中玉米和大豆对~(15)NH_4~+总吸收量显著高于~(15)NO_3~-,且其土壤中的~(15)N残留量~(15)NH_4~+均低于~(15)NO_3~-,~(15)N主要残留于0~40 cm土壤中。此外,IMS的~(15)N回收率显著高于各单作,~(15)N损失率低于各单作处理,且IMS的~(15)N回收率~(15)NH_4~+显著高于~(15)NO_3~-,~(15)N残留率~(15)NO_3~-显著高于~(15)NH_4~+,而~(15)N损失率无显著差异。【结论】与相应的单作相比,玉米-大豆套作显著提高了~(15)N回收率、残留率,降低了~(15)N损失率,增强了大豆生物固氮作用,是一种资源高效、环境友好的可持续农业种植模式。     

Strategies for timing nitrogen fertilization of pear trees based on the distribution,storage, and remobilization of ~(15)N from seasonal application of (~(15)NH_4)_2SO_4

In order to improve the management of nitrogen(N) fertilization in pear orchards, we investigated the effects of application timing on the distribution, storage, and remobilization of N in mature pear trees in a field experiment at Jingtai County, Gansu Province, China. Nine trees were selected for the experiment and each received equal aliquots of 83.33 g N in the autumn, spring, and summer, with ~(15)N-labeled(NH_4)_2SO_4 used in one of the aliquots each season. Results showed that the(~(15)NH_4)_2SO_4 applied in the autumn remained in the soil during the winter. In the following spring this N was absorbed and rapidly remobilized into each organ, especially new organs(leaves, fruit and new shoots). The ~(15)N supplied in spring was rapidly transported to developing fruit between the young fruit and fruit enlargement stages. ~(15)N from the summer application of fertilizer was mainly stored in the coarse roots over the winter, then was mobilized to support growth of new organs in spring. In conclusion, for pear trees we recommend that the autumn application of N-fertilizer be soon after fruit harvest in order to increase N stores in fine roots. Spring application should be between full bloom and the young fruit stages to meet the high N demands of developing fruit. Summer application of fertilizer at the fruit enlargement stage does not contemporaneously affect the growth of pears, but increases the N stored in coarse roots, and in turn the amount available for remobilization in spring.     

Millet/peanut intercropping at a moderate N rate increases crop productivity and N use efficiency,as well as economic benefits,under rain-fed conditions

Cereal and legume intercropping has been widely adopted to increase crop productivity in sustainable farming systems worldwide.  Among different intercropping combinations, millet and peanut intercropping can be adapted to most water-limited areas.  However, there are few studies on the differences in yield characteristics and nitrogen use efficiency between millet/peanut intercropping and monocultures under different nitrogen (N) application rates.  The objective of this study was to determine the yield advantages and economic benefits, as well as the appropriate N application rate, of millet/peanut intercropping.  A two-year field experiment was conducted with three cropping patterns (monoculture millet, monoculture peanut and millet/peanut intercropping) and four N rates (0, 75, 150 and 225 kg ha⁻¹).  The results showed that the land equivalent ratio (LER) and net effect (NE) of the intercropping system reached their highest levels at the N input of 150 kg ha⁻¹ in 2018 and 2019 (1.04 for LER, 0.347 Mg ha⁻¹ for NE, averaged across two years).  Millet was the dominant crop in the intercropping system (aggressivity of millet and peanut (Amp)>0, competitive ratio of millet and peanut (CRmp)>1), and millet yields achieved their highest values at N inputs of 225 kg ha⁻¹ for monoculture and 150 kg ha⁻¹ for intercropping.  NUE reached its highest levels with N inputs of 150 kg ha⁻¹ for all planting patterns over the two years.  Intercropping combined with an N input of 150 kg ha⁻¹ achieved the highest net income of 2 791 USD ha⁻¹, with a benefit-cost ratio of 1.56, averaged over the two years.  From the perspective of economics and agricultural sustainable development, millet/peanut intercropping at 150 kg N ha⁻¹ seems to be a promising alternative to millet or peanut monoculture.     

施氮量对甘蔗氮素吸收与利用的影响

在土壤低氮(碱解氮68.85 mg/kg)条件下,以新台糖22号(ROC22)为试材,分别施用15N标记的尿素2.5、5.0、7.5 g/盆,研究了氮肥施用量对甘蔗氮素吸收与利用的影响。结果表明,随着氮肥施用量的增加,甘蔗干物质积累、氮素积累、来源于肥料氮素的比率及土壤有效氮含量不同程度增加,但甘蔗氮肥利用率显著下降;施氮量明显影响甘蔗各器官的干物质分配、氮素分配、氮肥利用率及氮素在不同土层的分布;甘蔗主要吸收20~40 cm土层的氮素。甘蔗施用氮肥应考虑适宜的量和土层深度。     

控释肥对基质栽培番茄产量、品质及养分利用率的影响

【目的】研究控释肥不同用量对基质栽培番茄产量、品质及养分利用率的影响,确定其适宜的控释肥施用量.【方法】采用基质槽栽培方式,试验处理包括:不施肥处理(CK)、常规施肥处理(CF)、控释肥处理(CRF与CF总养分量相同)、N减量20%控释肥处理(CRF20)、N减量40%控释肥处理(CRF40)及N减量60%控释肥处理(CRF60).【结果】与CF相比,CRF20、CRF40的番茄各生育期的叶片净光合速率、蒸腾速率和气孔导度显著增大,胞间CO2浓度显著减小;CRF20、CRF40较CF氮、磷、钾的利用率分别提高10.1%、15.4%,9.7%、12.5%和6.1%、10.0%,氮、磷、钾的积累量分别增加24.62%、27.09%,44.84%、57.84%和12.31%、20.21%,分别增产10.68%、36.03%;CRF40可显著提高可溶性糖含量,降低硝酸盐和有机酸含量.【结论】以控释肥替代尿素,在施N量减少40%的情况下在获得最高产量的同时,显著地改善了番茄品质.     

高肥力稻田不同施氮水平下的氮肥效应和几种氮肥利用率的研究

研究了浙北地区高肥力稻田不同施氮水平下的氮肥效应和氮素利用情况.结果表明:不同施氮量下的水稻产量、渗漏水含氮量、土壤含氮量的氮肥效应明显,施氮量在150～225 kg·hm-2时产量没有显著差异,而渗漏水含氮量、土壤含氮量在施氮超过225 kg·hm-2水平下,迅速增加,有引起氮素面源污染的较大危险.氮肥利用率和生产力的结果说明,浙北地区的氮肥利用率普遍较低,氮肥吸收利用率平均只有21.55%,氮肥农学利用率在7 kg·kg-1以下,氮肥的生理利用率不到20 kg·kg-1,大大低于全国平均水平.在考虑氮肥利用率的基础上运用边际收益分析原理得出140～200 kg·hm-2可能是浙北高肥力稻田较理想的施氮水平.     

红蓝光下光强对生菜电能、光能利用效率及品质的影响

通过调查红蓝LED光源下生菜的光能利用效率(LUE)和电能利用效率(EUE),以期确定人工光栽培环境下红蓝LED的优化光强参数。本试验LED光源的红蓝光配比设定为1∶1,光强分别为200、300和400μmol/(m2·s)的3个处理(分别以L200、L300和L400表示),生菜定植38d后收获。结果表明:1)定植至收获期间,对每次间苗所收获生菜的干重以及定植38d后收获生菜的干重进行累计计算,处理L300下生菜的EUE最大,为0.948%,较处理L200和L400下生菜的EUE分别高5.22%和46.6%;处理L200下生菜的LUE最大,为4.17%,较处理L300和L400下生菜的LUE分别高12.0%和59.3%。2)定植38d后处理L300下生菜地上部分的鲜干重最大,平均值分别为41.3和2.58g,较处理L200和L400下地上部分鲜重分别高23.5%和25.2%;地上部分干重分别高28.4%和12.8%。3)处理L300与处理L200相比,定植38d后前者叶片的可溶性糖含量较高,硝酸盐含量较低;但与处理L400之间无显著性差异。综合考虑光能、电能利用效率及干重累积量,推荐300μmol/(m2·s)作为红蓝LED组合光源下生菜生长较优的光照强度。     

施氮次数对甘蔗干物质积累、产量及品质的影响

以新台糖22号(ROC22)为试材,以不施氮肥为对照,设T1(尿素5 g/盆作基肥1次施用)、T2(尿素作基肥2.5 g/盆和分蘖肥2.5 g/盆2次施用)及T3(尿素作基肥1.5 g/盆、分蘖肥1.5 g/盆和攻茎肥2 g/盆3次施用)3个处理,研究了氮肥不同施用次数对甘蔗干物质积累、产量及品质的影响。结果表明,随氮肥施用次数的增加,甘蔗干物质积累量、产量及产糖量显著增加,但蔗糖分含量略有下降;氮肥不同施用次数对甘蔗各器官、各生长阶段干物质积累的影响有明显差异。     

氯离子对马铃薯同化~(14)CO_2及吸收~(32)P和~(15)NO_3~-的影响

采用同位素示踪技术,研究了Cl对马铃薯的同化作用及吸收养分的影响。结果表明,培养液中Cl浓度过高会影响马铃薯对~(14)CO_2同化,减少对~(15)NO_5和H_2 ~(32)PO_4PO_4的吸收。