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Effects of different N sources on growth, nutrient uptake and ionic balance of Larlix gmelini seedlings 被引量:1
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作者 陈永亮 韩士杰 苏宝玲 《Journal of Forestry Research》 SCIE CAS CSCD 2001年第3期153-156,209,共4页
The effect of different sources and levels of N on dry matter production, nutrient uptake and ionic balance ofLarlix gmelini was studied. The results showed that the growth of the plants fertilized with ammonium was n... The effect of different sources and levels of N on dry matter production, nutrient uptake and ionic balance ofLarlix gmelini was studied. The results showed that the growth of the plants fertilized with ammonium was not as good as the control treatment. The growth of the plants fertilized with ammonium nitrate did not differ significantly from that in control or nitrate treatment, but was better than that in the ammonium treatment. Total cation concentrations in shoots varied little with N level in the ammonium and ammonium nitrate treatments, while those in the shoot increased with N level in the nitrate treatment. The treatments had little effect on the anion concentrations in the shoot. In the roots, the concentrations of both cations and anions changed little except for SO4 2? and Ca2+. There existed a higher carboxylate production in the plants fertilized with nitrate. The ratio between the production of carboxylate and the production of organic N Δ(C-A)/ΔNorg was constant with N supply in the plants receiving nitrate, but obviously declined with N supply for ammonium-fed plants. Δ (C-A)/ΔNorg values were intermediate between those of the nitrate and the ammonium-fed plants as for the mixed N source. 展开更多
关键词 n resource GROWTH nutrient uptake Ionic balance
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Balance of Manure and Farmland Load in a Breeding Farm
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作者 胡春明 刘平 《Agricultural Science & Technology》 CAS 2012年第6期1350-1352,共3页
[Objective] The aim was to research balance between manure of breeding farm and farmland load. [Method] N balance of farmlands after manure fertilized was researched in a hoggery in Beijing (600 base sows and 647 bre... [Objective] The aim was to research balance between manure of breeding farm and farmland load. [Method] N balance of farmlands after manure fertilized was researched in a hoggery in Beijing (600 base sows and 647 breeding pigs). [Result] The suitable N input in neighboring farmlands was 191.9 kg/(hm 2 ·y) and the farmland area satisfying balance between growing and breeding was 53.7 hm 2 in the hoggery. [Conclusion] The research provided a scientific method for balance between growing and breeding. 展开更多
关键词 Breeding farm Farmland load n balance balance between growing and breeding
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Ammonia volatilization losses and ^(15)N balance from urea applied to rice on a paddy soil 被引量:10
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作者 FAN Xiao-hui SONG Yong-sheng +2 位作者 LIN De-xi YANG Lin-zhang LUO Jia-fa 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2006年第2期299-303,共5页
Ammonia volatilization loss and ^15N balance were studied in a rice field at three different stages after urea application in Taihu Lake area with a micrometeorological technique. Factors such as climate and the NH4^... Ammonia volatilization loss and ^15N balance were studied in a rice field at three different stages after urea application in Taihu Lake area with a micrometeorological technique. Factors such as climate and the NH4^+-N concentration in the field floodwater affecting ammonia loss were also investigated. Results show that the ammonia loss by volatilization accounted for 18.6%-38.7% of urea applied at different stages, the greatest loss took place when urea was applied at the tillering stage, the smallest at the ear bearing stage, and the intermediate loss at the basal stage. The greatest loss took place within 7 d following the fertilizer application. Ammonia volatilization losses at three fertilization stages were significantly correlated with the ammonium concentration in the field floodwater after the fertilizer was applied. ^15N balance experiment indicated that the use efficiency of urea by rice plants ranged between 24.4% and 28.1%. At the early stage of rice growth, the fertilizer nitrogen use efficiency was rather low, only about 12%. The total amount of nitrogen lost from different fertilization stages in the rice field was 44.1%-54.4%, and the ammonia volatilization loss was 25.4%-33.3%. Reducing ammonia loss is an important treatment for improving N use efficiency. 展开更多
关键词 ammonia volatilization UREA ^15n balance RICE influence factors Taihu region
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酸化对水稻-土壤系统氮分配和N_(2)O排放的影响
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作者 张宗祥 李华玮 +5 位作者 尚文鼎 曹传莉 孙梦雨 李笑笑 董召荣 宋贺 《农业环境科学学报》 CAS CSCD 北大核心 2024年第2期452-461,共10页
为研究土壤酸化对水稻-土壤系统氮转化、分配和氮损失的影响,以水稻-土壤系统为研究对象,设置中性(pH 7,CK)、弱酸(pH 6,T1)、中强酸(pH 5,T2)和强酸(pH 4,T3)4个土壤递增酸度处理,比较了不同酸度下水稻产量、氮素积累量、氮代谢酶活性... 为研究土壤酸化对水稻-土壤系统氮转化、分配和氮损失的影响,以水稻-土壤系统为研究对象,设置中性(pH 7,CK)、弱酸(pH 6,T1)、中强酸(pH 5,T2)和强酸(pH 4,T3)4个土壤递增酸度处理,比较了不同酸度下水稻产量、氮素积累量、氮代谢酶活性、氮素利用效率、氮平衡和N_(2)O排放等指标的差异。结果表明,随着土壤酸度增加,水稻植株氮素积累、利用效率和产量呈现先增加后降低的趋势。相关性分析表明,拔节期氮素积累量与叶片中硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)和谷氨酸脱氢酶(GDH)以及茎秆中GS和GOGAT活性呈显著正相关;开花期氮素积累量与穗中的NR、GS、GOGAT和GDH活性呈显著正相关。T1、T2和T3处理N_(2)O累积排放量与CK处理相比分别降低20.3%、58.0%和76.7%;单位产量下的N_(2)O排放量呈现递减的趋势。氮平衡分析表明,相比于CK处理,T2和T3处理氮素表观损失分别降低15.8%和21.1%,水稻氮吸收量分别降低1.5%和15.3%,土壤无机氮残留量分别增加41.2%和88.2%,氮素盈余率分别提高2.2个和7.1个百分点。土壤酸化至中强酸和强酸时,会分别通过抑制水稻拔节期茎叶和开花期穗部的氮代谢过程降低氮素积累量、利用效率和产量。土壤酸化会降低稻田N_(2)O累积排放量,同时也会降低单位产量N_(2)O排放量。此外,中强酸和强酸度土壤还会通过降低水稻氮吸收量和增加播前土壤无机氮量,提高土壤无机氮残留量和氮素盈余率,增加环境风险。 展开更多
关键词 土壤酸化 水稻 氮素利用效率 产量 n_(2)O 土壤氮平衡
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Reconstructed annual glacier surface mass balance in theányêmaqên Mountains,Yellow River source,based on snow line altitude 被引量:1
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作者 LI Kai-ji CAO Bo +2 位作者 GUAN Wei-jin PAN Bao-tian SHANGGUAN Dong-hui 《Journal of Mountain Science》 SCIE CSCD 2022年第4期1070-1081,共12页
Annual mass balance is an important factor that reflects glacier change and glacier meltwater resources.In this study,we analyzed the changes in glacier area,snow line altitude(SLA)and surface elevation in theány... Annual mass balance is an important factor that reflects glacier change and glacier meltwater resources.In this study,we analyzed the changes in glacier area,snow line altitude(SLA)and surface elevation in theányêmaqên Mountain region using multisource remote sensing data.Then,the annual mass balance of two glaciers was reconstructed by using SLA-mass-balance gradient method.The results showed that the glacier area in theányêmaqên Mountains decreased by 29.4 km2from 1985 to 2017.The average SLAs of the Halong Glacier and Yehelong Glacier were approximately 5290 m and 5188 m,respectively.The glacier mass balance for the two glaciers from 1990 to 2020 was-0.71 m w.e.a^(-1) and-0.63 m w.e.a^(-1),respectively.Our results indicate that SLA is an important indicator of glacier changes,and a long sequence of SLAs can more accurately reconstruct the glacier mass balance of the glacier.The mean annual glacial meltwater-fed streamflow is 1.45×10^(7)m^(3) and 1.12×10^(7)m^(3),respectively.Sensitivity analysis indicates that summer air temperature plays a leading role in regard to the influential climatic factors of glacial retreat in theányêmaqên Mountains.This highlights the potential of the methodology for application on reconstructing annual glacier surface mass balance at larger scales without direct measurements. 展开更多
关键词 Snow line altitude(SLA) Glacier annual mass balance reconstruction Glacier changes ányêmaqên Mountains
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冲击电弧作用下C_(4)F_(7)N/CO_(2)气体灭弧性能仿真分析 被引量:1
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作者 吴东 陈文贵 《电力工程技术》 北大核心 2024年第2期179-188,共10页
C_(4)F_(7)N/CO_(2)混合气体是目前最有潜力替代SF 6的气体之一。为了探讨C_(4)F_(7)N/CO_(2)混合气体的灭弧能力,文中根据电弧能量平衡理论,建立电弧能量平衡方程组,获取管道内部超压随时间的变化规律。同时,基于磁流体动力学模型,使用... C_(4)F_(7)N/CO_(2)混合气体是目前最有潜力替代SF 6的气体之一。为了探讨C_(4)F_(7)N/CO_(2)混合气体的灭弧能力,文中根据电弧能量平衡理论,建立电弧能量平衡方程组,获取管道内部超压随时间的变化规律。同时,基于磁流体动力学模型,使用COMSOL Multiphysics软件建立压爆气流防雷间隙灭弧结构的二维磁流体模型,在雷电流幅值为4 kA的条件下,对管道内不同比例C_(4)F_(7)N/CO_(2)混合气体在冲击电弧作用下的熄弧特性进行仿真分析。基于上述方法,结合电弧能量平衡理论,分析模型中电导率、速度以及压强的变化规律。与理论结果对比分析得出:同一工况条件下,20%C_(4)F_(7)N/80%CO_(2)的灭弧性能较优,其次为10%C_(4)F_(7)N/90%CO_(2)与5%C_(4)F_(7)N/95%CO_(2),并且熄弧时间符合气吹灭弧的要求。 展开更多
关键词 C_(4)F_(7)n/CO_(2)混合气体 灭弧性能 电弧能量平衡理论 磁流体动力学模型 冲击电弧 熄弧时间
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Effect on greenhouse gas balance of converting rice paddies to vegetable production
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作者 Lei Wu Xian Wu Ronggui Hu 《Acta Geochimica》 EI CAS CSCD 2017年第3期353-354,共2页
Rice paddies are increasingly being converted to vegetable production due to economic benefits related,in part,to changes in demand during recent decades.Here,we implemented a parallel field experiment to simultaneous... Rice paddies are increasingly being converted to vegetable production due to economic benefits related,in part,to changes in demand during recent decades.Here,we implemented a parallel field experiment to simultaneously measure annual emissions of CH_4and N_2O,and soil organic carbon(SOC)stock changes,in rice paddies(RP),rice paddy–converted conventional vegetable fields(CV),and rice paddy–converted greenhouse vegetable fields(GV).Changing from rice to vegetable production reduced CH_4emissions by nearly 100%,and also triggered substantial N_2O emissions.Furthermore,annual N_2O emissions from GV significantly exceeded those from CV due to lower soil p H and higher soil temperature.Marginal SOC losses occurred after one year of cultivation of RP,CV,and GV,contributing an important share(3.4%,32.2%,and 10.3%,respectively)of the overall global warming potential(GWP)balance.The decline in CH_4emissions outweighed the increased N_2O emissions and SOC losses in CV and GV,leading to a 13%–30%reduction in annual GWP as compared to RP.These results suggest that large-scale expansion of vegetable production at the expense of rice paddies is beneficial for mitigating climate change in terms of the overall GWP. 展开更多
关键词 Greenhouse gas balance Land management change CH4 n2O Soil organic carbon
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ON BALANCED n-ARY t-DESIGNS
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作者 Guo Li-ming ( Department of Mathematics, Yunnan Teachers’ University ) 《红河学院学报》 1990年第4期19-27,共9页
A t-(v,k,λ)design(X,B)is a set X of points,of cardinality v,and a collection B of k-subsets of X called blocks,with the property that every t-subset of X is contained in precisely λ blocks.A t-design is a t-(v,k,λ)... A t-(v,k,λ)design(X,B)is a set X of points,of cardinality v,and a collection B of k-subsets of X called blocks,with the property that every t-subset of X is contained in precisely λ blocks.A t-design is a t-(v,k,λ) design for some v,k,γ.In this paper,we give a generalization of t-design called balanced n-ary t-design,and obtain some properties of the new combinatorial structure. 展开更多
关键词 balanceD n-ary T-DESIGnS InCIDEnCE STRUCTURE
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Comparison of Urea-Derived N_2O Emission from Soil and Soil-Plant System 被引量:5
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作者 CHENLIJUN O.VANCLEEMPUT 《Pedosphere》 SCIE CAS CSCD 2000年第3期207-212,共6页
A pot experiment with a sandy loam soil and spring wheat as test crop was conducted to compare the N2O emission from soil system with plant cut off and from soil-plant system with plant kept. The results showed that a... A pot experiment with a sandy loam soil and spring wheat as test crop was conducted to compare the N2O emission from soil system with plant cut off and from soil-plant system with plant kept. The results showed that after urea fertilizer applied, the N2O emission from soil and soil-wheat system decreased exponentially with time, and its total amount was 0.34%~0.63% and 0.33%~0.58% of applied urea-N respectively, no significant difference being found between these two systems. The N2O emission had a very significant negative relationship (P = 0.01) with the biomass of wheat plant. A combined application of urease inhibitor hydroquinone and nitrification inhibitor dicyandiamide could reduce the N2O emission by 50%~83% and 46%~74%, respectivelyl from soil and soil-wheat system. The N2O was mainly produced and emitted from soil, and the soil biochemical regulation, i.e., applying related inhibitors into soil could effectively diminish the urea derived N2O emission. 展开更多
关键词 n2O emission SOIL soil-plant system URE
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网箱养殖N、P物质平衡研究——以广东省哑铃湾网箱养殖研究为例 被引量:24
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作者 舒廷飞 温琰茂 +3 位作者 陆雍森 韦献革 周劲风 贾后磊 《环境科学学报》 CAS CSCD 北大核心 2004年第6期1046-1052,共7页
通过借鉴封闭系统水产养殖物质平衡的观测思路,把网箱当作黑箱,对广东省哑铃湾一个典型鱼排网箱养殖的物质平衡进行了观测和计算,建立了网箱养殖N、P物质平衡方程.结果表明,网箱养殖N、P物质的利用率比基塘、虾池等封闭系统要低得多,而... 通过借鉴封闭系统水产养殖物质平衡的观测思路,把网箱当作黑箱,对广东省哑铃湾一个典型鱼排网箱养殖的物质平衡进行了观测和计算,建立了网箱养殖N、P物质平衡方程.结果表明,网箱养殖N、P物质的利用率比基塘、虾池等封闭系统要低得多,而且网箱养殖N、P的输入主要是投饵造成的,而输入的N、P物质,在水环境中发生一系列的迁移、转化,除了10%左右被利用收获外,其余的大部分被水动力带走,污染临近水域,还有一部分则沉积在底泥中,形成内源污染. 展开更多
关键词 网箱养殖 虾池 收获 投饵 水产养殖 水域 利用率 P物质 左右 污染
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Effect of Transplanting Density on Rice Yield,Nitrogen Uptake and ^(15)N-fertilizer Fate 被引量:5
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作者 樊红柱 张鸿 +2 位作者 冯文强 张冀 王昌桃 《Agricultural Science & Technology》 CAS 2012年第5期1037-1039,1054,共4页
[Objective] The aim of this study was investigated the rice yield, nitrogen uptake and ^15-fertilizer fate at different transplanting density to provide scientific ba- sis for improving the yield of rice and applying ... [Objective] The aim of this study was investigated the rice yield, nitrogen uptake and ^15-fertilizer fate at different transplanting density to provide scientific ba- sis for improving the yield of rice and applying reasonably fertilizer. [Method] A field experiment was carried out to study the effect of different transplanting density on rice yield, nitrogen (N) absorption, sources of N uptake by rice and the N balance in the plant-soil systems by using ^15-labelled urea. [Result] There were no significant differences in rice yields and total N uptakes by rice between treatments 30 cm × 30 cm and 40 cm × 40 cm, but the yield of rice and total N absorption in the two treatments were remarkably higher than those in 50 cm × 50 cm treatment. The amounts of total N uptake by rice were in the range of 112.3-162.7 kg/hm2 in the three transplanting densities. The result showed that about 1/3 of the total N uptake by rice was supplied by application fertilizer and the other 2/3 was obtained from the soil N pool. The ^15N-labelled urea absorbed by rice, residual in soil and lost accounted for 16.3%-26.1%, 17.0%-20.9% and 53.0%-66.7% of the total fertilizer, respectively. A great deal of ^15N-labelled urea was lost during the rice growing season. [Conclusion] Considering the rice yield and environmental protection, the transplanting density of 30 cm×30 cm was recommended in the hilly area of Sichuan basin in the southwest China. 展开更多
关键词 Rice yield nitrogen uptake and balance ^15n-labeled urea ^15n fate Transplanting density
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滴灌施肥对冬小麦农田土壤NO_3^--N分布、累积及氮素平衡的影响 被引量:16
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作者 陈静 王迎春 +3 位作者 李虎 王立刚 邱建军 肖碧林 《植物营养与肥料学报》 CAS CSCD 北大核心 2015年第4期927-935,共9页
【目的】黄淮海平原高产麦田水肥资源的大量投入带来了水肥利用率低、氮素损失量大等一系列问题,本文研究了滴灌施肥对黄淮海平原冬小麦大田氮素利用和损失的影响,以期为小麦高产高效施肥提供新的技术手段。【方法】以尿素、NH4H2PO4和... 【目的】黄淮海平原高产麦田水肥资源的大量投入带来了水肥利用率低、氮素损失量大等一系列问题,本文研究了滴灌施肥对黄淮海平原冬小麦大田氮素利用和损失的影响,以期为小麦高产高效施肥提供新的技术手段。【方法】以尿素、NH4H2PO4和KCl混合的水溶性肥料为材料,在山东桓台进行冬小麦主要生育期测墒补灌并随水施肥的田间试验,设置4个施氮量处理,即N0(不施肥)、N1(94.5 kg/hm2)、N2(189 kg/hm2)和N3(270 kg/hm2),分析了大田土壤NO-3-N空间分布、剖面累积及氮素的平衡。【结果】1)滴灌施肥24 h后,随施氮量的增加,在滴头周围水平方向上土壤NO-3-N从在湿润土体边缘聚集逐渐变化为在滴头下方聚集,当施氮量为189 kg/hm2时,滴灌施肥后滴头下方和湿润土体边缘的NO-3-N含量差异不显著,在滴头周围水平方向上均匀性最好;NO-3-N在滴头下方土壤内随水运移深度主要在60 cm以上,滴灌施肥后滴头下方垂直方向上NO-3-N没有在湿润体边缘聚集。2)冬小麦收获后,0—100 cm土壤剖面NO-3-N累积量随施氮量的增加而逐渐增加,且施氮量超过N 189kg/hm2后,土壤剖面NO-3-N累积量的增加幅度加大,0—40 cm土层的NO-3-N增加量显著高于其他土层,N0、N1、N2和N3处理0—40 cm土层NO-3-N累积量所占比例分别为66%、72%、72%和71%。3)随着施氮量的增加,冬小麦吸氮量和籽粒产量先增加后下降,而0—100 cm土层氮素残留量、表观损失量不断增加,滴灌施肥条件下氮素表观损失量较低,N1、N2和N3的表观损失率分别为20%、17%和16%。【结论】滴灌施肥措施下,合理的灌溉量可以调节滴灌施肥后硝态氮主要向下运移至作物根区范围,集中在作物根系最密集的0—40 cm范围内,肥液浓度对硝态氮运移深度影响不大。施入适宜量氮肥有利于提高滴头下方湿润体内水平方向上NO-3-N分布的均匀度,从而促进作物对氮素的吸收。施氮量为189 kg/hm2的N2处理获得了最高的籽粒产量和氮肥利用效率,播前和收获后根区土壤NO-3-N累积量基本达到平衡,是试验筛选出的最佳滴灌施氮模式。 展开更多
关键词 冬小麦 滴灌施肥 nO3^--n 空间分布 氮素平衡
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华北马铃薯连作土壤微生物残体氮对氮肥用量的响应
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作者 吕慧丹 何萍 赵士诚 《植物营养与肥料学报》 CAS CSCD 北大核心 2024年第10期2024-2031,共8页
【目的】微生物残体氮作为一种稳定而重要的土壤氮组分,在维持土壤肥力方面发挥着重要作用。氮肥施用量影响土壤微生物残体氮的转化和积累,研究微生物残体氮对不同施氮量的响应对于优化施氮管理以提高土壤肥力至关重要。【方法】马铃薯... 【目的】微生物残体氮作为一种稳定而重要的土壤氮组分,在维持土壤肥力方面发挥着重要作用。氮肥施用量影响土壤微生物残体氮的转化和积累,研究微生物残体氮对不同施氮量的响应对于优化施氮管理以提高土壤肥力至关重要。【方法】马铃薯氮肥管理试验始于2017年,在内蒙古自治区武川旱作试验站进行。种植模式为马铃薯连作,试验设置4个处理:NE [肥料用量用NE (Nutrient Expert,养分专家系统)推荐确定]、NE-N(不施氮肥)、NE-1/2N (氮肥用量较NE处理减少1/2)和NE+1/2N (氮肥用量较NE处理增加1/2)。于2023年马铃薯收获期,采集0—20和20—40 cm土层土壤样品,测定土壤矿质氮和微生物残体氮含量,分析马铃薯连作下不同氮肥用量对土壤矿质氮和微生物残体氮的影响。【结果】氮肥施用处理较NE-N处理增加了土壤全氮(TN)和NO-_(3)^(-)-N含量。在20—40 cm土层,土壤NO_(3)^(-)-N和NH_(4)^(+)-N随着施氮量的增加而增加;但在0—20 cm土层,土壤TN、NO_(3)^(-)-N和NH_(4)^(+)-N在3个施氮处理之间没有显著差异。与NE处理相比,NE-N和NE-1/2N处理降低了土壤细菌、真菌和微生物残体氮含量,而NE+1/2N处理并没有增加这些残体氮含量。在所有处理中,真菌残体氮与细菌残体氮的比值随着施氮量的增加而逐渐降低,并且20—40 cm土层中的比值高于0—20 cm土层。在所有处理中,微生物残体氮与土壤全氮的比值达64.2%~73.2%,不同施氮量对0—20 cm深度的比值没有影响;然而,NE-N、NE-1/2N、NE+1/2N处理20—40 cm土层微生物残体氮与土壤全氮的比值较NE处理降低了4.1%~13.2%。NE处理维持了较好的土壤氮平衡,而NE+1/2N处理导致了极大的土壤氮盈余。【结论】在内蒙古马铃薯连作体系,土壤微生物残体氮随氮肥用量逐步增加,在NE推荐施氮量下获得了较高的微生物残体氮积累。因此,基于NE系统推荐施肥能维持土壤肥力和氮素平衡。 展开更多
关键词 马铃薯 土壤矿质氮 微生物残体氮 田间氮平衡 养分专家系统
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^(15)N尿素在兔体内消化吸收及利用机理研究 Ⅰ.兔对^(15)N尿素利用的氮平衡状况及形态分配 被引量:11
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作者 高家骅 周维仁 +3 位作者 章云 于亚君 陈明 黄玲 《江苏农业学报》 CSCD 北大核心 1998年第4期223-227,共5页
应用稳定同位素15N尿素示踪技术,经兔消化代谢试验,研究尿素氮平衡状况,测定其消化率和利用系数,并对在兔体内形成蛋白质沉积及其它含氮化合物形态与分配进行了讨论,肯定了尿素氮作为补充兔日粮中粗蛋白营养不足的价值。研究发... 应用稳定同位素15N尿素示踪技术,经兔消化代谢试验,研究尿素氮平衡状况,测定其消化率和利用系数,并对在兔体内形成蛋白质沉积及其它含氮化合物形态与分配进行了讨论,肯定了尿素氮作为补充兔日粮中粗蛋白营养不足的价值。研究发现,15N尿素在胃和小肠内容物中,具有与盲肠中相似的由微生物转化合成极易被兔消化利用的游离氨基酸15N和蛋白质15N等化合物的功能,从而促进了兔对日粮尿素的消化吸收和利用。 展开更多
关键词 饲料添加剂 尿素 氮平衡 消化 吸收
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不同耕作处理下大豆生物固N能力及对系统N素的贡献 被引量:4
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作者 谢田玲 沈禹颖 +2 位作者 高崇岳 南志标 Murray Unkovich 《生态学报》 CAS CSCD 北大核心 2006年第6期1772-1780,共9页
2002年至2003年在黄土高原研究了4个耕作处理,传统耕作(t)、传统耕作+秸秆覆盖(ts)、免耕(nt)和免耕+秸秆覆盖(nts)下大豆的生物固N百分率(%Ndfa)、固N数量及其对春玉米-冬小麦-夏大豆轮作系统中N素的贡献。结果表明,在tt、s、nt和nts... 2002年至2003年在黄土高原研究了4个耕作处理,传统耕作(t)、传统耕作+秸秆覆盖(ts)、免耕(nt)和免耕+秸秆覆盖(nts)下大豆的生物固N百分率(%Ndfa)、固N数量及其对春玉米-冬小麦-夏大豆轮作系统中N素的贡献。结果表明,在tt、s、nt和nts处理下2002年的生物固N百分率为17.6%、34.3%、22.4%和19.3%,2003年则为58.5%、62.4%、54.9%和43.8%,其中2003年的生物固N百分率比2002年分别高出69.9%、45.0%、59.3%和56.1%,固N数量高出56.2%、33.8%、49.5%和43.1%。大豆生物固N百分率、生物固N数量与生物量呈正相关关系,在ts处理下显著相关。土壤NO3-N含量和大豆固N数量呈负相关,大豆植株吸N量占土壤NO3-N的百分比在2002年为:t(88.1)>ts(84.6)>nts(78.7)>nt(63.6),2003年为:t(115.5)>ts(104.2)>nts(99.8)>nt(95.8)。2002年大豆对该轮作系统的N素贡献分别为6.6(t)、11.6(ts)6、.5(nt)和6.1(nts)kg/hm2,生物固N量占总N输入量的百分比为14.6(t)、21.5(ts)、14.9(nt)和12.9(nts);2003年大豆对系统的N素贡献分别为14.9(t)1、7.6(ts)、12.9(nt)和10.7(nts)kg/hm2,生物固N量占总N输入的百分比为63.2%(t)、58.5%(nt)、47.7%(ts)和39.9%(nts)。年际变异造成了大豆生物固N的年际差异,秸杆覆盖+耕作因改善水分状况,而促进了大豆的生物固N作用。 展开更多
关键词 15n自然丰度技术 生物固n n素贡献 n平衡 n亏缺 大豆
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N·K营养与N·K平衡对烤烟野火病发生的影响 被引量:2
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作者 董艳 董坤 +2 位作者 范茂攀 赵平 林克惠 《安徽农业科学》 CAS 北大核心 2007年第2期454-455,共2页
研究了云南中部地区烤烟中部叶片旺长后期(移栽后70~75d)N、K营养及N、K平衡对田间烤烟野火病发生的影响。结果表明:N含量高时(N>4%),病害发生严重,但发病严重程度取决于K的含量,K素过高和过低都增加了烤烟的感病率;K含量过低(K<... 研究了云南中部地区烤烟中部叶片旺长后期(移栽后70~75d)N、K营养及N、K平衡对田间烤烟野火病发生的影响。结果表明:N含量高时(N>4%),病害发生严重,但发病严重程度取决于K的含量,K素过高和过低都增加了烤烟的感病率;K含量过低(K<2%),会降低烤烟的抗病性;烟叶N/K比失调,会影响烟株的生长发育,使烤烟对病害的抵抗能力降低。 展开更多
关键词 烤烟 n、K营养 n、K平衡 野火病
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烤烟烟叶中N、K营养及N、K平衡的初步研究 被引量:4
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作者 祖艳群 林克惠 《西北植物学报》 CAS CSCD 2000年第5期831-834,共4页
研究了滇中地区烤烟中部叶片旺长期 (移栽后 60~ 65d) N、K营养及 N、K平衡。结果表明 :( 1 )烟叶一般 N含量为 2 .5%~ 4% ,K含量为 1 %~ 3% ,N/K比为 2 .5~ 3.5。 ( 2 )烟叶 N含量 >4% ,就有 N过剩的症状产生。 ( 3)烟叶 N含量 ... 研究了滇中地区烤烟中部叶片旺长期 (移栽后 60~ 65d) N、K营养及 N、K平衡。结果表明 :( 1 )烟叶一般 N含量为 2 .5%~ 4% ,K含量为 1 %~ 3% ,N/K比为 2 .5~ 3.5。 ( 2 )烟叶 N含量 >4% ,就有 N过剩的症状产生。 ( 3)烟叶 N含量 <2 .5% ,K含量 <1 % ,就表现出N、K缺乏症状。 ( 4 )烟叶 N/K比失调 ,过高或过低 ,都会影响烟株正常生长。 展开更多
关键词 烟叶 氮营养 钾营养 氮钾平衡 烤烟
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^(15)N标记羊粪和稻草还田氮素的转化和效应的研究 被引量:14
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作者 廖先苓 周卫军 何电源 《土壤学报》 CAS CSCD 北大核心 1995年第3期292-299,共8页
本工作通过田间微区试验,研究了^(15)N标记羊粪和稻草单独施用或分别与尿素配合施用作为水稻基肥时,肥料氮的命运及其对水稻产量的影响。结果表明,羊粪单施或与化肥N配合施用时,稻谷回收的羊粪N分别为7.9%和9.2%,... 本工作通过田间微区试验,研究了^(15)N标记羊粪和稻草单独施用或分别与尿素配合施用作为水稻基肥时,肥料氮的命运及其对水稻产量的影响。结果表明,羊粪单施或与化肥N配合施用时,稻谷回收的羊粪N分别为7.9%和9.2%,相当于饲料稻草N的2.2%和2.6%,若将羊体中回收的饲料稻草N量(31.2%) ̄[6]计入,则羊体和稻谷共回收饲料稻草N分别为33.4%和33.7%,明显高于稻草直接还田时稻谷对稻草N的回收率(单施和与化肥配合施用时分别为9.9%和14.5%)。稻草喂羊,再以其粪尿还田,其经济效益也明显高于稻草直接还田。 展开更多
关键词 ^(15)n标记羊粪 稻草还田 n素平衡账
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侧链衍生季铵盐型氯胺的合成及抗菌应用
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作者 李令东 张颂伟 +3 位作者 张维伦 刘鹏飞 于江际鸣 周豪 《应用化学》 CAS CSCD 北大核心 2024年第7期966-975,共10页
以5,5-二甲基海因(DMH)为原料,设计合成了一系列侧链衍生的季铵盐型氯胺抗菌剂(10-14),表征了前体和氯胺结构。以大肠杆菌(E.coli)和金黄葡萄球菌(S.aureus)为模式菌株,以三甲基季铵盐氯胺1为对照,初步测试了氯胺10-14的抗菌活性。结果... 以5,5-二甲基海因(DMH)为原料,设计合成了一系列侧链衍生的季铵盐型氯胺抗菌剂(10-14),表征了前体和氯胺结构。以大肠杆菌(E.coli)和金黄葡萄球菌(S.aureus)为模式菌株,以三甲基季铵盐氯胺1为对照,初步测试了氯胺10-14的抗菌活性。结果表明,氯胺10-13抗菌能力随侧链变长先增强后减弱,其中三丁基季铵盐氯胺12对S.aureus和E.coli的杀灭对数(KL)值分别为1.07±0.09和6.49,表现出这一系列中相对更优的抗菌活性,这可能是12达到了分子触杀所需的最佳亲疏水平衡状态,与菌体细胞膜作用更强所致。此外,携羟乙基侧链氯胺14实现了对S.aureus和E.coli全杀,展现了10-14中最出色的抗菌性能,这可能和氯胺分子更易穿透菌体细胞膜有关。本工作制备的一系列高活性季铵盐氯胺抗菌剂,为更高效离子型氯胺抗菌剂的设计研发提供了参考借鉴。 展开更多
关键词 季铵盐型氯胺 多步合成 抗菌活性 亲疏水平衡 侧链衍生物
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GaInP/GaAs/InGaAs倒装三结太阳电池设计与优化 被引量:3
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作者 马大燕 陈诺夫 +3 位作者 付蕊 刘虎 白一鸣 陈吉堃 《太阳能学报》 EI CAS CSCD 北大核心 2018年第2期550-557,共8页
为获得带隙组合对太阳光谱有效的分割利用,基于细致平衡原理,结合p-n结形成机理,应用Matlab语言对GaInP(1.90eV)/GaAs/InGaAs倒装结构电池体系底电池带隙和各子电池厚度进行模拟优化。结果表明底电池带隙为1.0eV时,光电转换... 为获得带隙组合对太阳光谱有效的分割利用,基于细致平衡原理,结合p-n结形成机理,应用Matlab语言对GaInP(1.90eV)/GaAs/InGaAs倒装结构电池体系底电池带隙和各子电池厚度进行模拟优化。结果表明底电池带隙为1.0eV时,光电转换效率最高。通过对GaInP(1.90eV)/GaAs(1.42eV)/InGaAs(1.0eV)倒装结构三结太阳电池各结厚度进行优化,综合考虑材料成本及生产技术等闪素,最佳厚度组合为1.35、2.83和3.19μm时,光电转换效率为44.4%,仅比最高转换效率低0.3%。 展开更多
关键词 太阳电池 细致平衡 P-n 倒装结构(IMM)
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