Results 21 to 30 of about 7,054 (156)

稻田水资源利用效用的灌排模式响应

open access: yesShuitu Baochi Xuebao, 2022
为全面揭示稻田水资源利用效用,在观测浅水勤灌(FI)、浅湿灌溉(WI)、控制灌溉(CI)和蓄水控灌(RI)处理试验小区田间水量平衡的基础上,建立了灌溉水、降水消耗通量区分方法及其利用效用评价指标体系,分析了水资源利用效用的灌排模式响应。结果表明:田间灌溉水和降水消耗量、有效利用率及水分生产力均受灌排模式的影响;2017-2018年各处理水资源消耗量为695.9~999.1 mm,其中CI处理水资源消耗量最低,并且消耗结构更加合理。CI处理的灌溉水生产力(IWP,5.392 kg/m3)、降水生产力 ...
李玥瑶   +3 more
doaj   +2 more sources

Effects of Winter Irrigation on Soil Water-heat-salt Migration and Crop Growth During Freezing-Thawing Period in Qingtongxia Irrigation District of Ningxia [PDF]

open access: yes, 2023
[Objective] The effects of winter irrigation on soil water-heat-salt migration and crop growth during the freezing-thawing period were analyzed in order to provide a scientific basis for controlling soil salinization, and to ensure food security ...
Han Yuping   +4 more
core   +1 more source

Comparative Evaluation of Chemical and Physical Expansive Agents in Cemented Paste Backfill: Expansion Behavior, Mechanical Response, and Microstructural Mechanisms

open access: yesRare Metals, Volume 45, Issue 4, April 2026.
ABSTRACT This study presents an assessment of four representative expansive additives—calcium sulphoaluminate–calcium oxide, magnesium oxide, sodium lauryl sulfate, and sodium abietate—and their effects on the expansion behavior, mechanical development, and microstructural characteristics of cemented paste backfill (CPB).
Lijie Guo   +5 more
wiley   +1 more source

Testing GLEAMS for Nitrate Leaching Modeling in an Agricultural Catchment of Southeast China [PDF]

open access: yes, 2007
利用我国东南亚热带地区农业小流域不同土地利用方式的硝氮渗漏淋失实测数据检验了GLEAMS(Groundwater Loading Effects of Agricultural Management Systems)模型在该地区的适用性。通过现场试验和实地调查并结合模型手册,获取模型所需的水文和营养盐参数,参考模型参数的敏感性分析结果对模型进行调试。结果表明模型对水稻田除外的其它土地利用方式的硝氮渗漏淋失模拟效果较好。水稻田渗漏模拟效果差的主要原因在于模型的水分平衡方程不能反应水稻田长期淹水的实际情况 ...
徐玉裕   +3 more
core  

Supply and Demand of Multi-scale Ecosystem Services and Their Influencing Factors in Hu’nan Province [PDF]

open access: yes, 2023
[Objective] The distribution pattern of ecosystem service supply and demand and their main driving factors were analyzed in order to provide a scientific reference for regional ecological protection practices and ecological environmental improvement ...
Liu Chang   +5 more
core   +1 more source

Functional Stability Despite Taxonomic Changes in Mixed‐Species Foraging Flock Participants Along an Elevational Gradient in Knuckles Montane Reserve, Sri Lanka 斯里兰卡纳克斯山地保护区 (Knuckles Montane Reserve) 海拔梯度上混合物种觅食群参与者的功能稳定性与分类变化

open access: yesIntegrative Conservation, Volume 5, Issue 1, Page 59-73, March 2026.
This research reveals the functional stability of mixed species foraging flocks (MSF) and their foraging height change with different taxonomic differences along the elevational gradient at Knuckles Montane Reserve, Sri Lanka. This offers new insights into how MSFs sustain with the elevational gradients supporting the altitudinal shifting species ...
Vimukthi. R. Gunasekeara   +3 more
wiley   +1 more source

Assessing Nitrate Leaching With GLEAMS Model in an Agricultural Small Catchment in Southeast China. [PDF]

open access: yes, 2007
应用GLEAMS模型估算我国东南亚热带地区农业小流域硝态氮的渗漏淋失。在五川流域8种不同土地利用方式的农田中埋设渗漏监测装置,每月采集水样分析硝态氮含量。用2002年4—12月作物生长季节的实测数据进行模型校验的结果表明,模型对水稻田除外的其他土地利用方式下硝态氮渗漏淋失模拟效果较好。五川流域2002年硝态氮淋失模拟计算结果表明,不同土地利用方式下硝态氮淋失时空差异显著,全年渗漏量(以氮计)为4.6438.39 kg.hm-2,流域面积加权平均为29.99 kg.hm-2。甘蔗地 ...
曹文志, 王吉苹
core  

Life Stage‐Specific Genetic Diversity and Landscape Characteristics Collectively Influence Genetic Recovery in Pometia pinnata Population 生活史阶段特异的遗传多样性与景观特征对番龙眼种群遗传恢复的协同影响

open access: yesIntegrative Conservation, Volume 5, Issue 1, Page 137-149, March 2026.
Pometia pinnata demonstrated life‐stage‐specific genetic responses to landscape features, with asymmetric gene flow patterns and population recovery following historical bottlenecks, revealing complex topographic and demographic influences on forest genetic structure.
Madhuparna Chatterjee   +5 more
wiley   +1 more source

重庆市化肥使用与残留的时空分异特征研究

open access: yesShuitu Baochi Xuebao, 2004
通过采集39个样本,调查研究了重庆市1998~2002年化肥使用与残留的分布特征。重庆市化肥全年使用水平为317.08 km/hm~2,高于全国平均水平。都市发达圈水平最高达758.24 km/hm~2,是渝西走廊的2倍。按施肥量水平则分为高施肥量区、中施肥量区、低施肥量区。施肥量水平与粮食产出、种植业经济产出呈明显的负相关性,施肥量越高,其投入效率越低,呈现出明显的报酬递减规律。化肥当季使用水平(x)与粮食产量(y)之间的关系为一抛物线方程。化肥平均利用率为35.72%,其中高施肥量区域最低,只有32.
欧阳柬 陈玉成 严素定
doaj  

膜下滴灌条件下绿洲棉田土壤水分运动数值模拟 [PDF]

open access: yes, 2007
应用非饱和土壤水运动理论,建立膜下滴灌条件下土壤水分运动二维数值模拟模型,研究了田间层状土壤在膜下滴灌条件下土壤水分运动特征。应用不同小区不同灌水处理的实测值与模拟值进行对比,同时对模型做了精度分析,结果表明符合精度要求,这说明所建立的模型能客观地反映实际土壤条件下的水分运动情况。研究结果表明:土壤剖面30~40 cm粘土层使土壤水分运动具有很大的差异,0~30 cm变化明显,而40 cm以下土壤水分运动的变化较小。膜下滴灌应该采取灌水量小 ...
串志强, 方怡向, 盛钰, 赵成义
core  

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