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Difference between Responses of Potato Plant Height to Corrected FAO-56-recommended Crop Coefficient and Measured Crop Coefficient 被引量:4
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作者 陈秋帆 代兴梅 +2 位作者 陈劲松 颜雄 彭尔瑞 《Agricultural Science & Technology》 CAS 2016年第3期551-554,共4页
This study was conducted to establish a simple convenient method for calculating crop coefficient, and provide a certain basis for the research of the empirical formula for calculating crop coefficient with plant heig... This study was conducted to establish a simple convenient method for calculating crop coefficient, and provide a certain basis for the research of the empirical formula for calculating crop coefficient with plant height which could be measured conveniently with regional differences, especially for the establishment of accurate irrigation schedule of potato in Yunnan. By the field experiment on potato under the condition of drip irrigation, it was found that the models of plant height with corrected FAO-56-recommended K and measured K were a quartic polynomial and a cubic polynomial, respectively, and the polynomial of potato plant height with measured crop coefficient was simpler with higher degree of fitting; and the differences between the period with the highest change rate of potato plant height and the periods with the greatest FAO-56-recommended K and measured K exhibited a differences of 3 d. In conclusion: In the future study of simple or empirical formula calculation of crop coefficient, plant height should be considered as a main dependent variable in that the calculation result would be closer to the measured crop coefficient with the problem of regional difference existing in the FAO method solved and the formula might be simpler; and the irrigation time of potato should be 3 d earlier than the irrigation time determined according to the corrected FAO-56-recommended crop coefficient, especially in the key water requirement stages of potato. 展开更多
关键词 POTATO Plant height crop coefficient Field planting
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覆土浅埋滴灌玉米分阶段亏水条件下AquaCrop与Dual Crop Coefficient模型精度对比研究 被引量:2
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作者 戚迎龙 赵举 +3 位作者 宁小莉 李彬 李敏 史海滨 《东北农业大学学报》 CAS CSCD 北大核心 2023年第6期64-77,共14页
近年来,西辽河流域地下水超采问题日益突出,改进灌溉技术降低农业用水可有效解决这一问题,但该技术缺乏科学的水分管理方法及适宜的理论模型。基于单阶段及多阶段亏水情形试验,对比同类农田水分模型精度,优选阶段性亏水管理辅助模型。... 近年来,西辽河流域地下水超采问题日益突出,改进灌溉技术降低农业用水可有效解决这一问题,但该技术缺乏科学的水分管理方法及适宜的理论模型。基于单阶段及多阶段亏水情形试验,对比同类农田水分模型精度,优选阶段性亏水管理辅助模型。研究设置7个玉米分阶段亏水调控处理,于2018、2019年进行田间小区试验,取得2个同类模型的本地化参数并比较其模拟精度。结果表明,AquaCrop和双作物系数模型可相近表达玉米冠层发育到最大而未开始衰减期间土壤水分的消耗过程,而对快速生长期与后期1m土层贮水量的模拟差异大。AquaCrop模型在土壤贮水量偏低时高估其实测值,其他情形正负偏差分布相对均匀,双作物系数模型多数情形低估其实测值。AquaCrop模型描述玉米各阶段蒸散量因亏水情形而变化能力优于双作物系数模型。AquaCrop模型和双作物系数模型的标准均方根误差平均值在模拟1 m土层贮水量时分别为4.494%~8.443%、6.017%~8.626%,在模拟蒸散量时分别为8.158%~9.510%、5.980%~15.022%。综合来看,AquaCrop模型表现更好,推荐作为适宜西辽河流域覆土浅埋滴灌玉米水分管理模型。研究可为该区域覆土浅埋滴灌种植玉米选出适宜的水分管理模型,理解新技术条件下玉米分阶段亏水调控机制及田间灌溉管理优化提供参考。 展开更多
关键词 模型精度 Aquacrop模型 双作物系数模型 覆土浅埋滴灌 玉米分阶段亏水
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Determining Crop and Pan Coefficients for Cauliflower and Red Cabbage Crops Under Cool Season Semiarid Climatic Conditions 被引量:7
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作者 Ustun Sahin Yasemin Kuslu +1 位作者 Talip Tunc Fatih Mehmet Kiziloglu 《Agricultural Sciences in China》 CSCD 2009年第2期167-171,共5页
The aim of this study was to estimate the evapotranspiration of cauliflower and red cabbage crops grown under cool season semiarid climatic conditions from Class A pan evaporation. Actual evapotranspiration (ETc) of... The aim of this study was to estimate the evapotranspiration of cauliflower and red cabbage crops grown under cool season semiarid climatic conditions from Class A pan evaporation. Actual evapotranspiration (ETc) of cauliflower and red cabbage crops was calculated according to the water balance approach. Reference evapotranspiration (ETo) was calculated with FAO Penman-Monteith equation. Pan evaporation (Epan) was measured by using Class A pan. Seasonal ETc was determined as 475 mm for cauliflower and 556 nun for red cabbage. Seasonal pan coefficient (kp=ETo/Epan) was determined as 0.82, and the seasonal crop coefficient (kc=ETc/ETo) was determined as 0.84 for cauliflower and 0.83 for red cabbage. So the evapotranspiration of cauliflower and red cabbage crops was estimated as 70% Class A pan evaporation. 展开更多
关键词 crop coefficient kc EVAPOTRANSPIRATION pan coefficient (kp)
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Evapotranspiration, Yield and Crop Coefficient of Irrigated Maize Under Straw Mulch 被引量:12
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作者 ZHANG Xi-Ying CHEN Su-Ying PEI Dong LIU Meng-Yu SUN Hong-Yong 《Pedosphere》 SCIE CAS CSCD 2005年第5期576-584,共9页
Maize (Zea mays L.), a staple crop grown from June to September during the rainy season on the North China Plain,is usually inter-planted in winter wheat (Triticum aestivum L.) fields about one week before harvesting ... Maize (Zea mays L.), a staple crop grown from June to September during the rainy season on the North China Plain,is usually inter-planted in winter wheat (Triticum aestivum L.) fields about one week before harvesting of the winterwheat. In order to improve irrigation efficiency in this region of serious water shortage, field studies in 1999 and 2001, twodry seasons with less than average seasonal rainfall, were conducted with up to five irrigation applications to determineevapotranspiration, calculate the crop coefficient, and optimize the irrigation schedule with maize under mulch, as well asto establish the effects of irrigation timing and the number of applications on grain yield and water use efficiency (WUE)of maize. Results showed that with grain production at about 8 000 kg ha-1 the total evapotranspiration and WUE ofirrigated maize under mulch were about 380-400 mm and 2.0-2.2 kg m-3, respectively. Also in 2001 WUE of maizewith mulch for the treatment with three irrigations was 11.8% better than that without mulch. In the 1999 and 2001seasons, maize yield significantly improved (P = 0.05) with four irrigation applications, however, further increases werenot significant. At the same time there were no significant differences for WUE with two to four irrigation applications.In the 2001 season mulch lead to a decrease of 50 mm in the total soil evaporation, and the maize crop coefficient undermulch varied between 0.3-1.3 with a seasonal average of 1.0. 展开更多
关键词 crop coefficient MAIZE MULCH water use efficiency
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Estimating Crop Coefficient in Intermittent Irrigation Paddy Fields Using Excel Solver
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作者 Chusnul ARIF Budi Indra SETIAWAN +3 位作者 Hanhan Ahmad SOFIYUDDIN Lolly Martina MARTIEF Masaru MIZOGUCHI Ryoichi DOI 《Rice science》 2012年第2期143-152,共10页
The current study proposes a novel method using Excel Solver to estimate, from limited data, crop coefficient (Kc) in paddy fields under intermittent irrigation (11). The proposed method was examined in a field ex... The current study proposes a novel method using Excel Solver to estimate, from limited data, crop coefficient (Kc) in paddy fields under intermittent irrigation (11). The proposed method was examined in a field experiment conducted at Karang Sari Village, Bekasi, West Java, Indonesia during the first rice season of 2007/2008 (December 2007 to April 2008) in the rainy season. As the control, continuous flooding irrigation (CF) was applied to the conventional rice cultivation fields. Based on the observed water storage, Excel Solver was used to estimate crop evapotranspiration. Estimated crop evapotranspiration was used to compute Kc value, then the average Kc values at each growth stage were compared with that for the CF treatment. The estimation method was evaluated by comparing estimated crop evapotranspiration and the crop evapotranspiration derived by the well established FAO procedure. Excel Solver estimated crop evapotranspiration accurately with R2 values higher than 0.81. Accordingly, more than 81% of the FAO crop evapotranspiration was described by the proposed method. Thus, Kc value could be well determined from those estimated crop evapotranspiration. Under the II treatment, the average Kc values were 0.70, 1.06, 1.24 and 1:22 for the initial, crop development, reproductive and late stages, respectively. These values were lower than those under the CF treatment for initial and crop development stages because of a minimal soil evaporation and intense dryness during these stages. However, average Kc values under the II treatment were higher than those under the CF treatment at the reproductive and late stages, indicating that the II treatment promoted more plant activity particularly for dry biomass production as indicated by a greater number of tillers per hill. 展开更多
关键词 crop coefficient EVAPOTRANSPIRATION intermittent irrigation Excel Solver water balance
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Water requirements and single and dual crop coefficients of sugarcane grown in a tropical region, Brazil
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作者 Vicente de P. R. da Silva Cícera J. R. Borges +3 位作者 Carlos H. A. Farias Vijay P. Singh Walker G. Albuquerque Bernardo Barbosa da Silva 《Agricultural Sciences》 2012年第2期274-286,共13页
A field experiment was conducted throughout 2009/2010 in a sugarcane field of a commercial distillery located on the coastal area of Paraiba state, Brazil. The objectives were to determine sugarcane water requirements... A field experiment was conducted throughout 2009/2010 in a sugarcane field of a commercial distillery located on the coastal area of Paraiba state, Brazil. The objectives were to determine sugarcane water requirements and to test the single and dual crop coefficients by comparing the calculated values of ET with measured ones. Crop evapotranspiration was determined by field water balance, reference evapotranspiration (ETo) by the Penman-Monteith approach, while single and dual crop coefficients were computed through the standard FAO-56 methodology. The experimental area was cultivated with irrigation applied weekly by a centre pivot system in addition to rainfall and the irrigation scheduling was based on 100% ETo. Three statistical tests, mean bias difference (MBD), normalized root mean square difference (NRMSD) and regression analysis, were used to evaluate the performance of single and dual crop coefficients. Results showed that there was a notable symmetry between ET measured and ET calculated by Kc dual. The ET values, calculated from Kc single, underestimated those obtained from soil water balance measurements by 36%. 展开更多
关键词 crop coefficient EVAPOTRANSPIRATION RAINFED RAINFALL Water Stress
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Spectral Crop Coefficient Approach for Estimating Daily Crop Water Use
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作者 Nithya Rajan Stephan J. Maas 《Advances in Remote Sensing》 2014年第3期197-207,共11页
While the amount of water used by a crop can be measured using lysimeters or eddy covariance systems, it is more common to estimate this quantity based on weather data and crop-related factors. Among these approaches,... While the amount of water used by a crop can be measured using lysimeters or eddy covariance systems, it is more common to estimate this quantity based on weather data and crop-related factors. Among these approaches, the standard crop coefficient method has gained widespread use. A limitation of the standard crop coefficient approach is that it applies to “standard conditions” that are invariant from field to field. In this article, we describe a method for estimating daily crop water use (CWU) that is specific to individual fields. This method, the “spectral crop coefficient” approach, utilizes a crop coefficient numerically equivalent to the crop ground cover observed in a field using remote sensing. This “spectral crop coefficient” Ksp is multiplied by potential evapotranspiration determined from standard weather observations to estimate CWU. We present results from a study involving three farmers' fields in the Texas High Plains in which CWU estimated using the Ksp approach is compared to observed values obtained from eddy covariance measurements. Statistical analysis of the results suggests that the Ksp approach can produce reasonably accurate estimates of daily CWU under a variety of irrigation strategies from fully irrigated to dryland. These results suggest that the Ksp?approach could be effectively used in applications such as operational irrigation scheduling, where its field-specific nature could minimize over-irrigation and support water conservation. 展开更多
关键词 crop coefficient EVAPOTRANSPIRATION Water Use Ground COVER Remote Sensing
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Determination of Upland Rice Cultivar Coefficient Specific Parameters for DSSAT (Version 4.7)-CERES-Rice Crop Simulation Model and Evaluation of the Crop Model under Different Temperature Treatments conditions
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作者 Shams Shaila Islam Ahmed Khairul Hasan 《American Journal of Plant Sciences》 2021年第5期782-795,共14页
To develop basis for strategic or arranged decision making towards crop yield improvement in Thailand, a new method in which crop models could be used is essential. Therefore, the objective of this study was to measur... To develop basis for strategic or arranged decision making towards crop yield improvement in Thailand, a new method in which crop models could be used is essential. Therefore, the objective of this study was to measure cultivar specific parameters by using DSSAT (v4.7) Cropping Simulation Model (CSM) with five upland rice genotypes namely Dawk Pa-yawm, Mai Tahk, Bow Leb Nahng, Dawk Kha 50 and Dawk Kahm. Experiment was laid out in a Completely Randomized Design (CRD) with split plot design. Results showed that five upland rice genotypes had significantly affected each other by different temperature treatments (28°C, 30°C, 32°C) with grain yield, tops weight, harvest index, flowering, and maturity date. At the same time, all the phenological traits had highly significant variation with the genotypes. The cultivar specific parameters obtained by using a temperature tolerant cultivar (Basmati 385) with five upland genotypes involved in the DSSAT4.7-CSM. Model evaluation results indicated that utilizing the estimated cultivar coefficient parameters, model simulated well with varying temperature treatments as indicated by the agreement index (d-statistic) closer to unity. Hence, it was estimated that model calibration and evaluation was realistic in the limits of test cropping seasons and that CSM fitted with cultivar specific parameters can be used in simulation studies for investigation, farm managing or decision making. This electronic document is a “live” template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document. 展开更多
关键词 DSSAT-CERES-Rice crop Simulation Model Temperature PHENOLOGY Upland Rice Genotypic Cultivar coefficient
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Seasonal variation of evapotranspiration,Priestley-Taylor coefficient and crop coefficient in diverse landscapes
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作者 Hantian Wu Weiwei Zhu Bo Huang 《Geography and Sustainability》 2021年第3期224-233,共10页
Priestley-Taylor equation(PT)and the Penman-Monteith equation(PM)are commonly used methods for regional evapotranspiration monitoring,using the PT coefficient(α_(a))and PM crop/vegetation coefficient(K_(c)).This pape... Priestley-Taylor equation(PT)and the Penman-Monteith equation(PM)are commonly used methods for regional evapotranspiration monitoring,using the PT coefficient(α_(a))and PM crop/vegetation coefficient(K_(c)).This paper investigates the seasonal changes inα_(a)and K_(c)at five sites in Australia and China,to understand the relation-ship between environmental conditions and evapotranspiration when applying different evaporation estimation methods.The research shows that higher actual evapotranspiration does not lead to higherα_(a)and K_(c)values.α_(a)and K_(c)perform similarly in cropland and forest environments in both China and Australia.Bothα_(a)and K_(c)continuously increase to a peak during the growing season and then decrease to their lowest values during the winter season.Considering K_(c)’s similar performance toα_(a)and its greater data processing requirements,K_(c)has few advantages for estimating regional evapotranspiration.Applying the Priestley-Taylor equation with a regional𝛼indicator will enhance the accuracy and reduce the workload when estimating regional evapotranspiration for similar landcover types based on remote sensing. 展开更多
关键词 crop coefficient Evapotranspiration riestley-Taylor coefficient easonal variation Landscapes
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Evaluation of Actual Evapotranspiration and Crop Coefficient in Carrot by Remote Sensing Methodology Using Drainage and River Water to Overcome Reduced Water Availability
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作者 Ali H. Hommadi Nadhir Al-Ansari +2 位作者 Hatem H. Hussien Rafat N. Abd Algan Ghaith M. Ali Majed 《Engineering(科研)》 CAS 2023年第5期352-366,共15页
Searching for alternative methods for traditional irrigation is World trend at days due to a reduction in water and increased of drought due to climate changes therefore farmers need use modern methods of scheduling w... Searching for alternative methods for traditional irrigation is World trend at days due to a reduction in water and increased of drought due to climate changes therefore farmers need use modern methods of scheduling water and minimizing water losses while also increasing yield. To meet the future increasing demands water and food there is a need to utilize alternative methods to reduce evaporation, transpiration and deep percolation of water. Any countries use recycled water (drain and sewage) and desalination water from the sea or drains to irrigate crops plus computing actual crop evapotranspiration (ET<sub>c</sub>) so as to calculate the amount of water to apply to a crop. The paper aims to assess the actual evaporation and evaporation coefficient of carrots, by planting carrots in a field and the crop was exposed to several sources of water (DW and RW) and comparing ET<sub>c</sub>, K<sub>c</sub> and production among plots of three sites (A, B and C). The study used two types of irrigation water (drain water (DW) and river water (RW)). The results were to monthly rate and accumulated actual evapotranspiration to C (irrigation by RW only) more than A (67% RW and 33% DW) and B (17% RW and 83% DW) via 7% and 58%, respectively. The yield to C more than A and B by 17% and 75%, respectively. In conclusion the use of DW can cause a reduction in crop consumptive of carrot crops also causes a reduction in yield, crop length, root length, root size, canopy of crop, number of leaves and biomass of the plant therefore, the drainage water needs to treated before irrigating crops And making use of it to irrigate the fields and fill the shortfall in the amount of water from the river. The drain water helped on filling the water shortage due to climate changes and giving production of carrot crop but less than river water. 展开更多
关键词 CARROT Reference Evapotranspiration Actual Evapotranspiration (ETa) Marginal Water crop coefficient Landsat Satellite
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南方丘陵区油茶蒸散量SIMdualKc模型估算
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作者 马彬 曹桓荣 +3 位作者 夏雄 熊娅 杨小霈 吴友杰 《节水灌溉》 北大核心 2024年第6期69-76,共8页
为探究SIMdualKc模型在南方丘陵区油茶林地的适用性,利用2 a油茶的野外实测生长季数据,率定和验证了双作物系数SIMdualKc模型在南方丘陵区油茶林地的各参数。率定后作物系数K_(cbini)=0.9,Kcbmid=0.92,K_(cbend)=0.77,土壤含水率验证结... 为探究SIMdualKc模型在南方丘陵区油茶林地的适用性,利用2 a油茶的野外实测生长季数据,率定和验证了双作物系数SIMdualKc模型在南方丘陵区油茶林地的各参数。率定后作物系数K_(cbini)=0.9,Kcbmid=0.92,K_(cbend)=0.77,土壤含水率验证结果R^(2)为0.918~0.979,MAE为0.019~0.021,RMSE为0.021~0.026,EF为0.876~0.957。通过叶面积指数数据输入方式的模拟效果比较,得出日变化叶面积指数模拟效果稍好,确定了Logistic生长函数计算得到叶面积指数的可靠性与适用性,并校准了油茶在水分胁迫条件下土壤含水率的模拟值。油茶夏梢期末以及秋梢期容易产生水分胁迫影响,2021年水分胁迫系数K的范围为[0.478,1],2022年为[0.182,1]。将水量平衡法计算得到的蒸散量作为实测值与模拟值进行比较,两者具有良好的一致性,R^(2)为0.52~0.61。研究结果可为南方丘陵地区油茶林地针对夏秋季节易发生高温干旱的自然灾害制定高效节水的灌溉制度提供理论依据。 展开更多
关键词 油茶 SIMdualkc模型 作物系数 水分胁迫 蒸散量
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基于SIMDualKc模型估算非充分灌水条件下温室番茄蒸发蒸腾量 被引量:15
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作者 石小虎 蔡焕杰 +2 位作者 赵丽丽 杨佩 王子申 《农业工程学报》 EI CAS CSCD 北大核心 2015年第22期131-138,共8页
为了探讨SIMDual Kc模型在西北地区温室环境不同水分处理的适用性,以番茄为材料,于2013-2015年在陕西省杨凌区温室内进行亏水处理试验,设置全生育期充分灌水处理、仅发育期亏水50%处理、发育期中期连续亏水50%和全部亏水50%共4种水分处... 为了探讨SIMDual Kc模型在西北地区温室环境不同水分处理的适用性,以番茄为材料,于2013-2015年在陕西省杨凌区温室内进行亏水处理试验,设置全生育期充分灌水处理、仅发育期亏水50%处理、发育期中期连续亏水50%和全部亏水50%共4种水分处理,通过2013-2014年试验数据对SIMDual Kc模型进行率定,采用2014-2015年试验数据对模型进行验证,并通过模型将土壤蒸发量和番茄蒸腾量分开,利用模拟结果分析不同水分处理对土壤蒸发量和番茄蒸腾量的影响。结果表明:模型模拟不同水分处理蒸发蒸腾量与实测值有较好的一致性,其绝对误差为0.22~0.33 mm/d,均方根误差为0.26~0.48 mm/d、决定系数为0.51~0.81。该模型可以准确的将不同水分处理土壤蒸发量和作物蒸腾量分开,且土壤蒸发量模拟值与实测值有较好的一致性,其绝对误差为0.016~0.024 mm/d,均方根误差为0.013~0.034 mm/d和决定系数为0.63~0.84;通过模拟得到的番茄蒸腾量计算不同水分处理的水分亏缺系数,研究表明水分亏缺系数随亏水时间的增加而降低,复水后水分亏缺系数有不同程度的增加,且发育期、中期和后期连续亏水50%时,后期时水分亏缺系数降到最低,为0.63。因此该模型在西北地区温室环境下非充分灌溉条件下有一定的适用性。除此之外,研究通过模拟结果分析非充分灌水下番茄的响应及复水后的补偿机制,为非充分灌水条件下番茄栽培提供理论依据。 展开更多
关键词 温室 灌溉 模型 番茄 亏水处理 作物系数 水分亏缺系数
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双作物系数模型SIMDual_Kc的验证及应用 被引量:13
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作者 赵娜娜 刘钰 +1 位作者 蔡甲冰 L.S.Pereira 《农业工程学报》 EI CAS CSCD 北大核心 2011年第2期89-95,共7页
为了将棵间蒸发与叶面蒸腾有效地分开,该文利用3 a冬小麦的田间实测数据(土壤含水率和实际腾发量),率定和验证双作物系数模型SIMDual_Kc在华北地区的适用性,并计算各生育阶段以及整个生育期冬小麦棵间蒸发量占作物腾发量比例。结果表明... 为了将棵间蒸发与叶面蒸腾有效地分开,该文利用3 a冬小麦的田间实测数据(土壤含水率和实际腾发量),率定和验证双作物系数模型SIMDual_Kc在华北地区的适用性,并计算各生育阶段以及整个生育期冬小麦棵间蒸发量占作物腾发量比例。结果表明,模型模拟土壤含水率及实际腾发量的效果均比较好,拟合度较高。模型所模拟的棵间蒸发变化过程趋势明显,与作物生长阶段密切相关,整个生育期棵间蒸发量占作物腾发量比例在17%~22%左右变化,此模型在华北地区具有一定的适用性。 展开更多
关键词 模型 蒸发 蒸腾 作物腾发量 作物系数
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Assessing Crop Water Demand and Deficit for the Growth of Spring Highland Barley in Tibet, China 被引量:25
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作者 LIU Zhao-fei YAO Zhi-jun +1 位作者 YU Cheng-qun ZHONG Zhi-ming 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第3期541-551,共11页
The aim of this study was to assess the crop water demand and deficit of spring highland barley and discuss suitable irrigation systems for different regions in Tibet, China. Long-term trends in reference crop evapotr... The aim of this study was to assess the crop water demand and deficit of spring highland barley and discuss suitable irrigation systems for different regions in Tibet, China. Long-term trends in reference crop evapotranspiration and crop water demand were analyzed in different regions, together with crop water demand and deficit of spring highland barley under different precipitation frequencies. Results showed that precipitation trends during growth stages did not benefit the growth of spring highland barley. The crop coefficient of spring highland barley in Tibet was 0.87 and crop water demand was 389.0 ram. In general, a water deficit was found in Tibet, because precipitation was lower than water consumption of spring highland barley. The most severe water deficit were in the jointing to heading stage and the heading to wax ripeness stage, which are the most important growth stages for spring highland barley; water deficit in these two stages would be harmful to the yield. Water deficit showed different characteristics in different regions. In conclusion, irrigation systems may be more successful if based on an analysis of water deficit within different growth stages and in different regions. 展开更多
关键词 TIBET highland barley PENMAN-MONTEITH reference crop evapotranspiration crop water requirement crop coefficient crop water deficit
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基于SIMDual_Kc模型估算非充分灌水条件下冬小麦蒸散量 被引量:7
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作者 郑珍 王子凯 蔡焕杰 《排灌机械工程学报》 EI CSCD 北大核心 2020年第2期212-216,共5页
为研究关中冬小麦植株蒸腾和土壤蒸发规律,利用2 a冬小麦小区控水试验实测数据,率定和验证了双作物系数SIMDual_Kc模型在关中地区的适用性.用大型称重式蒸渗仪的实测蒸散量值(或水量平衡法计算值)与模型模拟值进行对比.结果表明:SIMDual... 为研究关中冬小麦植株蒸腾和土壤蒸发规律,利用2 a冬小麦小区控水试验实测数据,率定和验证了双作物系数SIMDual_Kc模型在关中地区的适用性.用大型称重式蒸渗仪的实测蒸散量值(或水量平衡法计算值)与模型模拟值进行对比.结果表明:SIMDual_Kc模型可较准确地模拟关中不同水分条件下冬小麦蒸散量,且模拟精度较高.模型估算的平均绝对误差为0.6433 mm/d.模型估算的冬小麦初期、中期和后期的基础作物系数分别为0.35,1.30,0.20.另外,模型还可以较准确地估算不同水分供应条件下的土壤水分胁迫系数、土壤蒸发量和植株蒸散量.冬小麦整个生育期,土壤蒸发主要发生在作物生育前期,中期较低,后期略微增大;植株蒸腾主要发生在作物快速生长期和生长中期,整个生育期中呈先增大后减小的趋势. 展开更多
关键词 冬小麦 蒸散量 SIMDual_kc模型 作物系数 灌溉
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Sensitivity of Penman-Monteith Reference Crop Evapotranspiration in Tao'er River Basin of Northeastern China 被引量:16
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作者 LIANG Liqiao LI Lijuan +2 位作者 ZHANG Li LI Jiuyi LI Bin 《Chinese Geographical Science》 SCIE CSCD 2008年第4期340-347,共8页
A non-dimensional relative sensitivity coefficient was employed to predict the responses of reference crop evapotranspiration (ET0) to perturbation of four climate variables in Tao'er River Basin of the northeaste... A non-dimensional relative sensitivity coefficient was employed to predict the responses of reference crop evapotranspiration (ET0) to perturbation of four climate variables in Tao'er River Basin of the northeastern China. Mean monthly ET0 and yearly ET0 from 1961 to 2005 were estimated with the FAO-56 Penman-Monteith Equation. A 45-year historical dataset of average monthly maximum/minimum air temperature, mean air temperature, wind speed, sunshine hours and relative humidity from 15 meteorological stations was used in the analysis. Results show that: 1) Sensitivity coefficients of wind speed, air temperature and sunshine hours were positive except for those of air tem- perature of Arxan Meteorological Station, while those of relative humidity were all negative. Relative humidity was the most sensitive variable in general for the Tao'er River Basin, followed by sunshine hours, wind speed and air tem- perature. 2) Similar to climate variable, monthly sensitivity coefficients exhibit large annual fluctuations. 3) Sensitivity coefficients for four climate variables all showed significant trends in seasonal/yearly series. Also, sensitivity coefficients of air temperature, sunshine hours and wind speed all showed significant trends in spring. 4) Among all sensitiv- ity coefficients, the average yearly sensitivity coefficient of relative humidity was highest throughout the basin and showed largest spatial variability. Longitudinal distribution of sensitivity coefficients for air temperature, relative hu- midity and sunshine hours was also found, which was similar to the distribution of the three climate variables. 展开更多
关键词 reference crop evapotranspiration Penman-Monteith Equation sensitivity coefficient Tao'er River Basin
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Crop Water Requirements in Egypt Using Remote Sensing Techniques
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作者 Mohammed A. El-Shirbeny Abd-Elraouf M. Ali Nasser H. Saleh 《Journal of Agricultural Chemistry and Environment》 2014年第2期57-65,共9页
The common Soil in Egypt is clay soil so common irrigation system is tradition surface irrigation with 60% irrigation efficiency. Agricultural sector consumes more than 80% of water resources under surface irrigation ... The common Soil in Egypt is clay soil so common irrigation system is tradition surface irrigation with 60% irrigation efficiency. Agricultural sector consumes more than 80% of water resources under surface irrigation (tradition methods). In arid and semi-arid regions consumptive use is the best index for irrigation requirements. A large part of the irrigation water applied to farm land is consumed by Evapotranspiration (ET). Irrigation water consumption under each of the physical and climatic conditions for large scale will be easier with remote sensing techniques. In Egypt, Agricultural cycle is often tow agricultural seasons yearly;summer and winter. Common summer crops are Maize, Rice and Cotton while common winter crops are Clover and Wheat. Landsat8 bands 4 and 5 provide Red (R) and Near Infra-Red (NIR) measurements and it used to calculate Normalized Deference Vegetation Index (NDVI) and monitoring cultivated areas. The cultivated land area was 3,277,311 ha in August 2013. In this paper Kc = 2 * NDVI ? 0.2 represents the relation between crop coefficient (Kc) and NDVI. Kc and Reference evapotranspiration (ETo) used to estimate ETc in Egypt. The main objective of this paper is studying the potential crop Evapotranspiration in Egypt using remote sensing techniques. 展开更多
关键词 Normalized DEFERENCE Vegetation Index (NDVI) Reference EVAPOTRANSPIRATION (ETo) Landsat8 crop coefficient (kc) crop EVAPOTRANSPIRATION (ETc) and ARID Region
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Crop Evapotranspiration Estimation through the,Use of Satellite Images
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作者 Enrique Palacios-Velez Hector Flores-Magdaleno 《Journal of Earth Science and Engineering》 2013年第10期663-671,共9页
An efficient water use requires accurate estimations of crop ET (evapotranspiration). However, an accurate ET estimation is really difficult to achieve when big regions such as irrigation districts or complete water... An efficient water use requires accurate estimations of crop ET (evapotranspiration). However, an accurate ET estimation is really difficult to achieve when big regions such as irrigation districts or complete watersheds are involved. Satellite images are an alternative that can be used to estimate accurate crop ET for big regions. In the present study, two known methods were used to estimate crop ET, the METRIC model which was developed by the University of Idaho and a Kc-NDVI relationship. In the METRIC model, ET is estimated as a residual of the energy balance equation. The second method uses reference ET, and estimates a crop coefficient (K,.) as a linear function of the NDVI vegetation index. ET was estimated in a section of the Rio Mayo Irrigation District located in Sonora, Mexico using Landsat 7 satellite images. Crop ET of the main crops was estimated. Results show some differences between both methods. An average ET depth of 460 mm for the wheat average growing season was found when using METRIC, while an average ET depth of 421 mm was found when using the Kc-NDVI relationship. A water use total efficiency of 62% and 63% was found for METRIC and the Kc-NDVI relationship, respectively. 展开更多
关键词 crop evapotranspiration crop coefficient METRIC NDVI.
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Evaluating agricultural water-use efficiency based on water footprint of crop values: a case study in Xinjiang of China
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作者 HAI Yang LONG Aihua +3 位作者 ZHANG Pei DENG Xiaoya LI Junfeng DENG Mingjiang 《Journal of Arid Land》 SCIE CSCD 2020年第4期580-593,共14页
Efficient agricultural water use is crucial for food safety and water conservation on a global scale. To quantitatively investigate the agricultural water-use efficiency in regions exhibiting the complex agricultural ... Efficient agricultural water use is crucial for food safety and water conservation on a global scale. To quantitatively investigate the agricultural water-use efficiency in regions exhibiting the complex agricultural structure, this study developed an indicator named water footprint of crop values(WFV) that is based on the water footprint of crop production. Defined as the water volume used to produce a unit price of crop(m^3/CNY), the new indicator makes it feasible to directly compare the water footprint of different crops from an economic perspective, so as to comprehensively evaluate the water-use efficiency under the complex planting structure. On the basis of WFV, the study further proposed an indicator of structural water-use coefficient(SWUC), which is represented by the ratio of water-use efficiency for a given planting structure to the water efficiency for a reference crop and can quantitatively describe the impact of planting structure on agricultural water efficiency. Then, a case study was implemented in Xinjiang Uygur Autonomous Region of China. The temporal and spatial variations of WFV were assessed for the planting industries in 14 prefectures and cities of Xinjiang between 1991 and 2015. In addition, contribution rate analysis of WFV for different prefectures and cities was conducted to evaluate the variations of WFV caused by different influencing factors: agricultural input, climatic factors, and planting structure. Results from these analyses indicated first that the average WFV of planting industries in Xinjiang significantly decreased from 0.293 m^3/CNY in 1991 to 0.153 m^3/CNY in 2015, corresponding to an average annual change rate of –3.532%. WFV in 13 prefectures and cities(with the exception of Karamay) has declined significantly during the period of 1991–2015, indicating that agricultural water-use efficient has effectively improved. Second, the average SWUC in Xinjiang decreased from 1.17 to 1.08 m^3/CNY in the 1990 s, and then declined to 1.00 m^3/CNY in 2011–2015. The value of SWUC was highly consistent with the relative value of WFV in most prefectures and cities, showing that planting structure is one of the primary factors affecting regional agricultural water-use efficiency. Third, the contribution rate of WFV variations from human factors including agricultural input and planting structure was much more significant than that from climatic factors. However, the distribution of agricultural input and the adjustment of planting structure significantly differed among prefectures and cities, suggesting regional imbalances of agricultural development. This study indicated the feasibility and effectiveness of controlling agricultural water use through increasing technical input and rational selection of crops in the face of impending climate change. Specifically, we concluded that, the rational application of chemical fertilizers, the development of the fruit industry, and the strict restriction of the cotton industry should be implemented to improve the agricultural water-use efficiency in Xinjiang. 展开更多
关键词 agricultural input climatic factors contribution rate planting structure structural water-use coefficient water footprint of crop values
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Research in Agrometeorolgy on Fodder Crops in Central India—An Overview
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作者 Suchit K. Rai Probir K. Ghosh +1 位作者 Sunil Kumar Jitendra B. Singh 《Atmospheric and Climate Sciences》 2014年第1期78-91,共14页
Livestock rearing is one of the major occupations in India and is making significant contribution to the country GDP. The regional and seasonal variations in the teperature and rainfall distribution have been the majo... Livestock rearing is one of the major occupations in India and is making significant contribution to the country GDP. The regional and seasonal variations in the teperature and rainfall distribution have been the major factors influencing the economy of a region. It is a matter of serious concern that out of 11 districts of central India, 9 districts are showing increasing trend in maximum temperature with a rate of 0.01°C to 0.15°C/year. A significant long-term decreasing trend (Slope = -4.26) was found in annual rainfall series at Jhansi. At Jhansi, moderate to severe drought occurs once in five years. But in the last decade, 7 years experienced moderate to disastrous drought in Jhansi region, wherein rainfall deficiency ranged between 40% and 60% from normal value. Of special mention was the year, 2006, which experienced a worst drought ever recorded for this region. Studies related to crop simulation model was carried out for fodder sorghum and its application for agronomic management and assessing the impact of climate change. Crop modeling studies on forage sorghum (C4) and cowpea (C3) showed increased dry matter biomass by 3% in sorghum but more prominent in cowpea by 46% under elevated CO2 from 330 ppm to 770 ppm. The interaction study of enhanced CO2 and temperature showed prominent negative impact on yields of both the crops. Evapotranspiration and crop coefficient (Kc) of several fodder crops i.e. berseem, lucerne, oat, sorghum, teosinte, maize + cowpea, guinea + berseem were worked out. In berseem, the highest Kc (1.81) was found during 2nd cutting followed by 3rd and 4th cuts. Estimates on irrigation scheduling for the guinea grass + berseem showed that the cropping system requires 7 irrigations at an interval ranging from 13 to 30 days to fulfill the 567.6 mm of water per season as net irrigation under mar soil (black) type whose actual water holding capacity (AWHC) is 175 mm. Similarly, if the cropping system is grown under kabar (AHWC = 140 mm) soil, then it requires nine irrigation with a total water requirement of 591.5 mm at an interval ranging from 10 to 24 days. For integrated pest management (IPM) scheme of lucerne, degree day based model was developed to monitor the lucerne weevil population in central region. 展开更多
关键词 Temperature Rainfall Trend DROUGHT crop Simulation MODEL CLIMATE Change Validation Calibiration Sensitivity Analysis CLIMATE Risk Management EVAPOTRANSPIRATION crop coefficient DEGREE-DAY MODEL and Growth Models
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