共查询到19条相似文献，搜索用时 375 毫秒
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非充分灌溉研究现状及存在问题 总被引：9，自引：1，他引：9
介绍了非充分灌溉研究的理论基础，阐述了非充分灌溉研究中的作物-水模型及其敏感指标、土壤水分不足条件下作物蒸发蒸腾量的计算方法和有限水量在作物生育期内的最优分配问题，最后提出了对非充分灌溉问题的几点看法。 相似文献
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玉米不同生育期水分胁迫指标 总被引：4，自引：0，他引：4
采用田间小区实验，通过对玉米不同生育期、不同土壤水分条件下叶水势、气孔导度、光合作用、植株蒸腾、生理生态状况及产量形成的观测试验，并在总结已有成果的基础上，分析研究了玉米不同生育阶段的水分胁迫指标阈值，提出了玉米不同生育阶段的水分胁迫指标，为节水灌溉与灌溉管理提供了科学、实用的依据。 相似文献
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河西绿洲灌区主要作物需水量及作物系数试验研究 总被引：2，自引：0，他引：2
利用Penman-Monteith公式计算了甘肃张掖绿洲主要作物各生育期参考作物蒸散量,利用农田水量平衡方程及土壤水分胁迫系数计算了作物实际蒸发蒸腾量,并计算比较了充分灌溉和非充分灌溉条件下不同生育期作物需水特征,确定了非充分灌溉条件下主要作物的作物系数。结果表明,非充分灌溉条件下,主要作物各生育期需水规律和充分灌溉具有一致变化趋势。非充分灌溉条件下,小麦、玉米、马铃薯全生育期作物系数平均值分别为0.81、0.7和0.73。在全生育期当中,随生育期的延续,主要作物叶面蒸腾比例逐渐增大,棵间蒸发逐渐减少。 相似文献
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彭世彰 《中国农村水利水电》1992,(11)
1982年以来,于麦仁店灌溉试验站进行了控制土壤含水量水稻灌溉技术及水稻需水量的试验研究,其成果表明,采用节水高产的控制灌溉技术后,水稻耗水量大幅度下降,生理生态需水规律发生显著变化。文章从稻田土壤水分等生态环境的改善,以及水稻自身生理调节机能和适应能力变化等方面,分析了水稻节水机理,并对彭曼法在节水灌溉水稻需水量计算中的应用进行了探讨,提出了应力系数K_s的计算公式。 相似文献
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非充分灌溉制度对Jensen模型的敏感性分析 总被引：3，自引：0，他引：3
分析了非充分灌溉中作物各生育阶段最优耗水量及产量对Jensen模型的敏感性。基于灌溉制度优化模型,构建了非充分灌溉制度对Jensen模型的敏感度计算公式,并以北京永乐店试验站1998～1999年度冬小麦的水分生产函数为例,进行了非充分灌溉制度对Jensen模型的敏感性分析。结果表明:1Jensen模型参数λi的波动对最优灌溉制度以及产量的计算结果影响较小;2与返青—拔节、灌浆—成熟阶段相比,拔节—孕穗、孕穗—灌浆阶段的最优耗水量计算结果受参数λi波动的影响比较小;3与返青—拔节、灌浆—成熟阶段相比,拔节—孕穗、孕穗—灌浆阶段的Jensen模型参数λi波动对各阶段最优耗水量及产量的计算结果影响较小。 相似文献
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地表蒸散的测定与分割方法研究进展 总被引：1，自引：0，他引：1
地表蒸散研究一直受到水文、气象、水利、生态、农学等相关学科的高度关注,其分割结果更是水文计算、灌溉管理、产量估测、土壤水分预报及工程设计的基础与依据。从地表蒸散总量及其分量的测定方法出发,对目前国内外关于地表蒸散及其分量的测定方法进行了全面地评述,在此基础上介绍了地表蒸散的分割方法及其最新研究进展,并提出了地表蒸散测定及其分割方法在研究中存在的问题和未来发展方向。 相似文献
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关于提高作物水分生产率与建立作物生态需水区划问题的探讨 总被引：1，自引：0，他引：1
作物光合作用对土壤水分有明显的阈值反应，通过土壤水分预报，控制土壤水分较长期处在略多于阈值的范围，有利于提高作物水分生产率，大定额的蓄水灌溉有利于创造下湿上干的土壤水分剖面，可减少土壤蒸发，提高水分有效利用。率根据作物需水与年内得到降雨补偿程度进行作物种值区划，称之为作物生态需水区划，根据这一区划进行作物布局，有利于灌溉节水。根据作物生态需水区划，华北地区可分为四个地带：①双季作物需水补偿带；②双 相似文献
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关于提高作物水分生产率与建立作物生态需水区划问题的探讨 总被引：1，自引：0，他引：1
作物光合作用对土壤水分有明显的阈值反应。通过土壤水分预报,控制土壤水分较长期处在略多于阈值的范围,有利于提高作物水分生产率。大定额的蓄水灌溉有利于创造下湿上干的土壤水分剖面,可减少土壤蒸发,提高水分有效利用率。 根据作物需水与年内得到降雨的补偿程度进行作物种值区划,称之为作物生态需水区划。根据这一区划进行作物布局,有利于灌溉节水。 根据作物生态需水区划,华北地区可分为四个地带:①双季作物需水补偿带;②双季作物需水基本补偿带;③一季作物需水补偿带;④一季作物需水基本补偿带。 相似文献
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Relationships between available soil water and indicators of plant water status of sweet sorghum to be applied in irrigation scheduling 总被引：3，自引：0，他引：3
Optimal crop production depends greatly on available soil water, and it is therefore important to know when and how much
to irrigate in order to attain agronomic potential. In this work, plant indicators are used to assess water stress. These
are compared with available soil water to find the critical point for irrigation scheduling of sweet sorghum. The experimental
trial was carried out in Bečej, in the Vojvodina region, on a sweet sorghum crop, grown in moderate climatic conditions on
a well-drained, deep chernozemolic meadow soil. Plant indicators tested were predawn and midday leaf water potential and crop
and air temperature difference. All the methods were sensitive to water deficit in plants, but not all can be used for irrigation
scheduling. The predawn leaf water potential was the most reliable parameter among those tested due to its relative independence
from weather conditions and a valid indicator of plant water status. This was not the case with canopy-air temperature difference.
The predawn leaf water potential corelation with available soil water indicates that the threshold value for irrigation scheduling
of sweet sorghum is when the former has decreased to –0.45 MPa. This corresponds to a soil water depletion to about 10% of
available water in the active root zone. The canopy-air temperature difference was sufficiently sensitive to indicate the
onset of mild plant water stress, although it showed a certain threshold value when water shortage appeared, which occurred
when the air and canopy temperature were the same.
Received: 9 April 1996 相似文献
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在河西走廊张掖市甘州区党寨镇田家闸灌溉试验站开展了马铃薯不同生育期调亏灌溉的试验研究。在保持其他生育期土壤水分为正常灌溉（土壤含水率65%～75%）的情况下,在马铃薯的幼苗期、块茎形成期、块茎膨大期和淀粉积累期分别进行轻度（土壤含水率55%～65%）的调亏处理,以全生育期的正常灌溉作为对照,进行马铃薯生长指标、产量和水分利用的测定。试验结果表明,不同生育期水分调亏均引起马铃薯株高、茎粗和单株总生物量降低,其中块茎膨大期水分亏缺降低程度最为显著。调亏处理中,苗期轻度水分调亏处理马铃薯产量33 027.22 kg/hm2,与对照无显著差异,水分利用效率和灌溉水利用效率最高,分别达到6.91和9.38 kg/m3,而且能够显著提升马铃薯综合品质。而块茎形成期马铃薯产量和水分利用效率最低,仅分别为24 047.32 kg/hm2和5.85 kg/m3,且造成马铃薯品质下降。膜下滴灌调亏可促进水分利用效率和灌溉水利用效率提高,且苗期轻度水分调亏对马铃薯稳定提质和改善当地水分利用现状有积极意义。 相似文献
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亏缺灌溉对成龄库尔勒香梨产量与根系生长的影响 总被引：4，自引：0，他引：4
研究了亏缺灌溉对成龄库尔勒香梨树营养生长、果实生长与吸收根系分布的影响。香梨的生育中期,设计了4种土壤水分亏缺(灌前土壤水势下限):轻度胁迫(-100 kPa)、中度胁迫(-200 kPa)、重度胁迫(-300 kPa)和对照(-50 kPa)。灌溉系统为地表滴灌。试验结果表明,亏缺灌溉显著地减少了夏季剪枝量,提高了果实产量。充分灌溉条件下,香梨树根长密度从树行由内向外呈递减趋势,滴灌促进了湿润体内的吸收根系的发育;距树行0.5 m,根长密度随着深度的增加而减少;距树行1 m至1.5 m,根长密度随着深度的增加而增加;距树行2 m的非灌溉区,根长密度在垂直方向上变化不显著。为适应滴灌湿润体内水分胁迫,香梨树在湿润体内及非灌溉区的吸收根系的分布均发生了显著的调整。适度水分胁迫下的根长密度增加对香梨产量有促进作用。 相似文献
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Evaluation of crop water stress index for LEPA irrigated corn 总被引：6，自引：0，他引：6
This study was designed to evaluate the crop water stress index (CWSI) for low-energy precision application (LEPA) irrigated
corn (Zea mays L.) grown on slowly-permeable Pullman clay loam soil (fine, mixed, Torrertic Paleustoll) during the 1992 growing season at
Bushland, Tex. The effects of six different irrigation levels (100%, 80%, 60%, 40%, 20%, and 0% replenishment of soil water
depleted from the 1.5-m soil profile depth) on corn yields and the resulting CWSI were investigated. Irrigations were applied
in 25 mm increments to maintain the soil water in the 100% treatment within 60–80% of the “plant extractable soil water” using
LEPA technology, which wets alternate furrows only. The 1992 growing season was slightly wetter than normal. Thus, irrigation
water use was less than normal, but the corn dry matter and grain yield were still significantly increased by irrigation.
The yield, water use, and water use efficiency of fully irrigated corn were 1.246 kg/m2, 786 mm, and 1.34 kg/m3, respectively. CWSI was calculated from measurements of infrared canopy temperatures, ambient air temperatures, and vapor
pressure deficit values for the six irrigation levels. A “non-water-stressed baseline” equation for corn was developed using
the diurnal infrared canopy temperature measurements as T
c–T
a = 1.06–2.56 VPD, where T
c was the canopy temperature (°C), Ta was the air temperature (°C) and VPD was the vapor pressure deficit (kPa). Trends in
CWSI values were consistent with the soil water contents induced by the deficit irrigations. Both the dry matter and grain
yields decreased with increased soil water deficit. Minimal yield reductions were observed at a threshold CWSI value of 0.33
or less for corn. The CWSI was useful for evaluating crop water stress in corn and should be a valuable tool to assist irrigation
decision making together with soil water measurements and/or evapotranspiration models.
Received: 19 May 1998 相似文献
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《Agricultural Water Management》2004,64(2):169-181
Irrigation is necessary in order to produce sugarcane in semiarid south Texas, but water supplies are becoming increasing limited. Drip and sprinkler irrigation systems offer more precise water control than conventional furrow irrigation, but are more expensive. This study was conducted to evaluate four different methods (pan evaporation (Epan), evapotranspiration (ET), auto-tensiometers, manual tensiometers) for determining the amount of irrigation water to apply, and three different frequencies of water application on sugarcane, in order to make the most efficient use of available water using subsurface drip irrigation. The study was conducted over three sugarcane seasons: the plant crop and two ratoon crops. The amount of water applied based on the different methods varied from year to year, with the ET method prescribing the most water in the first ratoon crop but the least amount in the second ratoon. This was probably caused mostly by differences in annual weather conditions. The more frequently water was applied, the larger amount any method tended to prescribe, since more frequent applications resulted in keeping the soil profile fuller, therefore providing less capacity to store rainfall when it occurred. Number of stress days as determined by calculating a stress coefficient based on ET and soil water balance indicated a large amount of stress in the first ratoon but almost none in the second ratoon crop. Direct soil water monitoring indicated much less stress than the calculated levels. Growth measurements and sugarcane yields showed that the highest water applications resulted in the best responses, regardless of the scheduling method used. All irrigation scheduling methods were effective, prescribing similar amounts of water for a given season. Direct measurement using tensiometers gives the most accurate assessment of field conditions, but is expensive and labor intensive. Automated tensiometers were not very reliable. Pan evaporation and ET are effective once they are properly calibrated by developing appropriate coefficients for a particular region. Pan evaporation has been used for a long time, but it is more difficult to obtain reliable data compared to ET data from automated weather stations. 相似文献
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《Agricultural Water Management》1998,36(3):233-246
ISAREG is a model for simulation and evaluation of irrigation scheduling. The model performs the soil water balance and evaluates impacts of water stress on yields for different crops. It is now being used to support a water saving irrigation scheduling program in a pilot area in the North China plain. This paper reports on the calibration and validation of the model using independent data sets relative to winter wheat and summer maize. Data are originated from the Wangdu experimental station and concern a set of drainage lysimeters where diverse irrigation treatments were applied representing different strategies of deficit irrigation. The calibration of the model was performed by deriving the crop coefficients adapted to the local climatic conditions, and considering the soil freezing during winter. The validation of the model was performed using different data sets. Results show that the relative errors to estimate the soil water content averaged 5.3% for summer maize and 7.3% for the winter wheat. These results support the use of the model in the practice. 相似文献
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分析了四川简阳地区砂岩和土壤中的水分运动特性和砂岩中储存的水分对土壤水分补给量的多少。对当地的砂岩和土壤进行了水分特征曲线的测定试验、入渗试验和蒸发试验,并采用研究中常用模型对试验结果进行了拟合,通过对拟合结果的分析,得出了当地土壤和砂岩的水分特性,总结出了该地区表面土层在缺水时水分很容易被下部砂岩层补给,砂岩中的水分是作物利用的重要水资源的结论。这对于充分利用当地水资源,合理确定类似地质条件地区灌溉定额,解决无灌溉条件丘陵区作物缺水问题,实现农业节水灌溉有一定的参考价值。 相似文献