疏勒河灌区新垦盐碱地洗盐定额试

根据疏勒河灌区新垦盐碱地土壤含盐量高，需采用水平明沟排水冲洗改良的实际，开展了不同冲洗定额的洗盐效果试验研究，提出了排盐地区系数经验公式与冲洗定额对数函数计算公式。根据表层土壤含盐量高的特点，提出了以0~30cm土层作为冲洗改良盐碱地脱盐控制层的准则，并制定了相应的洗盐定额。     

排盐补淡对滨海盐碱土壤盐分变化的影响

为明确增加地下水埋深及补淡淋洗对滨海盐碱土的脱盐效果,以期为滨海盐碱土壤改良及水资源合理利用提供科学依据。以浅井排盐和灌溉水、降雨淋洗作为排盐补淡措施,在距排盐井不同半径处对地下水位和1 m土层含盐量进行测定,研究其在排盐补淡过程中的变化情况。研究表明,利用4 m左右的简易浅井可有效增加地下水埋深,抽水区域地下水埋深围绕排盐井呈现"V"型变化;排盐对中度和重度盐碱土1 m土层含盐量的影响存在差异,中度盐碱土表现抑盐、重度盐碱土有脱盐效果,且都随着抽提半径的增大,抑盐脱盐效果减弱;灌溉或降雨对盐碱土壤有脱盐作用,抽水腾出土壤水库容会提高土壤脱盐率,比仅灌溉或降雨分别高34.22%和17.53%,接近水量的灌水处理比降雨效果明显。综上所述,增加地下水埋深、腾空土壤水库容可以有效抑制盐碱土壤返盐并提高灌溉水、降雨等淡水洗盐效率,加大土壤脱盐效果。     

微咸水入渗土壤水盐运移特征分析

提高水分的淋洗脱盐效率也是节水的一个重要途径。通过室内垂直入渗试验研究了淋洗水量、入渗水质和土壤初始含水量对土壤脱盐状况和水分洗盐效果的影响。结果表明,脱盐深度随入渗水量的增加呈幂函数增加,随入渗水矿化度和土壤初始含水量的增加而减小;脱盐区土壤平均含盐量随累积入渗量的增加而减少,随入渗水矿化度和土壤初始含水量的增加而增加。水分的脱盐效率随淋洗水量的增加呈幂函数减小,随入渗水矿化度的增加线性减少。土壤初始含水量对初期水分脱盐效率有影响,但对后期水分脱盐效率影响不大。对脱盐效率影响因素的分析可以为设计合理的淋洗水量提供参考。     

微成水入渗土壤水盐运移特征分析

提高水分的淋洗脱盐效率也是节水的一个重要途径。通过室内垂直入渗试验研究了淋洗水量、入渗水质和土壤初始含水量对土壤脱盐状况和水分洗盐效果的影响。结果表明，脱盐深度随入渗水量的增加呈幂函数增加。随入渗水矿化度和土壤初始含水量的增加而减小；脱盐区土壤平均含盐量随累积入渗量的增加而减少，随入渗水矿化度和土壤初始含水量的增加而增加。水分的脱盐效率随淋洗水量的增加呈幂函数减小，随入渗水矿化度的增加线性减少。土壤初始含水量对初期水分脱盐效率有影响，但对后期水分脱盐效率影响不大。对脱盐效率影响因素的分析可以为设计合理的淋洗水量提供参考。     

滨海盐碱地暗管工程设计参数研究

为了探索滨海滩涂盐碱地区暗管洗盐工程设计参数,运用溶质运移理论分析了脱盐标准与冲洗时间及冲洗定额之间的关系,研究了暗管工程设计参数（埋深、间距、管径）的影响因素及其理论模型,提出了牛顿迭代法计算方法。通过实例分析验证,得出暗管参数设计理论及方法是合理的,排水区的盐渍化土壤处于脱盐状态,满足作物生长发育的要求,为我国盐碱...     

不同水量淋洗方式下滨海盐渍土改良效果

选择对江苏沿海区域滨海盐渍土进行室内土柱模拟淋洗试验,采用3个不同梯度灌水量淋洗方式比较不同灌水量淋洗条件下、不同盐分梯度盐渍土的改良效果。结果表明,灌水淋洗能明显降低盐渍土含盐量,在充足水量情况下洗盐效果显著;不同层位间土壤脱盐效果呈现不同趋势:灌水淋洗过程中,上层土壤均有明显的脱盐效果,下层土壤在大水量淋洗情况下土壤整体脱盐效果明显,小水量淋洗情况下,效果不明显,且出现积盐现象;经不同梯度水量持续淋洗,对土壤脱盐率进行组间差异性t检验,不同梯度灌水量情况下土壤脱盐率呈极显著差异。     

不同灌溉方式下枣树根区土壤洗盐效果试验

在不同的灌溉方式及灌水量条件下,对红枣根区的洗盐效果开展了试验研究,研究结果表明,当灌水量分别为30 L和40 L时,滴灌和坑灌的洗盐效果最佳区城在1040 cm土层内,但同时增加了4060 cm红枣根系层土壤盐分的累积程度,会对红枣的生长发育产生不利.而注灌对红枣根系层4060 cm的洗盐优势较为明显,洗盐效果最佳的...     

不同矿化度对层状土入渗规律的影响研究

为研究不同矿化度水分对沙壤土中壤土夹层入渗规律的影响,设置4种矿化度处理,分别为0,1,3,5g/L,进行室内土柱垂直一维积水入渗试验。结果表明:壤土夹层对不同矿化度水分均有阻渗作用;各处理累积入渗量在湿润锋到达夹层界面前随时间呈非线性变化,通过夹层后随时间呈线性变化,各处理稳渗率大小关系为V(3g/L)>V(5g/L)>V(1g/L)+>V(0g/L);矿化度为0~3g/L时,累积入渗量、入渗后土壤含水率均随矿化度提高而增大;入渗结束后,各处理夹层界面上层土壤脱盐,夹层界面下层土壤积盐。     

盐碱地滴灌春小麦土壤水盐运动特点

通过测坑试验,测定水平和垂直方向距滴灌带不同位置土壤含水率和含盐量.结果表明,小麦滴灌条件下土壤水盐分布受滴灌影响深度主要在0～60 cm土层,0～20 cm土层水盐变化最剧烈.小麦主根系层土壤在垂直和水平方向一定范围内(垂直20 cm、水平25 cm)形成一个盐分淡化区,在0～100 cm土壤剖面内,土壤含水率随土层深度呈先升后降变化.土壤盐分在0～40 cm处于脱盐状态,60～100 cm积盐.上层土壤水盐受灌水和蒸发的影响随时间均升降交替变化,土壤盐分在非灌水期间呈表层和深层双聚、耕层脱盐特点.     

有垂向入渗时土壤的洗滤脱盐

垂向入渗条件下土壤的洗滤淡化脱盐问题,是水利土壤改良生产实践中经常碰到的问题。本文着重对渠道排水、垂向渗滤的土壤脱盐为典型,研究了浓度时、空分布的准确表达式,并以此求算洗滤地块中的盐分浓度的分布和变化,其结果对实际有一定参考价值。     

石羊河流域咸水灌溉对土壤物理性质的影响

为揭示咸水灌溉对土壤水力特性的影响机制,探求西北内陆干旱地区的合理灌溉模式,对石羊河流域中游地区开展制种玉米咸水灌溉田间试验,通过设置4种灌溉水矿化度水平(0.71,3.00,6.00,9.00 g/L),研究土壤盐分对土壤容重、孔隙度、质地和饱和导水率的影响.研究结果表明:对土壤进行咸水灌溉会引起土壤容重、孔隙度的改变,从而改变土壤饱和导水率.随着灌水次数的增多,各个处理土壤容重都越来越大,孔隙度越来越小,从而使得饱和导水率越来越小.此外咸水灌溉还会引起土壤质地的改变,特别是黏粒含量的增大,会使土壤饱和导水率减小.研究成果对咸水资源的高效利用及农业的可持续发展,具有重要的理论意义和实用价值.     

Influence of different water quantities and qualities on lemon trees and soil salt distribution at the Jordan Valley

The influences of water quantity and quality on young lemon trees (Eureka) were studied at the University of Jordan Research Station at the Jordan Valley for 5 years (1996–2000). Five water levels and three water qualities were imposed via trickle irrigation system on clay loam soil. The primary effect of excess salinity is that it renders less water available to plants although some is still present in the root zone. Lemon trees water requirements should be modified year by year since planting according to the percentage shaded area, and this will lead into substantial water saving. Both evaporation from class A pan and the percentage shaded area can be used to give a satisfactory estimate of the lemon trees water requirement at the different growth stages. The highest lemon fruit yield was at irrigation water depth equal to evaporation depth from class A pan when corrected for tree canopy percentage area. Increasing irrigation water salinity 3.7 times increased average crop root zone salinity by about 3.8–4.1 times.The high salt concentration at the soil surface is due to high evaporation rate from wetted areas and the nature of soil water distribution associated with drip irrigation system. Then, the salt concentration decreased until the second depth, thereafter, salt concentration followed the bulb shape of the wetted soil volume under trickle irrigation. Irrigation water salinity is very important factor that should be managed with limited (deficit) irrigation. But increasing amount of applied saline water could result in a negative effect on crop yield and environment such as increasing average crop root zone salinity, nutrient leaching, water logging, increasing the drainage water load of salinity which might pollute ground water and other water sources.     

内蒙古河套灌区耕地与荒地间水盐补排规律的研究

在野外实测资料的基础上,针对内蒙古河套灌区耕地与荒地间水盐补排关系与水盐运移规律,利用水盐平衡原理,对灌区内耕地间隙分布的荒地进行水分和盐分运移平衡研究。研究显示,耕地盐分部分向荒地迁移,荒地对灌区盐分分布具有调节作用。耕地每年平均有28.1%的灌溉水浸入荒地,荒地每年积盐268.5 g/m2,为灌溉水盐分的38.3%。研究为灌区水盐科学及区域水盐管理提供科学依据,对河套灌区可持续发展具有重要意义。     

The rehabilitation of an irrigation system along the Yellow River

The People's Victory Irrigation System which diverts water from the Yellow River of China covers a total irrigable area of 59 000 ha. The system encountered some serious problems in the first decade of its operation — salinity and waterlogging of irrigated land, siltation of irrigation and drainage channels, as well as a low efficiency of water use. This paper describes a series of structural and functional measures which have been adopted in the past 24 years for the rehabilitation of the system, including: improvement of the existing drainage system and construction of new drainage system on agricultural land, conjunctive use of surface and groundwater supplies, a comprehensive programme to reduce the levels of siltation as well as the implementation of improved water management practices. A model for the optimal operation of the system by using system analysis theory as an aid in reducing the operation and maintenance (O & M) costs has been developed in recent years. The results are that the soil salinity has been controlled and the agricultural production has increased whilst the efficiency of water use has improved and the siltation levels reduced. Experience gained on this system has been successfully used in developing and managing other irrigation projects along the lower reaches of the Yellow River. The proposed procedure of solving the said optimal model has also embodied some benefits from reducing O & M costs in operation.     

新疆盐渍化灌区水盐平衡现状及对

以新疆农七师127团灌区为研究对象，通过区域水盐监测、水盐平衡计算与分析，对现有水盐状况是否满足盐分控制要求作出评价，并提出对策措施。研究结果表明，现状的水盐平衡条件不能满足控制盐分要求，其中引进的盐分只有大约40%从平衡区内排出，有60%左右的盐分滞留在平衡区内，其结果势必加重区域内土壤盐渍化的程度。如果按现状灌排条件和灌溉用水水质状况预测，每年1.5m深土壤剖面的平均积盐量约为0.037%。 为保持研究区水盐的持续平衡状态，水量排引比需达到0.3左右。为此，在进一步加强明沟排水系统建设的同时，需增设田间暗管排水。     

Irrigation with saline water: benefits and environmental impact

The shortage of water resources of good quality is becoming an important issue in the arid and semi-arid zones. For this reason the availability of water resources of marginal quality such as drainage water, saline groundwater and treated wastewater has become an important consideration. Nevertheless, the use of these waters in irrigated lands requires the control of soil salinity by means of leaching and drainage of excess water and salt. However, the leaching of salts, soil microelements and agro-chemicals can lower the quality of the drainage water in the irrigation scheme. The irrigation return flows with water or poor quality are a source of pollution of the surface water bodies situated downstream of the drainage outlet. Deep percolation could also contaminate the groundwater. Therefore, irrigation with saline water requires a comprehensive analysis even beyond the area where water is applied. The problem should be treated beyond the scope of the irrigation scheme, taking into consideration the groundwater and downstream surface water resources of the river basin. Consequently, the sustainable use of saline water in irrigated agriculture requires the control of soil salinity at the field level, a decrease in the amount of drainage water, and the disposal of the irrigation return flows in such a way that minimizes the side effects on the quality of downstream water resources. This paper describes the guidelines for a preliminary evaluation of the suitability of water for irrigation and the key factors for salinity control in lands irrigated with saline water. Options to improve the quality of the drainage water, strategies for the reuse of this water and alternatives for disposal of the outflow are also analysed. The final goal is to obtain sustainable agriculture and maintain the quality of the water resources in the river basin.     

暗管排水条件下微咸水灌溉对土壤盐分动态及夏玉米生长的影响

进行暗管排水条件下微咸水灌溉田间试验,设置3种暗管埋深,分别为80 cm(D1)、120 cm(D2)以及无暗管排水(D0),3种微咸水浓度,其电导率分别为0.78 dS/m(S1),3.75 dS/m(S2)和6.25 dS/m(S3),共9个处理,每个处理3组重复.试验结果表明:暗管排水措施可以有效排除微咸水灌溉过程中土壤中累积的盐分;在玉米全生育期内,暗管埋深D1条件下,3种浓度微咸水S1,S2和S3灌溉时根系土壤电导率分别下降了39.00%,31.56%和29.43%,暗管埋深D2条件下,根系土壤电导率则分别下降了31.91%,18.08%和7.44%;夏玉米干物质累积量、穗棒累积量和穗棒质量分配率及最终产量均随着微咸水浓度的升高而降低;在相同微咸水浓度下,不同暗管埋设条件下的夏玉米最终产量从大到小依次为D1,D2,D0;3种暗管埋设条件下的作物需水量从大到小依次为D0,D2,D1的规律;暗管埋深80 cm的处理(D1)下夏玉米水分利用效率最高,而未埋设暗管的处理(D0)水分利用效率最低;当暗管埋设条件一定时,夏玉米水分利用效率随微咸水浓度的升高呈逐渐降低的趋势.     

Model Studies on Salt and Water Balances at Konanki Pilot Area, Andhra Pradesh, India

The salt and water balances at Konanki pilot area in Nagarjunasagar project right canal command in Andhra Pradesh State of India were analysed using SALTMOD. The model was calibrated by using two-year data collected in the pilot area. From the calibration, the leaching efficiencies of the root and transition zone were estimated as 65% and the out going natural sub-surface drainage was determined as 50 mm per year. The model predicts that the root zone soil water salinity will be reduced to 4, 3 and 2.5 dS/m (from an initial value of 11.5 dS/m) during the first, second and third seasons within six years after installation of the drainage system. Next, the situation prior to the installation of the drainage system was reconstructed using the model. Finally, sensitivity analyses were made to study the effects of varying drain depth, spacing and amount of irrigation water applied on root zone salinity and depth to water table. Here, the model predicted that closer than the present spacing or further deepening of the drains from the present depth of 1 m to 1.4 m will not have any better influence on the reduction of the root zone salinity than in the present situation. These simulations also suggested that by applying 80% of the present amount of irrigation water, the root zone salinity can be brought down to 5 and 4 dS/m by second and fourth years, respectively and this will in turn reduce the problem of water logging and salinity to some extent.     

内蒙古河套灌区咸水灌溉的环境效应分析

研究了咸水灌溉对土壤水盐动态、地下水位、地下水质、作物生长及产量的影响。灌溉水源为黄河水和高矿化度地下水混合。咸水灌溉期间,土壤盐分有所增加,通过控制咸水灌溉定额,以及进行合理的黄河水秋浇灌溉,可以达到年度内土壤盐分动态平衡。咸水灌溉条件下,作物长势及产量基本不受影响。适宜合理的咸水灌溉不会造成环境恶化,而且对缓解河套灌区水资源紧张的矛盾有着重要意义。