土地盐碱化是世界性的一个重大问题。克拉玛依农业开发区是新疆引额济克工程的配套建设项目，是该工程沿线中最大的农业开发区。由于当地的气候特点、土壤及水文地质条件，土壤的次生盐渍化威胁严重。灌水洗盐和改良土壤是开发利用的关键。本文采用田间实验、室内模拟、大面积调查，对开发区不同改良措施、不同灌溉情况下克拉玛依新垦土地盐分的动态变化进行了研究。运用溶质的对流弥散方程计算出了不同作物、不同土壤质地下的洗盐定额。利用EM38大地电导仪测量了近三万亩已耕作土地的电导值，分析了开发后土壤盐分变化。通过研究，得到了以下结果：1．施有机肥、粉煤灰和掺沙对土壤盐分的运移影响都较大，其中粉煤灰处理脱盐效果最好、作物出苗率最高，有机肥处理下盐分变化平稳、作物生长最好，试验结果显示如将粉煤灰和有机肥同时施用，效果可能更理想。掺沙对脱盐有利，但在其处理下土壤盐分变化较剧烈，草炭与其它处理相比，效果最不明显。2．室内模拟及田间试验显示在新垦土地上灌溉定额达400／亩才对耕层土壤有脱盐作用，600方／亩的灌溉定饿额对耕层的脱盐效果较好，灌水定额达到60方／亩左右比较合适。随着土壤含盐量下降，土壤碱性增强。3．0.75米和1.5米的EC等值线图大致相似，开发区土壤的盐分含量西南方较高，东北方盐分含量变化较大，开发区西北部盐分含量较低并且变化平缓。0.75米内盐分含量的变化比1．5米内盐分含量变化略大。调查结果显示，耕作过的土地表层都不同程度的积盐，土壤的侧向排盐现象不明显。4．应用非饱和土壤溶质运移理论的对流扩散方程提出了计算土壤洗盐定额的方法。计算得不同作物的冲洗定额为小麦358方/亩，玉米478方／亩，棉花467方／亩，高粱251方／亩，油葵291方／亩苜蓿298方/亩，西瓜220／亩。5，开发区现存的主要灌溉方式还是大水漫灌，理论计算与历史经验都告诉我们在克拉玛依农业开发区进行农业开发存在着较大的次生盐渍化威胁。实际监测结果显示在地面灌溉下水分向下渗漏严重，如果按这样的灌溉方式继续下去，灌溉水下渗补给地下水从而造成地下水位上升导致开发区发生次生盐渍化这一灾难性的后果将不可避免。在经过一年的灌溉淋洗后，耕层土壤含盐量有所下降、水分条件极大改善的情况下，采用先进的灌水技术，根据不同作物的需水规律，制定科学的灌溉制度，保证满足作物需要又不致继续向下渗漏：建立合理的施肥制度、实施科学的耕作措施和利用方式，保证土壤肥力不断提高，巩固脱盐效果是保证开发区土地持续利用的前提。The salinization of soil is a cosmopolitan serious problem .The agriculture exploitation area of Kelamayi is the conveyance system of the project drawing water from river Eerqisihe to Kelamayi, and also is the biggest agriculture exploitation area along the line of the project. Due to the climate^ the soil and the hydrogeology, the threaten of secondary salinization is critical when exploitation in this area for agriculture is carried. Improving the soil fertility and ameliorating the soil structure is the key problem for utilization. Through field experiment indoor simulation and survey in large area, the salt dynamic diversification under different methods of amelioration and different quantity of irrigation was researched. A new method was put forward for determining the suitable irrigation quota. The value of the earth conductance of the exploitation has been surveyed and some analysis about the salt diversification has been done after the exploitation on the area. The main results were as follows: 1. The effect of applying flyash> organic fertilizer and sand to soil desalting is obvious, of which applying flyash is the best for soil desalting and rate of emergency.and the diversification of salt is smooth and the plant growing is the best under the treatment of organic fertilizer, the result of the experiment show if applying that two materials at one time, the effect will more remarkable. Applying sand has some effect on soil desalting but the salt diversification is acute. The effect was not very clear under the treatment of peat. 2. The indoor experiment of successive irrigation under no evaporation and the experiment in the field show that the salt declined in plough layer only when the irrigation norm reached to 400m3/mu · a. The desalting effect in plough layer will be good when irrigation norm reached to 600 m3/mu · a, and each irrigation quantity is 60 m3/mu will be better. The pH augments with the salt declines. 3. The EC contour map of 1.5 and 0.75 is similar, the salt is heaver in the southwest, and the diversification is acute in the northeast. The salt in the northwest is lower and the diversification is smooth. The diversification in 1.5m is larger than the diversification in 0.75m. The survey result shows that there have the salt assembling in the surface layer more or less, the phenomena of the desalting in side direction is not remarkable. 4. A new method determining the desalting irrigation norm with convection dispersion equation is put forward. Some simple calculations have done based on the parameter of the soil in the experiment field for different plants. The result is: wheat is 358 m3/mu, maize is 478 m3/mu, cotton is 467m3/mu, Chinese sorghum is 251m3/mu, oil sunflower is 291m /mu, lucerne is 298m /mu and watermelon is 220m /mu. 5. The main method of irrigation in the exploited area is surface flooding currently. The result of academic calculation and the historical experiences tell us that there have larger dangers of second salinization in the agriculture exploitation area of Kelamayi. The actual monitoring shows that the downward leakage is serious under surface flooding. The groundwater level will rise and the secondary salinization will cannot avoid if the method of current irrigation is not change. Advanced irrigation method will be adopted and scientific irrigation project will be made when the salt in plough layer declined and water condition improved after a year irrigation, and establishing proper fertilizer regime applying scientific tilth method and using manner ensuring the continuous improvement of soil fertility and solidifying the desalting effect are the premises of the sustainable utilization
