Effect Of Soil Melioration And Yield Increase With Different Agronomic Measures In Salinization Blocked Farmland In The North China Plain

The North China Plain is the most important grain production base where damage of soil salinization and secondary salinization are still existent after long-term large-scale management. This paper is based on salinization blocked farmland in the North China Plain. Eight treatments are set, including straw mulching, irrigation 120m3/666.7m2, irrigation 160m3/666.7m2, irrigation 180m3/666.7m2, nitrogen fertilization of 0kg/666.7m2, nitrogen fertilization of 10kg/666.7m2, nitrogen fertilization of 20kg/666.7m2 and local regular management(CK). The main goal was to study dynamic variation of soil salinity, p H, electronic conductivity, soil nutrient, soil enzyme activity with different agronomic measures; and research variation of yield and 1000-grain weight of wheat or corn and variation of economic benefit, then provide a reference for the optimizing agronomic measures in salinization blocked farmland of the North China Plain.The results were as follows:1. Improvement effect of soil salinity varies with different agronomic measures in salinization blocked farmland of the North China Plain. Soil salinity is greatly undulate with irrigation in surface soil layer, and the improvement effect of salinized soil with irrigation is irrigation 180m3/666.7m2>irrigation 160m3/666.7m2>irrigation 120m3/666.7m2. And the improvement effect of salinized soil under straw mulching is between irrigation and nitrogen management in 0 ~ 20 cm and 20 ~ 40 cm layer. The improvement effect is better under nitrogen management, with which soil salinity is stable. Soil salinity has a maximum value in June and a minimum value in September.2. Soil p H is reducing with time under different agronomic measures in 0~10cm and10~20cm. Soil p H is highest under different measures in 0~40cm layer. Soil p H raises first then goes down with the increase of soil depth under same measure, soil p H has a highest value in 10~20cm layer; Soil p H under other measures is lower than CK. Soil p H in June is higher than that in September under irrigation and nitrogen 0kg/666.7m2, which is the same as soil electronic conductivity.3. Soil nutrient is concentrated in 0~20cm layer. Variation of soil nutrient is not obvious, because surface of soil is disturbed strongly. Soil organic matter is increasing with growth of irrigation, and soil organic matter increases and then decreases with the increasing of nitrogen. Soil Soil organic matter with straw mulching is significantly higher than that with CK. Soil total nitrogen and available nitrogen have the same rule under different measures. Soil available phosphorus is behaved best with nitrogen 10kg/666.7m2, nitrogen 20kg/666.7m2 and irrigation 80 mm.4. Straw mulching, irrigation and nitrogen management can significantly enhance activities of soil urease and sucrase in 0~20cm layer. Compared with local average fertilization and irrigation, soil urease activity increased by 51.07%, 47.75% and 63.68%, respectively, under the conditions of straw mulching, irrigating 60 mm every time and nitrogen fertilization of 20kg/666.7m2. Also, soil invertase activity was enhanced by 95.24% and 81.04%, respectively, under straw mulching and nitrogen fertilization of 150kg/hm2. Straw mulching and moderate increasing nitrogen should be promoted in salinization blocked farmland of the North China Plain.5. The effect of wheat yield among three managements is nitrogen management> irrigation> straw mulching. Compared with CK, wheat yield with irrigation 160m3/666.7m2 has 10.52% rate of increase, and wheat yield under nitrogen 10kg/666.7m2, nitrogen 20kg/666.7m2 increase by 19.28%, 23.48% respectively, and wheat yield under straw mulching increases by 4.20%. Three measures raise the corn yield and straw mulching is the major factor. Economic benefit is great under nitrogen 20kg/666.7m2, irrigation 160m3/666.7m2 and straw mulching and respectively increases by 30.03%, 15.52% and 14.10%. Nitrogen 20kg/666.7m2 has the highest economic benefit. Considering all the factors, the order from high to low is nitrogen 10kg/666.7m2> irrigation 160m3/666.7m2>straw mulching>nitrogen 20kg/666.7m2>irrigation 120m3/666.7m2>CK>nitrogen 0kg/666.7m2> irrigation 180m3/666.7m2. Key words: Agronomic Measure; Salinization Blocked Farmland; Soil Melioration and Yield Increase;...