Impact of Irrigational Recovery Water on Soil and Measures for Melioration in Ningxia

Ma Yunrui Miao Jiwen Zhang Yimin Wang Jie (Soil and Fertilizer Institute of Ningxia Academy of Agriculture and Forestry Sciences,Yinchuan 750002)

Irrigational recovery water;Soil salinization;Melioration measures.

It was found that under the condition of relatively poor drainage if it was irrigated with light salt water with a mineralizatiom degree of 1.3～1.6g/L the saline concentration,SAR,SDR,SSP,KMg of the soil increased with the lengthening of years of irrigation. It indicates that the salinization of the soil was aggravating resulting in decline of yield of dryland crops.So it is not feasible to irrigate soil of middle and light salinization with pure recovery water.It would not produce harm to soil and crops if mixed irrigation and totation irrigation of salt water and fresh water were adopted.If the soil was mulched for the whole growth period of wheat salinization would be controlled but the yield of wheat would decline.Covering the soil with straw would reduce land temperature on early spring and delay emergence of seedlings and had no effect on control of salinization.Applicatiion of organic manure and furfural residue had fairly good effect on melioration of soil and was benificial to exploitation of recovery water.