Study On The Movement And Distribution Of Anions In Greenhouse Soil Under Different Irrigations

The content of salt ions in soil increased when different kinds of fertilizer were put into soil for plant growth. Generally speaking, cations had less effect on salt concentration of soil solution, while the anions had more effect. The reason was that the soil colloid particles were being with negative charge and they could adsorb cations. Based on the productive practice of solar greenhouse in China, this subject studied the movement, distribution and movement theory of NO3-, SO42- and Cl- in greenhouse soil. This project laid foundation for scientific fertilization and provided theoretical basis for alleviating salt damage in soil. The main results were as follows:1. Under flooding and film irrigation, the content of NO3-, SO42- and Cl- decreased gradually because the cucumber adsorbed the nutrient and the water took some anions away.2. Under flooding fashion, the content of anions in soil decreased more than film irrigation. The content of NO3- and Cl- was about 50㎎/㎏ and the content of SO42- was about 120㎎/㎏ at the end of cucumber growth. The content of anions decreased more than the beginning. Under the film irrigation, The content of NO3- and Cl- was about 100㎎/㎏ and the content of SO42- was about 200㎎/㎏ at the end of cucumber growth.3. The movement of NO3-,SO42- and Cl- shaped a sphere or an ellipsoid with a point. The content of anions which were near the drip decreased while the farther increased under film irrigation. Under the effect of cucumber adsorbing and water flooding, the content of anions in soil decreased gradually which were 0-15㎝ far away from drip. The content of anions near the drip decreased more than the farther. The content of anions in 10-15㎝ horizontal direction soil decreased less. The content of anions in vertical direction soil 0-10㎝ were more than another two soil layers at the end of cucumber growth.4. SO42- was more adsorbed by soil colloid and it lost less with flooding water. NO3- and Cl- lost in soil with flooding water conveniently. They lost much to the depth of soil. In the end, the content of NO3- and Cl- in soil was little.5. The three kinds of anions increased the relative electrolytic leakage, content of Electronic Leakage, SOD, POD and CAT and decreased the roots activity. The intensity effect was Cl-> SO42-> NO3-. The three kinds of anions were accumulated in soil because of the continuous cropping cucumber. They made greater damage to cucumber than which were in flooding irrigation.