Effects Of White Clover As Green Manure On Growth And Quality Of Brassica Chinensis And Lactuca Sativa

The organic food is developing quickly with the healthy consciousness of people. The fertilizer used in the plant production, especially in the vegetable production, is turned to the organic from the chemical. White clover (Trifolium repens) is a famous leguminous species used as forage and landscape. The content of crude protein in the white clover is very high, and the rotted stems and leaves can provide the nitrogen nutrition as green manure. The greenbelt area of the white clover is rapidly expanding with the city and highway construction. There are many clipping leaves and stems unused every year. If we use them as green manure in the production of organic vegetable, it will be greatly bringing economic benefits in vegetable production.In order to discuss the feasibility of white clover as green manure in the production of organic vegetable, the experiments were conducted to investigate the effects of white clover as green manure on growth and quality of Brassica chinensis and lettuce (Lactuca sativa).The results of experiment in B. chinensis indicated that within 2 weeks after transplanting the plant height, top fresh weight and root fresh weight in the treatment with white clover as green manure(treatment 1) were significantly lower than that in control with none fertilizer, but significantly increased after two weeks of transplanting. The growth of B. chinensis in the treatment with 50% white clover as green manure was significantly better than that in treatment 1 and control after top dressing. The content of nitrate in the leaves in treatment 1 and the treatment with 50% white clover plus little ammonium sulphate as base fertilizer were lower and the soluble sugar higher than that in other fertilizer treatments, which indicated that the B. chinensis quality in that both treatments were superior to pure chemical fertilizer treatments.The results of experiment in lettuce indicated that the growth in all treatments was significantly increased in contrast to control with none fertilizer. In the same application of nitrogen, the growth of lettuce in the treatment with white clover as green manure (treatment 1) was significantly better than that in control. The growth of lettuce in the treatment with 50% white clover (treatment 5) as green manure was significantly better than that control after top dressing, and the height, the leaf width and the top fresh weight were significantly higher than treatment 1. The growth of lettuce in the treatment with 200% white clover as green manure (treatment 6) was significantly better than that in treatment 1 and treatment 5, but significantly lower than in the treatments with compound chemical fertilizer. The content of nitrate in the leaves of lettuce in treatment 1, trearment 6 and the treatment with 50% white clover plus little compound chemical fertilizer as base fertilizer were lower, and soluble sugar were higher than that in other treatments, which indicated that the lettuce quality in that three treatments were superior to pure chemical compound fertilizer treatments.