The Effct Of Wartermelon Continuous Cropping Obstacle On Different Fertilizer Under Different Preceding Crop

Watermelon needs six years to rotation before to plant again because of continuouscropping obstacles. But with the structural adjustment of rural land the crop rotation isdifficult to implement. The continuous cropping area of watermelon increases year by yearand that has seriously affected the yield and quality of watermelon. Therefore, the researchabout the environmental conditions of continuous cropping soil and the growth and quality ofwatermelon under fertilizing and rotation of crops is important to solve the problem of thewatermelon continuous cropping obstacle.This test used cabbage and garlic as the preceding crops and discussed the effect of thechemical fertilizer and three organic fertilizers and their combined application on the plantgrowth and watermelon quality in continuous cropping soil environment. The results showedas follows:1. The effect on soil nutrient content: Compared with chemical fertilizer, organic andorganic-inorganic fertilizer could increased the levels of soil available N, P, K and soil organiccarbon effectively. Seaweed organic fertilizer treatment with cabbage as the preceding crophad the highest content of soil available N, P and K while the double potassium bio-organicfertilizer treatment with garlic as the preceding crop had the highest soil available nitrogencontent. And the later treatment had the highest soil organic content. Under the same fertilizerprocessing, available nitrogen, available potassium and organic matter content of the soil withcabbage as the preceding crop were higher than the garlic treatment which had higher rapidavailable phosphorus.2. The effect on soil microflora: With the extension of watermelon growth period, the soilfungi quantity of cow dung treatment increased at first and decreased later while the soil fungiquantity of other treatment showed a trend of decrease. The number of soil bacteria all thetreatments reduced after an increase trend. The soil actinomyces quantity of the treatmentwith cabbage as the preceding crop decreased first and reduced again before an increase whilethe tendency of the garlic treatment was to rise first and then decline. It showed that thepreceding crop was in favor of the increase of the soil actinomyces quantity.With the same preceding crop, organic fertilizer and organic-inorganic fertilizer couldeffectively reduce the content of soil fungi and increase the number of soil bacteria and actinomycetes compared with chemical fertilizer. The effect of the organic fertilizer alone wasbetter than the mixture of organic and chemical fertilizer.In the organic fertilizer the double potassium biological organic fertilizer had the bestsoil microflora and the treatment with cow dung had the highest content of soil fungi. In thesame period with the same fertilizer processing, the number of soil fungi of garlic treatmentwas lower significantly than cabbage treatment and it promoted the proliferation of soilbacteria and actinomycetes in the later growth stage of watermelon.3. The effect on soil enzyme activity: With the extension of watermelon growth period, soilinvertase and urease activity of all the treatments with various fertilizer conduct had the trendto rise first and then decline while the soil catalase activity reduced fist and the increased. Theproteinase activity of treatment with cabbage as preceding crop increased and then decline.The proteinase activity of garlic treatments had the trend to rise first and increase again beforea decline. It showed that the garlic treatment was favor of the improvement of proteinaseactivity.With the same preceding crop, the organic fertilizer and organic-chemical fertilizer couldimprove the soil enzyme activity in later growth stage of watermelon while in the early stagethe organic-chemical fertilizer was better than organic fertilizer alone. The soil protease andcatalase activity of the combination of cow dung and chemical fertilizer was the highest aswell as the soil urease activity of seaweed organic fertilizer. Potassium and double biologicalorganic fertilizer had the highest soil invertase activity in harvest. In the same period with thesame fertilizer processing, the garlic treatments promoted the soil urease and proteinaseactivity of organic fertilizer and compound fertilizer in the late growth stage of watermelonand cabbage increased treatment improved the soil invertase activity in the same stage.4. Effect on plant vegetative growth of watermelon: The watermelon stem diameter、plantheight of organic fertilizer and chemical fertilizer mixed treatment are better than that oforganic fertilizer alone; In contrast, organic fertilizer can promoted the growth of watermelonleaves. At the same time, under the same fertilizer treatment, garlic increase the watermelonplant vegetative growth is better than Chinese cabbage, the treatment of garlic rotation withcow dung can promoted the watermelon plant vegetative growth best.5. Effect on quality of watermelon: organic fertilizer and organic-inorganic compoundfertilizer could reduce the thick of fruit peel, and increase the weight of single fruit, solublesolids and soluble protein content in the centre of watermelon, which is best by using thedouble K bio-organic fertilizer and chemical fertilizer, yet the sugar content and solubleprotein content is very low when using seaweed fertilizer. The yields of watermelon inrotation of garlic with watermelon was significantly higher than rotation of cabbage with watermelon, but no obvious difference was found in the thick of fruit peel, indexes of fruitshape, soluble solids and soluble protein content among the two crop rotation system.Synthesizing all kinds of target about soil index, plant growing status and fruit quality inwatermelon continuous cropping ground, the results showed that the soil environment ofgarlic and watermelon rotation system receiving organic-inorganic compound fertilizer wereimproved effectively, and the suitable cultivated measure can not only keep high quality, butalso increase the yields. Finally, that was one of the effective methods for relieving thecontinuous cropping obstacles in watermelon.