| Watermelon is one of the main horticultural crops planted in China.With the adjustment of the agricultural industry structure and the limitation of cultivated land area,continuous cropping is inevitable,so the problem of continuous cropping will follow.The watermelon wilt disease caused by continuous cropping can cause a large number of watermelons to reduce production,and even severe production,which seriously restricts the sustainable development of the watermelon industry.Studies have shown that the addition of crop straw can reduce the number of Fusarium oxysporum in the soil,but the current research on the effect of adding straw on the growth of continuous watermelon and soil nutrients is not much research.In this study,the effect of different added wheat straw on the growth index,physiological index and disease of Fusarium oxysporum was studied by using small watermelon variety Zajia 84-24 as a test material.The rhizosphere soil nutrients and soil of different sampling periods were also studied.Changes in enzyme activity;under laboratory conditions,the effects of wheat straw addition on soil respiration intensity and soil microbial biomass carbon and nitrogen were studied.The test is divided into two parts,one is the pot experiment and the other is the field test.The following conclusions are drawn from the above test:1.The effect of adding wheat straw under different soil conditions is different.2.Mature soil for five years of continuous cropping:(1)Adding wheat straw to the potted plant can increase the plant height,stem diameter and dry weight of the plant,and also have certain effects on the nutrient of the plant,and the best effect is to add 1% straw.(2)Adding wheat straw can significantly increase the chlorophyll content of potted watermelon leaves.(3)The addition of wheat straw can significantly reduce the incidence and disease index of potted watermelon wilt,and the best effect is to add 1%.(4)In the pot experiment of adding wheat sub-stalk twice,with the increase of colonization time,the contents of alkali nitrogen,available potassium,organic matter and total nitrogen in the soil increased significantly,the p H value decreased significantly,and the EC value increased significantly.(5)Adding wheat straw can increase the activity of urease,sucrase,phosphatase and catalase in potted watermelon.(6)Adding wheat straw can increase the intensity of soil respiration in the initial stage of pot experiment;the biomass nitrogen in potted watermelon soil is significantly increased by adding wheat straw.3.Continuous two-year-old oyster soil:(1)in the first year of adding wheat straw in the field,can increase plant height,stem diameter,inhibit fresh weight and dry weight,no significant effect on plant nitrogen,phosphorus and potassium content;In the second year after the addition of wheat straw,there was no significant effect on plant height stem diameter,but the addition of 1% straw treatment significantly increased dry weight and G value.(2)The addition of wheat straw had no significant effect on the chlorophyll content of Datian watermelon.(3)The addition of wheat straw in the field trial did not reduce the incidence and disease index of Fusarium wilt.(4)Adding wheat straw in the field can significantly increase the content of alkali nitrogen,available potassium and organic matter and have a certain sustained effect.(5)In the first year of adding wheat straw in the field,the activity of soil urease,sucrase,phosphatase and catalase can be increased to some extent;the second year after adding wheat straw in the field,urease The effects of sucrase and phosphatase activities were not significant,but significantly increased the activity of catalase.(6)In the second year of the field experiment,the soil respiration intensity was reduced at the beginning of the experiment;the addition of wheat straw increased the microbial biomass carbon content of the field test soil,and the addition of wheat straw in the field had a certain effect on the microbial biomass nitrogen content. |
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