Effects Of Different Amount Of Wheat Straw On Vegetable Growth And Soil Properties In Protected Paddy Field

The problem of continuous cropping obstacle in greenhouse is becoming more and more serious.Many studies have shown that the continuous cropping obstacle can be effectively alleviated by water and drought rotation,and straw mulching is conducive to soil fertility.The experiment was carried out by the combination of water and drought rotation and straw mulching for continuous field return,submergence cultivation of water spinach in summer and autumn,and dry cultivation of cabbage in winter and spring.During the period of water cultivation,the experiment was carried out with the high-volume mulching of 2500 kg/mu and 1500 kg/mu,covering the wheat straw with a length of 10 cm.At the same time,the field experiment was further expanded,and the wheat straw was mechanically crushed to cover and return to the field,and the Hubei green stem taro was cultivated wet,to explore the improvement effect on the yield and quality of vegetables and soil properties,as well as the comprehensive effect of straw decomposition.The main results are as follows:1.During the period of submergence cultivation of water spinach,a high volume of 2500 kg/mu and 1500 kg/mu was used to cover 10 cm of short specification wheat straw and wet cultivation of water spinach.The results showed that the average decomposition rates of 2500 kg/mu and 1500 kg/mu were 62.28%and 84.15%respectively after 195 d decomposition.The yield of 1500 kg/mu treatment was increased by 22.73%compared with that of the control,and the application of chemical fertilizer was reduced by 34.30%,achieving the effect of reducing the application of chemical fertilizer and increasing the yield.After planting water spinach,the nitrate nitrogen of the treated soil decreased significantly,which alleviated the problem of soil salinization.The content of available P and K in the soil of 2500 kg/mu straw mulching treatment was significantly higher than that of the control,and the two treatments could supplement P and K elements in different degrees.In the second year,the content of soil organic carbon in the two treatments was significantly increased.In the third year,after adjusting the proportion of base fertilizer and covering the mechanical cutting section of wheat straw,the results showed that after 139 d decomposition in summer and autumn,the decomposition rate of 1500 kg/mu was as high as 90.41%,and that of 2500 kg/mu was 81.40%,which was significantly higher than that of 10cm in length in the previous two years.By applying more nitrogen fertilizer to adjust the ratio of carbon and nitrogen,the total yield of 1500 kg/mu treatment increased by 17.73%,and that of 2500 kg/mu treatment increased by 16.59%,from a small reduction in yield in the previous two years to a large increase in yield.2.During the dry cultivation of pakchoi,they were kept in the original cultivation box without changing soil.The results showed that in the second year,the yield of 2500 kg/mu and 1500 kg/mu increased 47.72%and 20.86%respectively compared with the control.The content of total potassium in pakchoi treatment plants was higher than that in the control.After planting pakchoi,the content of soil organic carbon and nitrate nitrogen were significantly increased,and the content of soil organic carbon in 2500 kg/mu grass mulching treatment was significantly higher than that in the control.For two consecutive years,the combination of water and drought rotation and straw mulching has greatly improved the yield of vegetables and soil nutrients.It can be seen that straw returning is a long-term accumulation process.At the same time,wheat straw returning can consider reducing the application of potassium fertilizer.3.During the field experiment cultivation of Hubei green stem taro,and the wheat straw was evenly covered in the taro ditch by mechanical crushing of 750 kg/mu and 1250 kg/mu to explore the decomposition effect of straw.The results showed that the decomposition of wheat straw was complete and did not affect the next stubble ploughing.The yield of the two treatments increased significantly.The yield of 1250 kg/mu and 750 kg/mu treatments increased by 96.63%and 83.67%,respectively.The content of organic carbon in the soil increased in 0-20 cm soil layer,mainly in the 0-10 cm soil layer.It can be seen that the smashed wheat straw soil was covered and returned to the field,and the Hubei green stem taro was fully wet cultivated,which had better effects on the increase of taro yield and the improvement of soil properties.Therefore,under the condition of high temperature and humidity in the facility in summer and autumn,continuous wheat straw returning to the field combined with water and drought rotation can not only improve the yield of the current crop and the next crop of vegetables,but also alleviate the soil salinization and improve the soil fertility.