Effects Of Returning Maize Straw To Field In Summer On Soil Physicochemical Properties And Growth And Development Of Cucumber

Cucumber（Cucumis sativus L.）is one of the most cultivated vegetable crops in China,and one of the main vegetable crops with the largest facility cultivation area and widest planting range in Jiangsu Province.With the extension of facility cultivation years,the physical and chemical properties of soil deteriorated,soil secondary salinization,fusarium wilt and other continuous cropping obstacles increasingly appeared.It is an important way to solve the soil continuous cropping obstacle by rational crop rotation and supplementing organic matter especially returning green straw to the field.In order to provide theoretical and technical support for the healthy and sustainable development of cucumber industry,this experiment studied the effects of returning corn and ryegrass straw to field and returning corn straw to field with organic fertilizer in summer on the physical and chemical properties of greenhouse soil and the growth and development of cucumber.The main results are as follows:1.Soil physical properties,such as soil bulk density and total porosity,could be improved by seeding corn and returning ryegrass straw to the field in different periods.The effect of ryegrass straw returning to field was lower than that of corn straw returning to field.Under high temperature in summer,maize grows fast and can quickly absorb soil surplus nutrients.Therefore,after returning to the field,maize can significantly increase soil nutrient elements.However,ryegrass straw had little effect on supplementing soil elements after returning to the field due to its small amount of growth.The effect of returning corn straw to the field was better than that of ryegrass,and the effect of early sowing was better.The treatments of ryegrass and corn straw returning to the field can reduce soil acidification.The growth potential of cucumber plants under maize straw returning was better than that under ryegrass returning.Returning maize and ryegrass straw to the field at different sowing dates had significant effects on the fruit quality of cucumber,and the contents of soluble protein,soluble sugar,vitamin C,phenolic acid and total flavonoids in cucumber fruit were significantly increased compared with the control.Cucumber yield was significantly affected by corn and ryegrass straw returning in different periods.Cucumber yield was significantly increased by 27.1%compared with blank treatment after cucumber harvest in the spring of the next year.2.Returning corn straw to the field with different sowing densities could significantly improve soil physical properties.The 20×20 cm and 20×30 cm densities significantly reduced soil bulk density at 0-20 cm surface layer and increased soil porosity.Under high temperature in summer,maize grows fast and can quickly absorb soil surplus nutrients.Therefore,after returning to the field,maize can significantly increase soil nutrient elements.With the decrease of planting density of maize,the nutrient supplement of soil nitrogen,phosphorus and potassium increased during cucumber planting.When the planting density of maize was 20×20 cm and 20×30 cm,the cucumber plant had better growth potential,plant height,leaf number and 10-15 node length were all higher than those of the control,but there was no significant difference in the node position of the first female flower and the node rate of female flower.Returning corn straw to field significantly promoted the maturity of cucumber fruit,and the contents of soluble protein,soluble sugar,vitamin C,phenolic acid and total flavonoids in cucumber fruit were significantly increased compared with the control.Cucumber fruit number,cucumber fruit weight and cucumber yield all increased with the decrease of corn planting density.Cucumber yield in autumn of that year and spring of the next year under the treatment of corn straw returning at planting density of 10×20 cm,20×20cm and 20×30 cm was significantly higher than that of the control.The yield of cucumber in autumn of that year and spring of the next year increased by 25.2%and 14.6%,respectively.3.Returning corn straw with different sowing densities and applying organic fertilizer could significantly improve soil physical properties,significantly reduce soil bulk density at 0-20 cm surface layer and increase soil porosity;Under the 20×20 cm planting density,the contents of nitrogen,phosphorus and potassium in the soil of different organic fertilizer treatments were higher than those of the control in different periods,but there were no significant differences in most of the nutrient indexes in the soil between 600 kg/666.7m2 and 800kg/666.7m2 organic fertilizer treatments.The average plant height,leaf number and 10-15 node length of cucumber were all higher than those of the control,but there was no significant difference in the node position of the first female flower and the node percentage of female flower.Straw returning combined with organic fertilizer of 600 kg/666.7m2 and 800kg/666.7m2 significantly promoted the maturity of cucumber fruit,and the contents of soluble protein,soluble sugar,vitamin C,phenolic acid and total flavonoids in cucumber fruit were significantly increased compared with the control.The effects of different organic fertilizer application levels on cucumber yield were significant,and corn straw returning+organic fertilizer treatment had the effect of increasing cucumber yield,and the yield of 600 kg/666.7m2 organic fertilizer treatment increased by 25.6%compared with the control.