Study On Mulching Technology Of Toona Sinensis

Toona sinensis is an important economic tree species of Toona(End1.)Roem,Meliaceae in China.It has many uses such as material value,edible value and medicinal value.In this paper,the 5-year-old dwarf Toona sinensis was used as the research object,and three kinds of mulching treatments,including chaff mulching,wood chip mulching and straw mulching,were adopted in this paper.No mulching was treated as control group.By observing the budding and growth condition,bud nutrient composition,leaf photosynthesis parameters and soil physical and chemical properties of the forest were determined,the differences of various indicators were systematically analyzed,and the characteristics of different coverage measures were comprehensively evaluated,which laid a theoretical foundation for the ecological management technology of Toona sinensis in the central of Hunan province.The main findings are as follows:(1)Among the mulching treatments,the initial budding period of straw mulching was the earliest,and the number of buds and yield per plant increased the most,with the increase of 27.07%and 54.48%.The increase of plant ground diameter and plant height and the vesicle weight and the number of leaflet was the largest.The leaflet area of the wood chip mulching was the largest.In conclusion,chaff mulching and straw mulching were superior to the wood chip mulching and the control group.(2)The mulching treatment improves the nutritional ingredient and the mineral content in the Toona sinensis bud.The content of soluble protein,vitamin C9 calcium,iron and zinc in the buds of Toona sinensis was the highest in chaff mulching,which are 5.03mg/g,1.143mg/g,909.75mg/kg,386.13 mg/kg and 83.50mg/kg,and they were 87.69%,41.07%,56.20%,68.19%,101.20%higher than the control.The content of soluble protein was the highest in the buds of Toona sinensis in wood chip mulching,which was 0.576%,0.064%higher than the control.The magnesium in the buds of Toona sinensis in straw mulching was the highest,which was 254.50 mg/kg,14.84mg/kg higher than the control.(3)The mulching treatment improved the photosynthetic capacity of the leaves,and the net photosynthetic rate of straw mulching treatment was the highest,which was 8.82umol·m-2·s-1,41.12%higher than the control.The difference was significant.The effect of chaff mulching on the SPAD value of leaves was significant.The correlation analysis showed that the net photosynthetic rate was positively correlated with ground diameter increment,plant height increment,the vesicle weight,the leaflet area,and leaf water content,and significantly negatively correlated with specific leaf weight.(4)Mulching treatment has a certain effectt on the soil temperature and humidity of the Toona sinensis forest.In the budding stage,the mulching treatment made the soil temperature change slowly in a day.In the high temperature period,the soil temperature was lowered and the soil moisture content was increased,and the cooling effect was weakened with the deepening of the soil layer.Comprehensive analysis showed that straw mulching was the best way to reduce temperature and conserve moisture.(5)Mulching can improve soil structure,reduce soil bulk density,and increase soil total porosity.In 0-20cm soil layer,the bulk density of the treated soil was reduced by 0.03g/cm3-0.1 8g/cm3 compared with the control,and the total soil porosity was increased by 1.86%?10.57%compared with the control.In the 20-40cm soil layer,the bulk density of the treated soil decreased by 0.04g/cm3-0.16g/cm3 compared with the control,and the total soil porosity was 1.39%-7.03%higher than the control.According to the comprehensive analysis of the mulching treatment on the soil physical properties,wood chip mulching was the best(6)Mulching can improve the soil fertility of forest land,and the effect of 0-20cm soil layer was biggest than 20-40cm soil layer.The pH value of chaff mulching increased the most compared with the control.The contents of soil organic matter,nitrate nitrogen,ammonium nitrogen,total nitrogen and available potassium in straw mulching increased by 43.27%,108.14%,86.18%,98.68%and 39.43%,respectively.The available phosphorus content of the chaff mulching increased by 48.22%compared with the control.Correlation analysis showed that there was a positive correlation between soil nutrient elements,and there was a significant positive correlation between nitrate and ammonium nitrogen,total nitrogen and available potassium,and there was an extremely significant positive correlation between total nitrogen and ammonium nitrogen.According to the comprehensive analysis to the effect of mulching treatment on soil chemical properties,the straw mulching was the best.(7)According to the calculation of blur membership function method,the average value of the membership function of chaff mulching treatment was the largest,indicating that the chaff mulching treatment has the highest comprehensive evaluation.