Study On Forming Technology Of Rice Straw Seedling Substrate Board

Rice is currently the food crop with the largest planting area in my country,with both total output and unit yield occupying the leading position.About 40% of the rice planting area in my country is machine-transplanted,and the quality of rice seedlings directly affects the quality and even the yield of machine-transplanted rice.The traditional method of raising seedlings directly uses the cultivated soil of the farmland as the substrate for raising seedlings.The operation process of this method is labor-intensive,which is inconvenient for transportation and standardized operations.Moreover,borrowing soil for raising seedlings for many years will cause serious damage to the soil cultivation layer.Therefore,based on the two important rice production problems of machine transplanting rice seedling raising and straw resource utilization,this study takes the production of straw matrix board as the research goal,and carries out research from three aspects: straw ripening agent,straw pretreatment method and straw matrix board blocking,in order to explore the feasibility of straw matrix making straw matrix board and its application,and establish a new method of green and sustainable utilization of rice straw,It also provides an important basis for the construction of light and simplified machine transplanted rice seedling raising system.The main results are as follows:1.Adding different single ripening agents into straw,comparing the apparent color change,pH,electrical conductivity,E4 / E6,wood fiber degradation rate and various nutrient indexes,it was found that the straw with ripening agent B had a high degree of color deepening and reached dark brown on the 30 th day of ripening;The overall change trend of pH is first decreasing and then increasing,which is significantly different from the addition of other ripening agents;After 30 days of ripening,the conductivity met the normal requirements of plants,and E4 / E6 was significantly lower than other treatments.At the same time,the degradation rate of lignin,hemicellulose and cellulose of straw added with humic agent B was higher than that of other humic agents,reaching 36.31%,33.62% and41.31% respectively on the 30 th day,and had the most significant effect on the change of nutrient content.2.A large number of rice straw were composted with a single composting agent and pretreatment.Comparing the changes of apparent temperature,pH,electrical conductivity,E4 / E6 and various nutrient indexes,it was found that the temperature of straw without alkali pretreatment and adding composting agent B increased rapidly,and the cumulative days of high-temperature and efficient composting reached 9 days;PH increased and decreased significantly;After 36 days of ripening,the electrical conductivity meets the normal requirements of the plant,and the germination index is greater than 80%.The pile has no toxic effect on the seeds.At the same time,the addition of humic agent B without alkali pretreatment also had the most significant change in nutrient content.3.The straw without pre alkali treatment and added with ripening agent B is used as raw material,and the non-toxic biological starch is used as adhesive to press the straw matrix into a plate.Compared with the size of mechanical stress,it is found that the mechanical stress can not be dispersed with both hands when it is between 8-25 n,and can not be dispersed with one hand when it is greater than 25 N.Considering the advantages of convenient transportation and high cost performance,the formula with 75 g / plate of starch glue E as the substrate was selected,and the cost was 0.885 yuan / plate.4.By comparing the physical properties of straw substrate,nutrient soil substrate and paddy soil substrate,the growth characteristics of aboveground and underground seedlings and the physiological and biochemical properties of seedlings,it is found that straw substrate has the characteristics of light bulk density,large total pores,good ventilation,strong water holding capacity and high water absorption.The appearance and morphological characteristics of seedlings raised by straw substrate board are seedling height,stem diameter,developed root system,long root and so on.The root shoot ratio of seedlings raised on straw substrate was the largest among the three substrate seedlings,which was0.66.The strong seedling index of seedlings raised on nutrient soil substrate and paddy soil substrate increased significantly by 30.38% and 11.96%.At the same time,the contents of superoxide dismutase,peroxidase,catalase and soluble protein of seedlings raised on straw substrate were higher than those in nutrient soil substrate and paddy soil substrate,and the content of malondialdehyde was lower than that in nutrient soil substrate and paddy soil substrate.5.Based on the research of straw ripening agent,straw pretreatment method and straw matrix board blocking,the processing process of straw matrix board by soaking,ripening,dehydration and pressing is summarized.To sum up,rice straw can be used as the raw material of rice seedling substrate,and the rice seedling substrate plate made by soaking,ripening,dehydration and pressing can meet the requirements of seedling cultivation.The development of straw substrate board can provide new ideas for the resource utilization of straw and the construction of light and simplified machine transplanted rice seedling raising system.