Effects Of Tobacco-coix Rotation On Yield And Quality Of Coix

In order to explore the changes in soil nutrients,enzyme activities and microbial quantity in coix fields under tobacco-coix rotation and coix continuous cropping,the influence of tobacco rotation on the growth,development,yield and quality of coix plants was elucidated,and certain theoretical basis and practical guidance were provided for the continuous high-yield and high-quality production path of coix.From2020 to 2021,the experiment was conducted at four sites in Xiashan Town and Tunjiao Town,Xingren City,Qianxiang Subdistrict of Anlong County,and Longchang Town of Zhenfeng County,Qianxinan Prefecture,Guizhou Province,to study the changes in soil nutrients,enzyme activities and microbial quantity of Coix under coix rotation and coix continuous cropping,and to compare the differences in root growth,photosynthetic characteristics,dry matter and nutrient accumulation,yield and quality of Coix coix,and to clarify the regulatory effects of coix rotation on coix production,quality,growth and development and soil.The main findings are as follows:1.Tobacco coix rotation increases soil total phosphorus,available phosphorus and available potassium content,while increasing soil enzyme activity and microbial number.Coix rotation and coix cropping had little effect on soil p H in coix fields.Compared with coix continuous cropping,the total phosphorus,available phosphorus and available potassium contents of the nicotta coix rotation were increased by 5.43%,27.74% and 66.43%,respectively,of which the soil available potassium content difference reached a significant level,while the soil total nitrogen content decreased by an average of 3.36% during the growth period of coix.At the same time,the rotation of tobacco coix increased the activity of related enzymes affecting soil fertility,so that the activities of soil catalase,sucrase,urease and acid phosphatase were higher than those of coix coix,which was beneficial to soil carbon and nitrogen conversion.Moreover,compared with coix continuous cropping,the number of bacteria and actinomycetes in the soil of coix rotation increased by 84.26% and18.61%,respectively,and the number of fungi decreased by 28.06%,thereby significantly increasing the total amount of soil microorganisms and B/F value.This shows that the rotation of tobacco coix improves the soil environment of microbial survival,promotes the growth and reproduction of microorganisms,increases the number,and is beneficial to soil nutrient cycling.2.Tobacco coix rotation significantly promotes coix root growth.Compared with coix continuous cropping,the total root length,root surface area,root volume,root diameter,root tip number and root branch number of coix continuous cropping were significantly higher than those of coix coix during the growth period of coix coix continuous cropping,which were 43.67%,48.06%,38.27%,31.26%,respectively.52.97% and 54.24% showed that flue-cured tobacco could improve the spatial distribution of coix roots in the soil after crop rotation,promote root growth,affect the growth and development of plants in the aboveground parts,make the plant height higher,the stem thicker and larger,and then affect the photosynthetic characteristics of the plant canopy.3.Tobacco coix rotation increases the fluorescence parameters of coix,which in turn significantly improves the photosynthesis of coix.Compared with coix continuous cropping,the chlorophyll fluorescence indexes of coix Fv/Fm,ΦPSII,NPQ and q P were higher than those of continuous cropping,which were 1.85%,5.20%,4.43% and 21.72% higher than those of continuous cropping,respectively,so that the leaves of coix plants used more light energy for photosynthesis,and by adjusting the balance of non-photochemical quenching and photochemical quenching by themselves,they achieved the purpose of protecting themselves and promoting plant photosynthesis,thereby improving the net photosynthetic rate and stomatal conductivity of a single plant.The intercellular CO2 concentration and transpiration rate increased by 34.80%,47.76%,36.24% and 28.20%,respectively,which reached significant levels.4.Tobacco coix rotation significantly increased the dry matter accumulation and nutrient accumulation of coix,thereby improving the nutrient absorption and utilization efficiency of plants.Compared with coix continuous cropping,the dry matter accumulation and nitrogen,phosphorus and potassium nutrient accumulation of coix plants were significantly increased after flue-cured tobacco rotation,which made the contribution rate of plant dry matter and nitrogen,phosphorus and potassium nutrient transport greater,promoted the transfer of plant dry matter and nutrients to the grain,and provided a guarantee for the high yield of grain under the rotation of tobacco coix.At the same time,the nutrient uptake efficiency of nitrogen,phosphorus and potassium in the soil of the plants was improved by 0.21kg/kg,0.10kg/kg and 0.65kg/kg,and the utilization efficiency was increased by 3.37kg/kg,1.38kg/kg and 4.45kg/kg,respectively,and the harvest index was 4.51% higher.2.69% and 33.33%,indicating that after flue-cured tobacco rotation,the absorption of soil nutrients by coix was improved,the ineffective accumulation of plant accumulated nutrients in vegetative organs was reduced,and the accumulated nutrients were distributed more to the grains.5.Tobacco coix rotation significantly increased coix production.Compared with coix continuous cropping,the grain yield of coix was increased by an average of1415.70 kg/hm2 after flue-cured tobacco rotation,an increase of 34.80%.Among the yield traits,roasted coix rotation significantly increased the number of tillers(3.6)and grains per hole(458.3 grains),and increased the weight of 1,000 grains(10.47 g)and reduced the number of grains(41.4 grains).It is shown that roasted coix increased yield by increasing the number of grains per hole and the weight of 1,000 grains,and reducing the number of grains.And the correlation analysis showed that the root morphology of Coix was significantly or very significantly positively correlated with yield.6.Tobacco coix rotation improves coix grain quality.The soluble sugar content,starch content and lysine content of coix seeds increased significantly after the rotation of tobacco coix,and also increased the crude fat content but the difference was not significant,the content increased by 6.14%,34.34%,9.77% and 17.57%respectively,but the crude protein content of the grain was reduced by 1.50%compared with the continuous cropping of coix.In summary,flue-cured tobacco has improved soil quality after crop rotation,so that the soil total phosphorus,available phosphorus and available potassium content increased,soil enzyme activity increased,the number of microorganisms increased,providing a suitable environment for the distribution of plant roots in the soil,promoting the growth of plant roots and the development of aboveground parts,and the dry matter accumulation and nitrogen,phosphorus and potassium nutrient accumulation of coix were significantly increased,so that the yield of coix was improved and the quality was improved.