Effects Of Different Cultivation Methods On Agronomic Traits And Yield Of Shanlan Upland Rice

Shanlan rice,a kind of upland rice,which is mainly distributed in Hainan Province,has the incredibly important social,ecological and economic values.However,most varieties show high plant height,poor plant type and low yield."Slash-and-burn"traditional cultivation is the characteristic of Shanlan upland rice cultivation,which doesn't conform to the new form of modern environmental protection and improvement of living environment and ecological environment.One of the most important factors restricting shanlan upland rice yield is weeds.There are amounts of kinds of main weeds in dry paddy field,which are characterized by fast propagation,vigorous growth and strong nutrient absorption.If they are not promptly eliminated,they will compete with upland rice for sunlight,heat,water and fertilizers,resulting in poor growth of rice,the yield decreases,and even no harvest.With the rapid development of social economy,the structure of rural peasants has changed,and a large number of young laborers have been transferred.It is an inevitable trend that the cultivation of rice changes to mechanization and simplification.Therefore,we study the effect of different cultivation methods on the agronomic traits of Shanlan upland rice,leading it to turn from traditional mountainous upland cultivation to paddy field.To seek new ways to develop high quality and quantity of Shanlan upland rice in the new situation,we should not only ensure that cultivation of Shanlan upland rice can protect the ecological environment,but also make sure high yield and high-quality in paddy field.The results of the study are as follows:1.The growth duration of mulching cultivation for Shanlan upland rice are shortened by 5-7 days with the comparison of non-mulching pattern.The result of soil moisture content during the growth duration has been found as follow:straw mulching>non-woven fabric mulching>non-mulching.Weed control is as follow:non-woven fabric mulching>straw mulching>non-mulching.The data of overall weed control of the non-woven fabric mulching and straw mulching are 59.62%-94.75%and 35%?74.43%respectively.Comparing with the non-mulching treatment,the actual yield of non-woven fabrics mulching increased by 3.3%,and the theoretical yield of non-woven fabrics and straws mulching increased by 21.29%and 8.43%,which the non-woven fabric mulching increased significantly,but no significant difference among straw mulching,non-woven fabric mulching and non-mulching.Rice cultivated in aerobic soil with mulching can not only increase yields,but also play a role in environmental protection such as water retention and weed control.Non-woven fabric mulching pattern is the most prominent method of weed controlling,soil moisture conservation and yield increase.2.Transforming aerobic cultivation of Shanlan upland rice to traditional flooded cultivation,each growth period was advanced,all yield's components performed well,and yield increased by 26.2%.Compared with the aerobic cultivation,traditional flooded cultivation can increase the root's diameter of the middle column area of stele,and diameter of middle column/root cross section area,accelerating the longitudinal transport rate of water and nutrients in the root.It also can increase the stalk's epidermis and fundamental tissue magnitudes of cell,but reduce epidermis and fundamental tissue.As a result,cells of the stalk was closely arranged and the toughness was improved.3.The direct-seeding pattern has led to the advancement of each growth period.And the growth duration is 11d and 6d earlier than transplanting and seedling-throwing.Yields are as follows:direct-seeding>seedling-throwing>transplanting.The yield of direct seeding is the highest,because transplanting and seedling-throwing can save seedlings,and the reduced number of seedlings has a greater effect on yield than yield's components.The panicle weight of transplanting is significantly higher than transplanting and seedling-throwing,indicating that the yield of transplanting is more potential than direct-seeding and seedling-throwing.Also,the transplanting and seedling-throwing's root water and nutrient delivery are more timely than the direct-seeding.The transport rate of water and mineral elements in the column are as fallow:transplanting>direct-seeding>seedling-throwing.The water absorption rate of seedling-throwing in root is greater than that of the direct-seeding and transplanting,but there is no significant difference between the direct-seeding and transplanting.Transplanting can increase the number of vascular bundles,reduce the distance from adjacent vascular bundles.Transplanting's cortex and basic tissues are small,epidermis and fundamental tissue magnitudes of cell are numerous,and the cells of stalk are arranged closely.Therefore,the plant of transplanting has unhindered water and nutrient transfer,in which the nutrient supply is sufficient,and has good lodging resistant ability.4.The different plant densities have the most significant effects on the panicle weight,effective panicles and yield of Shanlan upland rice.The optimal plant density of Shanlan upland rice is 16.5cm×25cm.