Plastic Sheet-mulching for Yield Improvement of Summer Sweet Potato,Longshu 24

By the randomized block design,effects of using plastic sheets for mulching on the yield and quality of the summer sweet potatoes,Longshu 24,were studied.The results showed that the plastic sheet-mulching increased the yield significantly.The average fresh tuber yield was 55.13t.hm-2 from the two years experiment.It was higher than that of CK by 22.9%.The average yield of the sweet potato dry matters,from the two years experiment,was 15.92t.hm-2.It was higher than that of CK by 20.0%.The differences were significant.The dry matter content of the sweet potatoes was lower than that of CK by 0.7%,and the starch content was lower by 0.61%.There was no significant difference on the overall root quality during the harvest period.The reasons that the plastic sheet-mulching could promoted the sweet potato yield were believed to include:(a)the weight pre plant of the tuberous roots was increased significantly;(b)the T/R radio during early and mid growing stages was reduced,while the root development during the peak stage was enhanced with the mulching;(c)the soil′s volume weigh was decreased,porosity dicreased,permeability improved,and water content remained relatively stable which rendered the soil conditions conducive to the plant′s development;(d)the plastic sheet-mulching improved the soil ecological environment that benefited the root growth and development;and(e)the mulching encouraged the root thickening resulting in improved the plant′s nutrient and water absorption.The increased efficiency by the application of plastic sheet-mulching was found to be most significant,that is,every hectare could increase a net income of 13000 yuan.