Seeking Local Adapted Cultivation Methods To Improve The Winter Potato Production In Wenshan, Yunnan, China

Growing potato has been the only choice of people in the impoverished mountainous area of Wenshan to generate income for family expenses.The winter potato produced in this area is mainly exported as vegetables to other parts of world. Comparing potatoes produced in other seasons, winter potato has a higher market price, therefore better economic returns of growers. Although potato is widely grown in this area, yield per unit of land is low, partially due to the lack of good varieties and poor agronomy. The objective of this study was to develop optimum potato production agronomy adapted to the local soil and climatic conditions of Wenshan. This will serve as a key element to improve potato production, therefore, to increase the income of farmers at this cold and impoverished mountainous area. My study covered four topics and each topic was carried out in a separate experiment on two potato varieties (H88 and Yunshu 503) as outlined here:(1) Density effect-Planting density can influence the yield of the winter potato. This experiment was carried out in 5 different densities, i.e. 2600 plants/667 m2,3400 plants/667 m2,4200 plants/667 m2,5000 plants/667 m2,5800 and plants/667 m2 using Randomized Complete Block design. My result indicated that the optimum density for the winter potato in Wenshan ranged from 4200-5000 plants/667 m2.(2) Tillage systems-Tillage had a major influence on the yield of winter potato. Five tillage systems including traditional farming, minimum tillage plus rice straw mulch, no-tillage plus rice straw mulch, no-tillage plus ordinary plastic film and rice straw mulch, and no-tillage plus black plastic film and rice straw mulch were evaluated. My result indicated that no-tillage plus black plastic film and rice straw mulch can improve the growth conditions of winter potato in late stage by increasing soil temperature, minimizing frost damage, reducing water evaporation, leading to better tuber quality and higher marketable yield. (3) Application of N,P,K fertilizers-N.P. K fertilizers had a major impact on the yield and quality of winter potato. Potassium deficiency is very common in Wenshan state. Application of potassium fertilizer can increase tuber yield and improve tuber quality. Attention should be paid to a balanced application of nitrogen, phosphorus, potassium fertilizers in winter potato production. The correct ratio of the three essential elements in the soil can harmonize aboveground and underground developments of potato. (4) Calcium nitrate-Calcium nitrate can affect on the yield and quality of winter potato.This experiment included three treatments, i.e.10kg/66 m2,15 kg/667 m2,and 20 kg/667 m2.The fertilizers were applied at planting time and the plots were arranged according to Randomized Complete Block design. My analysis indicated the application of 20 kg/667 m2 of calcium nitrate at plating time yielded best result by significantly reducing the occurrence of internal brown spot and increasing yield.