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[Objective] This paper aims to provide theoretical and technical support for the efficient pesticide application of spring potato in high altitude areas of Guizhou. [Method] A field experiment was conducted on Weiyu 5, to explore the effects of different pesticide application dosage on disease index and biological effect of spring potato in Guizhou. [Result] After spraying the potato seedling rate were 89. 63% — 93. 37%, the disease index were 2.71% — 6. 17%. Compared with CK, the yield, number of single tuber and the yield of single plant increased by 1.55% —22.97%,2. 50% —30.00%,and 12.29% —42.68%,respectively. The best performance was obtained with 80% of the customary spraying dose. Pesticide spraying can significantly improve reducing sugar and starch content of potato, increase the reducing sugar content by 0. 01 —0. 14 percentage and starch content by 0.76 —7.43 percentage compared with CK. But the nitrogen, phosphorus, potassium and moisture content were not obviously affected. In terms of soil nutrient changes, the contents of soil organic matter, available potassium, available phosphorus, and alkalize nitrogen were increased by 6. 96% — 15. 47%, 1 . 75 — 36. 84%, 3. 57% —56. 09% and 10. 00% —14.99% respectively compared with CK. [Conclusion] In summary, 80% of customary spraying dose is recommended for high-yielding dryland spring potato cultivation in Guizhou. [ABSTRACT FROM AUTHOR]

The effects of potassium sulfate, potassium chloride and proper potassium deduction amount on potato growth, yield, economic benefit and potassium utilization rate were studied by the randomized block design to provide the theoretical basis for high-yield cultivation and efficient potassium utilization in potato production in single cropping region of Guizhou. Results: The potato yield is no significant difference between potassium sulfate and potassium chloride under the same potassium amount.The potassium fertilizer application amount in yellow soil with a high fertility can be decreased by 10 %.Potassium sulfate is suitably used as topdressing by stages but potassium chloride is suitably used as basal application and topdressing by stages.The input-output ratio of potato planted in yellow soil with a lower soil fertility reaches 3.79 under applying potassium chloride based on the application amount of the convention potassium( 150 K2 O kg/hm2). The agronomic efficiency, physiological efficiency and current utilization efficiency of potassium fertilizer in soils with lower and higher fertility is up to 25.98- 33.34, 46.80- 78.85 kg/kg and 41.74 %- 56.70 %, separately. [ABSTRACT FROM AUTHOR]

Effects of potassium fertilizing amount (0, 60, 120, 240, 360 k/hm2) on potato dry matter accumulation, potassium absorption and utilization efficiency were studied to provide a scientific reference for potassium management in high-yield cultivation of potato. Results: (i) The accumulation amount of dry matter and potassium increased with potato growing. The dynamic changes could be fitted with Logistic equation. (ii) Compared with the treatment without applying potassium fertilizer, optimum potassium fertilizer (120, 240, 360 kg/hm2) could significantly enhance the accumulation amounts of dry matter and potassium 60 days after seedling emergence, while decreased 70 days later, which was still higher than the treatment without applying potassium fertilizer. (iii) Applying potassium fertilizer delayed the occurrence time of maximum accumulation rates of dry matter and potassium. And the higher the later. (iv) When potassium fertilizing amount was 120 kg/hm2，the yield reached 35 269 kg/hm2，and the agronomic efficiency and utilization rate were significantly higher than high-potassium treatments (240, 360 kg/hm2). [ABSTRACT FROM AUTHOR]