Effects of different dosages of phosphate fertilizer on yield，economic benefits and quality of winter potato in Guangdong province

In order to determine the suitable application rate of phosphate fertilizer for winter potato in Guangdong province，four phosphate dosages were designed in the field experiment to probe into the effects of different dosages of phosphate fertilizer on the yield，economic benefits，quality and NPK accumulation amounts in potato tubers in Pinghai Town，Huidong County. Four phosphate dosages（treatments） were 0，45.0，90.0 and 135.0 kg/hm2，marked as P0，P1，P2，P3，respectively，with each treatment being replicated three times by using completely random block design. The related physiological indices were detected after maturing of potato tubers， the results showed that：（1） Both total tuber yield（ 57 576.0 kg/hm2） and marketable yield（ 55 848.7 kg/hm2） of P1 treatment were higher，being 16.2% and 16.6% higher than those of P0 treatment，and significantly higher than those of P3 by 8.9% and 8.5%，respectively；（ 2） Both total tuber output value and economic benefits of P1 treatment were also higher，which significantly increased by 16.5% and 20.9% over P0，and significantly increased by 8.6% and 11.3% of P3，respectively；（ 3） Higher potato tuber starch production，crude protein content and Vc level were detected in P1 treatment as well. The results also showed that，no significant differences in N，P and K contents，N and P accumulation amounts were found among different dosages of phosphate fertilizer. According to the comprehensive effects of considered treatments on yield，economic benefits and quality indices，45 kg（P2O5） /hm2 was the suitable application rate of phosphate fertilizer under the experiment conditions.