Fertilizer Effect Trial and Economic Benefits Analysis of Applying Potassium Fertilizer on Sweet Potato

The study aimed to ascertain the fertilizer effect of potassium fertilizer on sweet potato and its suitable dosage.In the fertilizer effect trial of potassium fertilizer on sweet potato in Yaxiao village,Mazhuang town,Qindu district in 2005～2006,6 treatments of applying 75,150,225,300,375 and 450 kg/hm2 potassium sulfate were set up,with applying no potassium fertilizer as CK.All the fertilizers as base fertilizers were applied for once in ridges in soil preparation and ridging in spring and the planting density was 7.20×104 plants/hm2.Compared with CK,the treatments applying potassium fertilizer increased 2 984.10～6 973.35 kg/hm2,increasing by 9.84%～22.98%.Under the condition of applying 165 kg/hm2 urea,750 kg/hm2 calcium superphosphate and 22 500 kg/hm2 organic fertilizer,the highest yield and the ratio of output to input of sweet potato applied with potassium sulfate fertilizer 217.50 kg/hm2 were 36 435.30 kg/hm2 and 12.99∶1 and that of sweet potato applied with potassium sulfate fertilizer 258.0 kg/hm2 were 36 417.6 kg/hm2 and 13.13∶1,whose economic benefit was best.Potassium sulfate fertilizer had significant increase effect on sweet potato and the optimum application amount of potassium sulfate fertilizer was 258.0 kg/hm2.