[Present fertilization and the potential of high yield on watermelon in Jiangsu Province, China.]

Watermelon fertilization in main planting regions of Jiangsu Province was investigated in order to evaluate the characteristics of efficient fertilization and improve the yield and quality of watermelon. The investigation was performed in Dongtai, Dafeng, Sihong, Pizhou and Donghai. The results showed that the average yield of watermelon in Jiangsu Province was 48325 kg·hm-2, and the highest yield was 97500 kg·hm-2. The watermelon yield was improved by straw return of 14-15 t·hm-2. The watermelon yield was increased with the increase of organic manure application under the quantity of 30 t·hm-2, while it trended to decrease when the manure application exceeded 30 t·hm-2. The peasant households of efficient high yield and inefficient high yield on organic manure were 16.5% and 29.1%, respectively. The peasant households of efficient high yield and inefficient high yield on total nitrogen fertilizer were 14.9% and 26.3%, while those on chemical nitrogen fertilizer were 19.6% and 22.4%, respectively. The peasant households of efficient high yield and inefficient high yield on total phosphorus fertilizer were 20.9% and 21.8%, while those on chemical phosphorus fertilizer were 13.7% and 29.5%, respectively. The peasant households of efficient high yield and inefficient high yield on total potassium fertilizer were 14.9% and 26.3%, while those on chemical potassium fertilizer were 29.6% and 12.2%, respectively. Compared to basic application, basic and top application combination enhanced the watermelon yield, so did the foliar fertilization. It was suggested that the peasant households of inefficient high yield and inefficient low yield should decrease the fertilization quantity to improve fertilizer efficiency, while those of efficient low yield should regulate nutrient components and fertilization stage.