| The experiment was conducted to find the approaches of realizing high yield of onion by optimizing transplanting time, density and fertilizer application.The results showed that, in the central region of Gansu Province, the transplanting time, plant density and potassium application amount were the primary factors that restricted the yield of onion.Moderate advancing the transplanting time could increase the yield of onion.However, when seedlings were transplanted too early, the ratios of seedling survival and sprouting would be increased, and consequently, the yield was influenced;when the seedlings were transplanted too late, the harvesting time would be delayed.The optimal transplanting date, plant density and K2O application amount of plastic mulched onion were March 10th to 15th, 29 300 plants/667m2 and 13.3～17.5 kg/667m2, respectively.With the above integrated measures, the onion yield could be raised to more than 8 000 kg/667m2. |