The Effects Of Potassium Applied at Different Doses and Times on The Yield and Nutrient Content of Pumpkin Seed (Cucurbita pepo L.)

Potassium is an important nutrient in plant yield and fruit quality. Significant yield losses and quality defects can be seen in potassium deficiency. For this purpose, it was tried to examine the yield and yield parameters of potassium applied at different concentrations and from different sources, the yield and yield parameters of the pumpkin seed plant, and the changes in the leaf and grain nutrient content. In this study carried out in field conditions, After planting, 3 different sources of potassium fertilizer were used as potassium sulfate, potassium nitrate and potassium chloride at 0, 10 and 20 kg da⁻¹ K₂O. The second different application was applied 40 days before the harvest with 3 different sources of potassium fertilizer as potassium sulfate, potassium nitrate and potassium chloride at 0, 2 and 4 kg da⁻¹ K₂O from the leaf. This application is given in 2 parts. The first application was applied 40 days before the harvest, the second application was applied 15 days before the harvest. At the end of the plant vegetation period, the plants were harvested and the seeds in the fruit were removed. In this study, as a result of potassium fertilizer applications, statistically significant increases occurred in yield and nutrient content compared to the control group. The highest seed grain yield was obtained from 20 kg/da application of potassium sulfate (279.0 kg da⁻¹) after sowing. The lowest seed grain yield was obtained from the control group (151.0 kg da⁻¹). The highest grain potassium content was obtained with the application of potassium sulfate at 2 kg da⁻¹ before 40 days harvest (8400 mg kg⁻¹). As a result of the PCA analysis, it was seen that especially potassium sulfate and potassium nitrate were applied to the pumpkin plant, resulting in a significant increase in yield. It is recommended to test the effectiveness of these results by applying them in different soil conditions and climatic regions.