Optimization of time and method of potassium application to potato (Solanum tuberosum L.) crop on sandy clay loam soil

Adequate supply of potassium (K) has a crucial role in higher productivity of potato (Solanum tuberosum L.) tubers because it plays an important role to maintain tone, vigor and efficiency of the plant. However, time and method of K application may have different effects on growth and yield of potato owing to different availability to the plant. Field studies were conducted during 2006-7 and 2007-8 on sandy clay loam soil to evaluate the effects of time and methods of K fertilizer application on potato yield and quality. The nine treatments consisted of T0: Control, T1: Full dose at planting through broadcast method, T2: Full dose at planting through placement method, T3: Full dose 30 DAP (DAP = Days after planting) through broadcast method, T4: Full dose 30 DAP through placement method, T5: % dose at planting + 1/2 30 DAP through broadcast method, T6: 1/2 dose at planting + 1/2 30 DAP through placement method, T7: 1/2 dose 30 DAP + 1/2 60 DAP through broadcast method, T8: 1/2 dose 30 DAP + 1/2 60 DAP through placement method were arranged according to randomized complete block design with three replications. Results revealed that potato growth and yield were markedly influenced by the time and application technique of K fertilizer. Among different treatments, full K application at planting through placement technique was found superior in term, of total emergence percentage, number of tubers per plant, number of leaves per plant, plant height, tuber weight per plant, yield per ha, TSS, specific gravity and tuber dry matter percentage followed by 1/2 dose at planting + 1/2 30 DAP through placement method. The treatments where 1/2 dose 30 DAP + 1/2 60 DAP through broadcast and placement methods produced lowest tuber yield while all other treatments showed mixed response. The study suggested the need to apply K fertilizer at the time of planting through placement technique to maintain higher potato yield and quality.