Effects of potassium application on vegetative growth, fruiting, and nutrient status of Kinnow mandarin under Indian sub-tropical conditions

Abstract

Kinnow mandarin is the predominant citrus crop of Punjab state. The area and production of Kinnow are increasing in the southern–western districts of the state because of its high adaptability, yield potential, and better fruit quality, which ensure higher economic returns to the growers. However, soils of sub-mountain and in some areas of central zones of Punjab are deficient in potassium which hinders the quality and production of Kinnow in these regions. Considering these facts, the present study was undertaken during 2009–2020 to find out the optimum level of potassium fertilization in addition to recommended doses of nitrogen and phosphorous required under sub-mountain and central zones of Punjab. The results showed that soil application of potassium significantly increased the plant height, spread, and canopy volume. Fruit weight, fruit number, yield, TSS, and TSS/acid ratio were also markedly improved with soil application of potassium. Leaf analysis revealed that nutrient uptake like N, K, Mg, Fe, and Cu increased with increased soil K application. However, P, S, Mn, and B did not show any linear trend with an increase in the K application. The results indicated that all rates of K application improved fruit quality and yield in Kinnow. So, it is recommended that soil application of K100 and other recommended doses of nitrogen (N100) and phosphorous (P50) should be made to enhance fruit yield and quality in Kinnow mandarin under sub-mountain and central zones of Punjab state.