Optimization of New Generation Potassium (Ng-K) Fertilizer for Improvement in Quantity and Quality of Citrus (Citrus Limon)

Abstract

Potassium (K) performs multiple essential functions in the plant, including enzyme activation and osmotic regulation. Citrus fruit quality gains considerable influence from potassium (K) fertilizer rate, application method, and sources used. The conducted field experiment assessed the impact and response of different levels of K applications on the quality and yield parameters of citrus fruit, determining a suitable time, stage, and K fertilizer dose for citrus trees. Comparing traditional K fertilizer, i.e., sulfate of potash (SOP), with new-generation potassium (NG-K) employed the use of foliar and soil (basal) applications. Treatments included (i) T1: Control (0 NPK), (ii) T2: Recommended NP and without K, (iii) T3: 500 g K as sulfate of potash (SOP) (basal), (iv) T4: New generation K (NG-K) fertilizer @1.5% (foliar), and (v) T5: 400 g NG-K fertilizer (basal). Observations revealed that citrus trees responded positively in growth characteristics, including fruit quality and physiological attributes, under both foliar and basal K fertilizer applications of different K sources. Notably, NG-K fertilizer proved a better source of K, whether applied as a basal dose or foliar spray. For growth characteristics like the fresh weight of leaves and fruit mass, obtaining the highest values of 35.2 and 172 g, respectively, resulted when applying a basal dose of NG-K. On the other hand, maximum total sugar content (13 mg L-1) and juice content (40%) occurred under foliar-applied NG-K. Foliar application of K fertilizer proved to be more effective for better growth and fruit quality parameters than the basal application of SOP.