Potassium transport and use efficiency for sustainable fertigation in protected cropping

The increasing demand for high-quality horticultural produces in global markets has driven the growing crop production under protected cropping, which are usually more efficient in fertilizer use compared to field cultivation. As one of the key macronutrients, available potassium (K+) resources have decreased due to the expansion of intensive agriculture and excessive use of K fertilizers. Currently, limited strategies have been adopted to improve crop quality in protected cropping with sustainable use of K+ fertigation and its comprehensive understanding at physiological and molecular levels. Therefore, we highlight the importance of optimal use of K+ in fertigation in protected cultivation that may also enhance crop quality characteristics. We review different K+ channels and transporters from various protein families responsible for K+ absorption and distribution across different plant tissues. An analysis of the literature on transcriptome, ionome, proteome and metabolome profiles of crops suggests the crucial roles of K+ in maintaining ion homoeostasis and modulating stress responses. It reveals that optimal K+ fertigation levels in protected cropping not only aids in maintaining the overall crop growth and production but also participates in maintaining the fruit quality. This review can potentially guide crop production and resource use efficiency in protected cropping, contributing to global food security and a better sustainable agricultural and environmental future.