Effects of irrigation thresholds and temporal distribution on potato yield and water productivity in sandy soil

Water productivity enhancement in farming systems is one of the most critical challenges facing the agricultural sector in the twenty-first century. Precision irrigation based on soil matric potential (SMP) measurements effectively enhances water productivity. However, the temporal effect of an SMP-based comfort zone on potato crops is lacking. This paper evaluates the temporal effect of a range of soil matric potential thresholds (namely, −7, −10, −15, −18, −21, −24, −30, and −45 kPa) in a sandy soil on the marketable yield and irrigation water productivity (WP) of potato grown in containers in a greenhouse with the Partial Least Square algorithm (PLS) and a mixed model. The results of this study suggest that a comfort zone maximizing potato yield is located between − 10 and − 24 kPa. The − 24 kPa threshold generated the highest yield while reducing the irrigation water use up to 47% and generating the highest WP. The average yield in the comfort zone reached 496.4 g per plant, an increase of 88% over the lowest yield achieved at an SMP of –45 kPa. In addition, the leaf expansion and tuber initiation physiological stages are the most important periods where the daily SMP had the most influence on the marketable yield. This information will assist potato growers in maintaining high yields while optimizing their use of irrigation water.