Soil moisture tension as an alternative for improving sustainable use of irrigation water for habanero chilies (Capsicum chinense Jacq.)

Abstract

During 2015 and 2016, two experiments were conducted under contrasting climatic conditions (rainy and dry seasons, respectively) in Campeche, Mexico, to test various thresholds (treatments) of soil moisture tension for the beginning of irrigation, and their effect on the yield and quality of Habanero Chilies, and also on the efficiency of water use, the virtual water content and its blue and green components. In both experiments, irrigation was initiated when the soil moisture tension, measured at 30 cm depth, took the values −10, −40 and −70 kPa, considered as treatments, using producer irrigation management as a control. The number of fruits per plant (NFP), fruit weight per plant (FWP), fruit diameter (FD), fruit length (FL), yield (Y), total water use efficiency (TWUE), irrigation water use efficiency (IWUE), virtual water (VW), green virtual water (GVW), and blue virtual water (BVW) were determined and statistically analyzed. During 2015, rains masked treatment effects, although significant effects were detected for FL, IWUE, VW and BVW. In 2016, the different irrigation treatments during the dry season had significant effects on the variables NFP, FWP and Y, with statistically higher values in the −10 kPa treatment; and also in IWUE, GVW and BVW with statistically higher values in the −70 kPa, −40 kPa and the control treatments, respectively. Nearly all crop growth and yield related variables had higher values with lower soil moisture tension. In both production cycles, significantly lowest values for IWUE and significantly highest values for BVW were obtained under producer irrigation management (controls); whereas significantly highest values were recorded for IWUE and significantly lowest for BVW in the −40 and −70 kPa treatments. It was concluded that the use of tensiometers to define the beginning of irrigation allows for improving irrigation sustainability.