Physiological response of a pepper (Capsicum annuum L.) crop to different trickle irrigation rates

Abstract

The present field study was conducted to analyse the physiological response of a pepper (Capsicum annuum L.) cropto different trickle irrigation rates, by means of periodical measurements of leaf water potential (leaf) and stomatal resistance(Rs) at predawn during the plant growth cycle and at different times of the day during the fruit-growing stage,from predawn to nightfall. The internal water status of the plants was related to their growth rate (measured as aerialdry matter and leaf area index) and yield (marketable and total). The different irrigation rates tested were determinedaccording to the crop irrigation requirements (IR) calculated on the basis of crop evapotranspiration (ETc). Four treatmentswere established: 1.25 IR, 1.00 IR, 0.75 IR and 0.50 IR. Irrigation water amounts between 75 and 125% IR didnot cause important variations in growth and yield parameters, although a severe water deficit did induce a continuousadaptation of the plants by reducing their size (reflected by less dry matter accumulation and leaf area) and consequentlytheir yield. However, there were small differences between treatments in the measurements of leaf and Rs, which indicatesthat crop growth was more affected by severe water deficits than these two parameters in pepper crops with dailytrickle irrigation. leaf did not justify the mechanisms of stomatal regulation, even on hot and dry middays.