Gas exchange dynamics and leaf water potential in sorghum intercropped with prickly pear and irrigated with reused water

Abstract

The reuse of treated domestic wastewater is a promising alternative in semiarid regions of the world. This study aimed to assess the intercropping of sorghum (Sorghum sudanense) with prickly pear (Opuntia stricta) cultivated under irrigation depths (80, 100 and 120 % of the crop evapotranspiration - ETc) with reused water, in soil with and without mulch. A randomized block design was used, in a 3 (irrigation depths) x 2 (with and without mulch) factorial scheme, with four replications. The leaf gas exchange, water potential and chlorophyll fluorescence were assessed. The use of mulch in the intercropping between prickly pear and sorghum positively influenced the gas exchange and photosynthetic efficiency, resulting in increases of up to 156, 186 and 14 %, respectively for net photosynthesis, transpiration and photosynthetic efficiency, in addition to increasing the water potential. The irrigation depths affected the quantum yield and water potential, with the 100 % irrigation depth standing out. Considering the performance of the physiological variables, it is possible to indicate as positive the adoption of reused water and mulch.

KEYWORDS: Sorghum sudanense, Opuntia stricta, abiotic stress, domestic wastewater.