Root Water Uptake of Pepper Plants Under Deficit Irrigation System.

Root water uptake is a component of water balance that should be more clearly understood. This study was carried out in a completely randomized design with three replications under the greenhouse condition in Shahrekord University, Shahrekord, Iran. In this study, evaluation of the pepper plant root water uptake (RWU) affected by irrigation water was investigated. Irrigation treatments included control (full irrigation level, FI) and three deficit irrigation levels, 80, 60, and 40% of the plant^’s water requirement called DI₈₀, DI₆₀ and DI₄₀, respectively. A bare soil surface (no plant cover) treatment was used to measure evaporation from the soil surface. Daily measurements of volumetric soil moisture (VSM) were made at each 10 cm intervals of the soil column, considered as a layer. The differences between the measured VSM and the VSM in the next day, and also the evaporation rate at the soil surface at the same layer of the control (bare soil) treatment were calculated and eventually the value of RWU in each layer per day was estimated. The results showed that the maximum and the minimum RWUs were found in the FI and the DI₄₀, respectively. The averages of root water uptakes (ARWUs) in DI₈₀, DI₆₀, and DI₄₀ were reduced by 17.1, 48.8, and 68.3%, respectively. Also, in treatment DI₈₀, the reduced rate of uptake was less than the reduced rate of plant's applied water.