Effect of water availability on growth and water use efficiency for biomass and gel production in Aloe Vera (Aloe barbadensis M.)

Abstract

The cultivation of Aloe Vera (Aloe barbadensis Miller) has achieved economic importance due to the products which are obtained from its leaves. However, there is a scarcity of information about its agronomic management and the effect of water availability for its establishment and production. The objective of this study was to evaluate the effect of different irrigation rates on the growth and water use efficiency (WUE) for the production of leaves biomass and gel. We applied four irrigation treatments calculated to be 20, 15, 10 and 5% of the mean evaporative demand (ETo) of last year, equivalent 4 L h−1 during 60, 45, 30 and 15 min (8, 6, 4 and 2 L h−1, respectively), designated as T1, T2, T3 and T4. Plants submitted to the low water availability (T4) produced less new leaves and plantlets per plant. The greatest number of new leaves was produced by the plants T1 and the greatest number of plantlets in an intermediate treatment (T2). The extreme treatments (T1 and T4) had lower values of WUE (10.8 and 10.9 g leaf biomass L−1 water) than the intermediate treatments T2 and T3 (24.5 and 15.6 g leaves biomass L−1 water). The WUE values for gel production were 8.6, 17.1, 13.1 and 6.8 g L−1 in T1, T2, T3 and T4; the T2 plants were the most efficient. The precise water requirement under this edapho-climatic condition was obtained. This requirement, based on the interaction among the metabolic pathway, atmospheric evaporative demand and soil water dynamics, was 15% of the reference evapotranspiration. This condition gave the maximum aerial biomass and gel production for unit of water utilized, and thus the greatest water use efficiency for Aloe Vera.