Efeito da inoculação do Bacillus aryabhattai na mitigação do déficit hídrico em feijão-caupi (Vigna unguiculata L. Walp.)

Abstract

Cowpea is a crop of great socioeconomic importance, especially in semi-arid regions subject to irregular rainfall, where water stress is one of the main factors limiting plant growth and productivity. In this context, the use of bioinputs emerges as a sustainable alternative to mitigate the effects of water deficiency. This study aimed to evaluate the effects of different irrigation depths and seed inoculation with Bacillus aryabhattai on the growth and yield of cowpea plants. The experiment was conducted in a completely randomized design (CRD) with a 2 × 4 factorial arrangement, consisting of two seed treatments (with and without B. aryabhattai) and four soil moisture levels based on the soil water-holding capacity (40, 50, 65, and 80%), with eight replications, totaling 64 experimental units. Biometric, physiological, and yield-related parameters were evaluated. The results showed that water stress impaired plant development and yield, with more pronounced reductions under the most restrictive irrigation levels. An interaction between water availability and microbial inoculation was observed only for leaf dry mass, root dry mass, and total grain weight. In addition, plants inoculated with B. aryabhattai required a lower volume of water throughout the crop cycle compared to non-inoculated plants, indicating greater water use efficiency. It is concluded that water stress negatively affects cowpea performance, whereas inoculation with B. aryabhattai showed specific effects, indicating that further studies are needed to confirm the potential of this bioinput to mitigate water stress in cowpea plants.