Growth and gas exchange of green manure plants under water stress

Abstract

Water stress alters the life cycle of plants, limiting their reproduction, productivity, and survival. Therefore, the search for species that are more tolerant to adverse environmental conditions is essential for environmental safety, considering soil health when using green manure plants. Therefore, this study aimed to investigate the effects of different levels of water stress on three green manure species, focusing on physiological responses and growth variables. The experiment was conducted in a greenhouse under a completely randomized design in a factorial scheme (3 x 3), with three plant species - T1 - jack bean (Canavalia ensiformis), T2 - pigeon pea (Cajanus cajan) e T3 - crotalaria (Crotalária juncea) and three field capacity levels (50%, 65% and 80%). Different behaviors were recorded for green manures in different water regimes, with significant differences observed in absolute growth rates, dry matter accumulation, stomatal conductance, transpiration, photosynthesis, and water use efficiency. Pigeon pea was the species that performed the highest photosynthetic efficiency in relation to the other cover crops, even under severe water regime conditions. However, jack bean was the most tolerant to the regime under water scarcity, responding with the best water use efficiency and dry matter accumulation among the green manures analyzed.