Effect of soil management on water deficit, gas exchange and cowpea yield in the semi-arid region

Abstract

Efeito de manejos do solo no déficit hídrico, trocas gasosas e rendimento do feijão-de-corda no semiárido 1Effect of soil management on water deficit, gas exchange and cowpea yield in the semi-arid region T-P, solo mobilizado somente pela enxada; T-ESC, solo escarificado a 0,30 m; T-CS, solo com subsolagem e captação in situ; o T-CCM, subsolagem, captação in situ e cobertura morta e o T-CCO, com subsolagem, captação in situ, cobertura morta e compostagem. Os resultados mostraram que a interação das práticas da cobertura morta, compostagem, subsolagem e a técnica de captação in situ, dotaram o T-CCO de maior capacidade de captar e armazenar água no solo, com um consequente aumento da disponibilidade hídrica para as culturas. Tal fato aumentou o rendimento da T-CCO em relação aos demais tratamentos na ordem (1º ao 4º) de 41%, 28%, 47% e 12%. Para um déficit hídrico gerado por 10 dias consecutivos sem chuvas, o T-CCO apresentou os melhores resultados na manutenção do estado fisiológico das plantas. No entanto, quando o solo se encontra próximo à capacidade de campo, as práticas de manejo do solo não mostraram diferenças significativas na condutância estomática, fotossíntese, transpiração e na temperatura foliar. Tal fato expressa a importância do manejo do solo em condições limitantes de umidade. Palavras-chave:Vigna unguiculata. Solos-manejo. Plantio de sequeiro. Estresse hídrico.ABSTRACT -Rainfall variability in semi-arid areas often results in water shortages during the cycle of the cowpea (Vigna unguiculata (L.) Walp.), affecting yield. This study aimed to investigate the effect of different management practices on soil water deficit, leaf gas exchange and the yield of the cowpea under rainfed conditions in a semi-arid region. The experimental design was completely randomised into split lots of five management systems (treatments) and two layers of soil (0.15 and 0.30 m), with four replications. The management systems investigated were: T-P, soil turned by hoe only; T-ESC, ploughing to 0.30 m only; T-CS, soil with subsoiling and in situ catchment; T-CCM, subsoiling, in situ catchment and mulch, and T-CCO, subsoiling, in situ catchment, mulch and compost. The results showed that the interaction of the practices of mulching, composting, subsoiling and in situ catchment, resulted in the T-CCO having a greater capacity to capture and store water in the soil, with a consequent increase in water availability for the crops. This fact increased the yield of T-CCO in relation to the other treatments by (1st to 4th) 41%, 28%, 47% and 12%. For a water deficit generated after ten consecutive days without rain, the T-CCO displayed the best results in maintaining the physiological state of the plants. However, when the soil was close to field capacity, there were no significant differences for soil management practice in stomatal conductance, photosynthesis, transpiration or leaf temperature. This fact demonstrates the importance of soil management under limiting conditions of moisture.

Physiological responses of Urochloa ruziziensis inoculated with Azospirillum brasilense to severe drought and rehydration conditions

“…In other grasses there are reports that the RWC gradually decreases, as shown in wheat (Santos et al, 2012) and barley (Thameur et al, 2012), attributed to the improvement process (Sherrard et al 2009;Souza et al 2014), being the photosynthetic rate, stomatal conductance and transpiration, changes that firstly respond to water deficiency.Stomatal conductance presents variation more rapidly with the reduction of water available in the soil, as observed in several studies independent from the photosynthetic physiology of plants, reported for C 3 (Santos et al, 2012;Yousfi et al, 2012;Fernandes et al, 2015) and C 4 plants (Hu et al, 2010;(Mattos et al, 2005;Hu et al, 2010;Zhou et al, 2013). In the present study, this condition also occurs being observed the reduction of gs (Fig.3a).…”

“…These values are close soybean (Casaroli et al, 2007) and bean (Fernandes et al, 2015), before the reproductive stages.…”

Physiological tolerance to drought under high temperature in soybean cultivars

“…Water deficit promotes the reduction of leaf water potential, leading to stomatal closure, decreased CO 2 absorption, and reduced photosynthesis (Goisser et al, 2016;Batista et al, 2018;Moura et al, 2018). In addition, water deficit increases foliar temperature (Heschel et al, 2014), affects membrane properties, and decreases dry matter production, leading to premature senescence and causing reduced production (Arruda et al, 2015;Fernandes et al, 2015). High temperature combined with water deficits has been a frequent phenomenon due to the global warming (Gondim et al, 2010;Lubovská et al, 2014;Perdomo et al, 2017).…”

Efeito do déficit hídrico na fase de enchimento de grãos do feijoeiro comum

“…Segundo Fernandes et al (2015) em ambientes com menores conteúdos de água disponível no solo, as plantas reduzem a condutância estomática com consequências nas taxas de transpiração e fotossíntese, responsáveis pelo desenvolvimento do vegetal. Para Olsovska et al (2016), a ocorrência de déficit hídrico no solo associada a incidência de outros fatores abióticos, como temperatura alta, baixa umidade relativa do ar ou luz intensa, aumenta a fotoinibição da fotossíntese.…”