Soybean growth under stable versus peak salinity

Abstract

The production of soybean (Glycine max L.) has doubled in the last two decades. It is now being grown on both traditional arable lands and on marginal soils, including saline soils, in various parts of the world. Most research on crop tolerance to salinity has been performed using soils with stable levels of salinity. However, there are soils that undergo sudden increases in topsoil salinity for short periods of time. The aim of this study was to compare the effect of stable salinity concentrations with peaks of salinity for their effects on soybean vegetative growth, grain yield, and the accumulation of chlorides. The response of soybean growth was evaluated in pot experiments with the following treatments: Control (non saline soil), soil salinity level of 0.4 S m -1 (0.4S) or 0.8 S m -1 (0.8S), and soil subjected to salinity peaks of 0.4 S m -1 (0.4P) and 0.8 S m -1 (0.8P). The salinity levels were obtained by application of saline irrigation water. Soybean responded differently to stable salinity levels versus peaks of salinity. When salinity was a permanent stress factor, regardless of the salinity level (i.e. 0.4 and 0.8 S m -1 ), biomass production and differentiation of reproductive organs was greatly affected. For 0.8S treated plants, they never reached the reproductive phase. Conversely, only small differences in growth data were found between 0.4P and Control treatments, although an 80% decrease in yield was associated with the 0.4P treatment. To obtain a reasonable soybean yield, a leaf chloride concentration of 1 mg g -1 of Cl -in dry matter should be considered a maximum threshold. Key words: NaCl, Glycine Max L., saline irrigation, yield loss, chloride accumulationCrescimento da soja sob salinidade estável ou em forma de pulsos RESUMO: A produção de soja (Glycine max L.) duplicou nas últimas duas décadas. Atualmente está sendo cultivada em terras aráveis tanto nos solos tradicionais quanto marginais, incluindo solos salinos, em várias partes do mundo. A maioria das pesquisas sobre a tolerância das culturas à salinidade foi realizada utilizando solos com níveis estáveis de salinidade. No entanto, há solos que são sensíveis ao aumento brusco de salinidade do solo superficial por curtos períodos de tempo. Comparou-se o efeito das concentrações de salinidade estável com picos de salinidade no crescimento vegetativo da soja, na produção de grãos e no acúmulo de cloretos. A resposta do crescimento da soja à salinidade foi avaliada em experimentos em vasos com os seguintes tratamentos: irrigação com água destilada (Controle, C), a irrigação para alcançar a salinidade de 0,4 S m -1 (0,4S) ou 0,8 S m -1 (0,8S) e irrigação com picos para alcançar a salinidade 0,4 S m -1 (0,4P) e 0,8 Sm -1 (0.8P). A soja respondeu diferentemente aos níveis de salinidade estável contra picos de salinidade. Quando a salinidade foi um fator de estresse permanente, independentemente do nível de salinidade (ou seja, 0,4 e 0,8 S m -1 ), a produção da biomassa e a diferenciação dos órgãos reprodutivos foram muito afetadas,...

Soybean Response and Ion Accumulation Under Sprinkler Irrigation With Sodium-Rich Saline Water

“…Since Na + and Cl − are known to be absorbed by leaves (Maas et al, 1982), high levels of these toxic ions were expected to be found in aerial tissue, especially leaves. Leaf chloride values obtained in this research (1 to 6 mg g −1 DM) were higher than those found in previous studies, ranging from 0.13 to 4.45 mg g −1 DM (Bustingorri and Lavado, 2011;Essa, 2002;Jeong-Dong et al, 2008) where salinity was applied to plant roots, either by soil salinity or hydroponic. The proportional increase in leaf Cl − and Na + concentration found in this experiment are within the range reported by Grieve et al (2003).…”

“…The obtained results are consistent with results from other authors showing TABLE 4 Linear regression models for all sampling dates. Y: soybean grain yield (g dry matter plant −1 ); CL: leaf chloride concentration (mg g −1 dry matter); K/NA: Leaf K + /Na + concentration ratio soybean's low tolerance for salts, in this case 2 dS m −1 This EC value is half the one determined as a threshold for soybean under flood, furrow or drip irrigation systems found either in early research (Maas, 1986;Maas and Hoffman, 1977) as well as in recent studies (Bustingorri and Lavado, 2011;Chang et al, 1994;Katerji et al, 2003;Kao et al, 2006;Shalhevet et al, 1995). Saline sprinkler irrigation had a more severe effect on reproductive organs than on vegetative ones, which has not been reported in previous studies.…”

Crescimento de leguminosas utilizadas na adubação verde em diferentes níveis de sais na água de irrigação

“…A tolerância à salinidade é variável entre espécies (Kudo et al, 2010) e até mesmo dentro da espécie (Mendonça et al, 2007;Zhu et al, 2008) e depende de diversos fatores, como estádio fenológico (Bustingorri & Lavado, 2011), intensidade e duração do estresse salino (Neves et al, 2009). …”

Quinoa (Chenopodium quinoa Willd.) versus soja (Glycine max [L.] Merr.) en la nutrición humana: revisión sobre las características agroecológicas, de composición y tecnológicas

“…La quinoa ha mostrado una plasticidad para la tolerancia y/o resistencia al incremento del estrés salino y a la disminución de la disponibilidad del agua mayor que la soja 27 . La quinoa ha permitido mayores niveles de salinidad (solución salina con conductividad eléctrica máximo 52dS/m para quinoa 28 frente a 8,0dS/m para soja 29 ), ocasionando un bajo impacto en los rendimientos del grano 19,[30][31][32] , a diferencia de la significativa reducción que se ha observado en los granos de soja debido a la disminución del contenido de clorofila y de la actividad del fotosistema II 33 . El favorable comportamiento de la quinoa ha sido explicado a través de la respuesta de sus estomas al cierre y del eficiente sistema que posee para realizar ajustes osmóticos importantes para el mantenimiento de la turgencia de la hoja que la muestran insensible a las sequías y a cambios abruptos de salinidad.…”