Leaching fraction impacts water use efficiency and nutrient losses in maize crop under salt stress /Fração de lixiviação impacta uso efficiente da água e perdas de nutrientes em milho sob estresse salino

HIGHLIGHTS: Salinity reduces nutrient absorption regardless of the leaching fraction. The leaching fraction determined by the Rhoades method reduces water use efficiency. A leaching fraction of 0.15 according to soil water balance reduces nutrient losses. Although leaching fraction (LF) is used to r...

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Published in:Revista brasileira de engenharia agrícola e ambiental 2022-11, Vol.26 (11), p.797
Main Authors: Freitas, Emanuel D, Lacerda, Claudivan F. de, Amorim, Aiala V, Ferreira, Jorge F. da S, Costa, Carlos A. G, Silva, Alexsandro O. da, Gheyi, Hans R
Format: Article
Language:English
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Summary:HIGHLIGHTS: Salinity reduces nutrient absorption regardless of the leaching fraction. The leaching fraction determined by the Rhoades method reduces water use efficiency. A leaching fraction of 0.15 according to soil water balance reduces nutrient losses. Although leaching fraction (LF) is used to remove salts from the root zone under conditions of salinity, if miscalculated, it can decrease water use efficiency and lead to major losses of essential nutrients. This study evaluated the water use efficiency, leaf nutrient concentrations in maize plants, and nutrient losses as a function of two ways of determining the LF in maize crop grown in soil columns under salt stress. The experimental design used was completely randomized, with treatments arranged in split plots, with seven replicates. The plots were formed by two methods of determination of LF, and the subplots by four electrical conductivities of irrigation water--[EC.sub.w] (0.5, 2.0, 4.0, and 6.0 dS [m.sup.-1]). The leaching fractions were established according to 1) the formula proposed by Rhoades (RHO) and 2) by applying a LF of 0.15 calculated according to the soil water balance (SWB). The leaf concentrations of N, P, Ca, and Mg were higher in plants under SWB than under RHO method. The leaf concentrations of N, P, and K decreased with increased salinity, regardless of the LF. Adding a LF of 0.15 according to SWB resulted in decreased losses of nutrients and higher physical water productivity, as compared to the RHO. Thus, a more precise determination of the LF is needed to increase economic returns for maize cultivation in semi-arid regions when using brackish water for irrigation. Key words: Zea mays L., salt stress, leaching of nutrients, water productivity Embora a fração de lixiviação (FL) seja utilizada para remover sais da zona radicular em condições de salinidade, quando inadequadamente calculada, pode diminuir a eficiência do uso da água e levar a grandes perdas de nutrientes essenciais. No presente estudo avaliou-se o uso da água, as concentrações de nutrientes foliares em plantas de milho e as perdas de nutrientes em função de duas formas de determinação da FL em plantas de milho cultivadas em colunas de solo sob estresse salino. O delineamento experimental utilizado foi o inteiramente casualizado, com os tratamentos dispostos em parcelas subdivididas, com sete repetições. As parcelas foram formadas por duas formas de determinação da FL e as subparcelas por quatro condutividades elétr
ISSN:1415-4366
1807-1929
DOI:10.1590/1807-1929/agriambi.v26n11p797-806