The use of plant-growth-promoting rhizobacteria (PGPR) can be one option for mitigating the impact of abiotic constraints on different cropping systems in the tropical semi-arid region. Studies suggest that these bacteria have mechanisms to mitigate the effects of water stress and to promote more significant growth in plant species. These mechanisms involve phenotypic changes in growth, water conservation, plant cell protection, and damage restoration through the integration of phytohormone modulation, stress-induced enzyme apparatus, and metabolites. The aim of this study was to evaluate the growth, leaf gas exchange, and yield in maize (Zea mays L.—BRS Caatingueiro) inoculated with Bacillus aryabhattai and subjected to water and salt stress. The experiment followed a randomised block design, in a split-plot arrangement, with six repetitions. The plots comprised two levels of electrical conductivity of the irrigation water (0.3 dS m⁻¹ and 3.0 dS m⁻¹); the subplots consisted of three irrigation depths (50%, 75%, and 100% of the crop evapotranspiration (ETc)); while the sub-subplots included the presence or absence of B. aryabhattai inoculant. A water deficit of 50% of the ETc resulted in the principal negative effects on growth, reducing the leaf area and stem diameter. The use of B. aryabhattai mitigated salt stress and promoted better leaf gas exchange by increasing the CO₂ assimilation rate, stomatal conductance, and internal CO₂ concentration. However, irrigation with brackish water (3.0 dS m⁻¹) reduced the instantaneous water-use efficiency of the maize. Our results showed that inoculation wiht PGPR mitigates the effect of abiotic stress (salt and water) in maize plants, making it an option in regions with a scarcity of low-salinity water.

Semi-arid regions present the inherent problem of accumulation of salts in the soil due to the use of brackish water for irrigation, and water deficit compromises the growth and physiological indices of crops. This study evaluated the effect of salt and water stress on growth and gas exchange in the zucchini cv. Caserta crop. The study was conducted at the University of International Integration of Afro-Brazilian Lusophony, Redenção, Ceará State, Brazil. The experimental design was completely randomized, in a 5 × 2 factorial scheme with five levels of electrical conductivity of the irrigation water - ECw (0.5, 1.0, 1.5, 2.0, and 2.5 dS m-1) and two water regimes (50 and 100% of the potential crop evapotranspiration - ETc), with five replicates. At 36 days after sowing, the following traits were evaluated: CO2 assimilation rate, transpiration, stomatal conductance, internal carbon concentration, leaf temperature, relative chlorophyll index, and water use efficiency. At 45 days after sowing, the plant height, stem diameter, number of leaves, and leaf area were also evaluated. The use of brackish water (1 to 2.5 dS m-1) reduced the growth parameters of zucchini cv. Caserta. The increase in ECw caused a decline in the physiological traits. Under 100% ETc, higher values of CO2 assimilation rate, transpiration, and instantaneous water use efficiency were recorded, and there was 50% ETc for internal carbon concentration, even with the increase in ECw.

Irrigation with saline water affects the agronomic performance of the maize crop; however, the use of vegetal mulch may mitigate salt stress and promote an increase in yield. In this way, this study aimed to evaluate the grain yield of the maize plants submitted to different water salinity levels in the presence and absence of mulch. The experiment was conducted in a randomized block design arranged in a 2 × 2 factorial scheme. The first factor was the salinity of the irrigation water (1.0 and 4.0 dS m-1) and the second, with and without mulch, and five replicates. The variables analyzed were: unhusked ear mass, husked ear mass, cob mass, straw mass, husked ear diameter, husked ear length, and yield. The irrigation water with higher electrical conductivity affects negatively the ear mass with and without straw, ear diameter and ear length. The use of vegetation cover on the soil increased the unhusked ear mass with and without straw, ear diameter and length. The water with higher salinity (4.0 dS m-1) reduces the maize grain yield but with less intensity in the presence of mulch.

HIGHLIGHTS Salt water reduces gas exchange in the okra crop, but organomineral fertilization mitigates these effects. The use of organic and mineral fertilization is viable in okra crops under salt stress. Organic fertilizer (100% bovine biofertilizer) decreases internal CO2 concentration.

PRODUTIVIDADE DA CULTURA DO AMENDOIM SOB DIFERENTES SUPRESSÕES DA IRRIGAÇÃO COM ÁGUA SALINA GEOVANA FERREIRA GOES1; GEOCLEBER GOMES DE SOUSA2; SAMUEL DE OLIVEIRA SANTOS1; FRANCISCO BARROSO DA SILVA JUNIOR3; EMANUEL D’ ARAÚJO RIBEIRO DE CEITA4 E KELLY NASCIMENTO LEITE5 1 Graduandos no curso de Agronomia da Universidade da Integração Internacional da Lusofonia Afro-Brasileira (Avenida da Abolição, 3, centro, 62.790-000, Redenção/Ce, Brasil). E-mails: ggoes64@gmail.com; samueloliveira1111@gmail.com. 2 Prof. Doutor, Instituto de Desenvolvimento Rural, Universidade da Integração Internacional da Lusofonia Afro-Brasileira (Avenida da Abolição, 3, centro, 62.790-000, Redenção/Ce, Brasil). E-mail:sousagg@unilab.edu.br. 3Mestrando pelo Programa de Pós-graduação em Ciência do Solo da Universidade Federal do Ceará, Campus do Pici (Avenida Mister Hull, 2977, Pici, 60.021-970, Fortaleza/Ce, Brasil) Email: juniorbarroso99@hotmail.com. 4Mestrando pelo Programa de Pós-graduação em Agronomia (Ciência do Solo) da Faculdade de Ciências Agrárias e Veterinárias (Rua: Prof. Paulo Donato Castellane, SN, 14.004-900, Jaboticabal/SP, Brasil) E-mail: emanuelceita@hotmail.com. 5Prof. Doutora, Centro Multidisciplinar da Universidade Federal do Acre, Campus Floresta (Rua Estrada da Canela Fina, KM 12 Gleba Formoso - São Francisco, 69.895-000, Cruzeiro do Sul/AC). E-mail: knleite.ufac@gmail.com. 1 RESUMO O déficit hídrico associada ao estresse salino afetam a produtividade das culturas agrícolas. Objetivou-se avaliar a produtividade da cultura de amendoim irrigado com água de baixa e alta salinidade submetida a diferentes intervalos de supressão. O experimento foi conduzido em condições de campo, no período de agosto a outubro de 2019 na Fazenda Experimental de Piroás, Redenção-CE. O delineamento experimental utilizado foi o de blocos ao acaso em arranjo fatorial, sendo o primeiro fator a salinidade das águas de irrigação (1,0 e 4,0 dS m-¹) e o segundo fator, quatro intervalos de supressões (IS1= 40 a 55 DAS; IS2 = 55 a 70 DAS; IS3 = 70 a 85 DAS e IS4 = sem intervalos de supressão), com quatro repetições. Foram avaliadas as seguintes variáveis: número, massa, comprimento e diâmetro de vagem e a produtividade. O tratamento sem intervalo de supressão hídrica associado a água de menor salinidade proporcionam maior número e diâmetro de vagem. A água de maior salinidade afeta a massa e comprimento de vagem. A utilização da água de maior ou menor salinidade sem intervalo de supressão da irrigação proporciona maior produtividade da cultura do amendoim. PALAVRAS CHAVES: Arachis hypogaea L., déficit hídrico, estresse salino GOES, G. F.; SOUSA, G. G.; SANTOS, S. O.; SILVA JUNIOR, F. B.; CEITA, E. A. R.; LEITE, K. N.PEANUT CULTURE YIELD UNDER DIFFERENT SALT WATER IRRIGATION SUPPRESSIONS 2 ABSTRACT The water deficit associated with salt stress affects the productivity of agricultural crops. The objective was to evaluate the productivity of peanut culture irrigated with low and high salinity water submitted to different suppression intervals. The experiment was conducted under field conditions, from August to October 2019 at the Experimental Farm of Piroás, Redenção-CE. The experimental design used for the randomized blocks in a factorial arrangement, with the first factor is the salinity of the irrigation water (1.0 and 4.0 dS m-¹) and the second factor, four suppression intervals (IS1 = 40 a 55 DAS; IS2 = 55 to 70 DAS; IS3 = 70 to 85 DAS and IS4 = without suppression intervals), with four repetitions. The following variables were evaluated: number, mass, pod length and diameter and yield. Treatment without water suppression interval associated with less saline water provides a greater number and diameter of pods. Higher salinity water affects pod mass and length. The use of water of greater or lesser salinity without interval of suppression of irrigation offers the highest yield of the peanut culture. Keywords: Arachis hypogaea L., water déficit, saline stress.

The use of plant growth-promoting bacteria can be one option for mitigating the impact of abiotic constraints on different cropping systems in the tropical semi-arid region. The aim of this study was to evaluate growth, leaf gas exchange and yield in maize inoculated with Bacillus aryabhattai, and subjected to water and salt stress. The experiment followed a randomised block design, in a split plot arrangement, with six repetitions. The plots comprised two levels of electrical conductivity for the irrigation water (ECw): 0.3 dS m-1 and 3.0 dS m-1; the subplots consisted of three irrigation depths (ID1: 50%, ID2: 75%, and ID3: 100% of the crop evapotranspiration (ETc)); while the sub-subplots included the presence or absence of Bacillus aryabhattai inoculant. A water deficit of 50% of the ETc resulted in the principal negative effects on growth, reducing the leaf area and stem diameter. The use of Bacillus aryabhattai mitigated salt stress and promoted better leaf gas exchange by increasing the CO2 assimilation rate, stomatal conductance, and internal CO2 concentration. However, irrigation with brackish water (3.0 dS m-1) reduced the instantaneous water use efficiency of the maize. Inoculation partially reduced the effects of abiotic stress due to morpho-physiological traits, and increased yield potential under water deficit with no salt stress.