ABSTRACT
Peanut (Arachis hypogaea) is an important agricultural crop in Brazil, considered one of the most important oilseed crops cultivated. The use of fertilizer-solubilizing bacteria can mitigate salt stress. The objective of this study was to evaluate the gas exchange, growth, and water use efficiency of the peanut crop irrigated with brackish water under phosphate fertilization and inoculated with bacteria of the genus Bacillus sp. The experimental design used in this study was completely randomized, in a 4 × 2 × 2 factorial scheme, with 5 replicates, referring to the forms of fertilization (F1 - 0% phosphorus, F2 - 50% phosphorus, F3 - 100% phosphorus, and F4 - bovine biofertilizer), presence and absence of the inoculant and two levels of electrical conductivity of the irrigation water (ECw - 0.3 and 4.0 dS m-1). Fertilization with organic fertilizer (100% biofertilizer) and mineral fertilizer (50 and 100% phosphorus) associated with Bacillus sp. mitigated the damage caused by salt stress and promoted greater water use efficiency, chlorophyll index, internal CO2 concentration and stem diameter. The control treatment (without phosphate fertilization and without salt stress) and the application of Bacillus sp. promoted greater performance in net photosynthesis, transpiration rate, stomatal conductance, and plant height in peanut plants.
Key words:
Arachis hypogaea L.; plant nutrition; microorganisms
HIGHLIGHTS:
Inoculation with Bacillus sp. in peanut is effective in mitigating salt stress.
Organic fertilization with bovine biofertilizer is effective in the growth and gas exchange of pea-nut grown under salt stress.
Bacillus sp. mitigates salt stress by increasing water use efficiency in the peanut crop.
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Same uppercase letters comparing the average values of ECw in each form of fertilization and same lowercase letters comparing the average values of the different forms of fertilization at the same level of ECw do not differ statistically from each other by Tukey’s test (p ≤ 0.05); vertical bars represent standard error (n=4)
Same lowercase letters comparing the forms of fertilization with and without inoculation within the same ECw and same uppercase letters for the different ECw within each form of fertilization do not differ statistically from each other by Tukey’s test (p ≤ 0.05); vertical bars represent standard error (n=4)
Same uppercase letters comparing the average values of ECw in each form of fertilization and same lowercase letters comparing the average values of the different forms of fertilization at the same level of ECw do not differ statistically from each other by Tukey’s test (p ≤ 0.05); vertical bars represent standard error (n=4)
Same lowercase letters comparing the forms of fertilization with and without inoculation within the same ECw and same uppercase letters for the different ECw within each form of fertilization do not differ statistically by Tukey’s test (p ≤ 0.05); vertical bars represent standard error (n=4)
Same uppercase letters comparing the average values of ECw in each form of fertilization and same lowercase letters comparing the average values of the different forms of fertilization at the same level of ECw do not differ statistically from each other by Tukey’s test (p ≤ 0.05); vertical bars represent standard error (n=4)
Same lowercase letters compare the average values between forms of fertilization using the Tukey test (p<0.05); vertical bars represent standard error (n=4)