Technical and economic viability of cowpea co-inoculated with Azospirillum brasilense and Bradyrhizobium spp. and nitrogen doses

Abstract

Biological nitrogen fixation efficiency can be increased by co-inoculation with Bradyrhizobium spp. and Azospirillum brasilense, allowing even greater uptake of water and nutrients, leading to higher yields and enabling the insertion of unusual crops, such as cowpea (Vigna unguiculata L. Walp.), in the agricultural production system in the Cerrado region of Brazil. Thus, this study aimed to evaluate the technical and economic viability of cowpea in the Cerrado region, as a function of N doses and co-inoculation of seeds with Azospirillum brasilense and Bradyrhizobium. The study was carried out in a no-tillage system in Selvíria, MS, Brazil. The experimental design was a randomized block design, with four repetitions, arranged in a 3 x 5 factorial scheme, corresponding to three types of inoculation (without inoculation - control, with two strains of Bradyrhizobium spp. SEMIA 6462 and SEMIA 6463 - the conventional inoculation of cowpea, and these two strains of Bradyrhizobium spp. plus A. brasilense strains Ab-V5 and Ab-V6); and five N doses (0, 20, 40, 80 and 160 kg ha-1), as urea, applied as topdressing. The following evaluations were performed: grain yield, total operating cost, effective operating cost, gross revenue, operating profit, profitability index, equilibrium price and equilibrium yield. Co-inoculation with A. brasilense increases cowpea grain yield, which makes cowpea production in the Cerrado region of Brazil technically and economically viable, without the need to apply N fertilizers in topdressing.

Co-inoculation with Bradyrhizobium spp. and Azospirillum brasilense in cowpea under salt stress

“…In addition to the ability to fix atmospheric N, bacteria of the genus Azospirillum are characterized as plant growthpromoting bacteria (PGPB), enabling beneficial effects for growth through the synthesis of phytohormones, possibly by increasing the capacity of plants to explore the soil more efficiently (Fukami et al, 2018). Studies with common bean (Phaseolus vulgaris L.) and cowpea (Vigna unguiculata L. Walp) indicate that inoculation with Azospirillum brasilense stimulates root exudation of flavonoids, inducing root hair growth and resulting in a significant increase in nodulation and, when subjected to co-inoculation with rhizobia, they increase their production potential, growth and BNF (Dardanelli et al, 2008;Galindo et al, 2020).…”

Dose ótima econômica de nitrogênio e folha diagnóstica para avaliação do estado nutricional do feijão-caupi

“…Calculation of the most economical dose according to Equation 1 indicated that the most economical N dose was equal to 26.0 kg ha -1 for basal + top-dressing application of the N fertilizer and to 35.6 kg ha -1 for fully top-dressing application (Table 3). Some studies may point out to lower doses as top-dressing or different management strategies to obtain better yield results; however, such techniques are employed during different phenological stages of the plant and/or with the use of inoculants, which may interfere in the final revenue (GALINDO et al 2020, OMURA et al 2020. It is also worth pointing out that the yields obtained with the most economical doses, for both fully topdressing and basal + top-dressing applications, were close to the maximum yield possible (technical) (Table 3), being equal to 81% and 76%, respectively.…”

Associative bacterial diversity of pangolão, a stressresilient tropical grass

“…Proteobacteria domination found in pangolão grass has been previously described for widely divergent species, such as wheat (Robinson et al 2016) and bamboo (Singh et al 2021), which indicates a possible general pattern among endophytes. The genera found included several species described as plant growth promoters, such as Stenotrophomonas (Ramos et al 2011), Pseudomonas (Josephine CM and Thomas 2021), Enterobacter, Pantoea (Lu et al 2021), Burkholderia, Herbaspirillum (Van Deynze et al 2018, Rhizobium (Hahn et al 2016, Silva et al 2020, Bacillus, and Paenibacillus (Govindasamy et al 2010, Kavamura et al 2013. A commercial product based on Bacillus strains has previously been licensed for use in maize to reduce drought effects, which was originally isolated from the native Brazilian cactus, Cereus jamacaru (Kavamura et al 2013).…”

“…Similarly, Bacillus isolated from Cereus jamacaru, a Brazilian native cactus, has been shown to induce drought resistance in several crops (Kavamura et al 2013). Brazilian Azospirillum inoculants, which are entirely based on strains isolated from maize, are currently recommended for maize, wheat, rice, and Brachiaria, and used as co-inoculants for soybean, cowpea, and the common bean (Brasil 2011, Galindo et al 2020.…”