Soil Management and Efficiency of Rhizobia Strains of Cowpea Vigna unguiculata (L.) Walp. in the Tropics

Abstract

In the humid tropics, the largest obstacle to the implementation of sustainable farming systems is the reduced efficiency of nutrient use by crops. This study assesses the effectiveness of five selected rhizobia strains in symbiosis with cowpea (Vigna unguiculata (L.) Walp.), with the objective of replacing N fertilization in the predominant agricultural system used by smallholder farmers. The study was carried out in three adjacent areas with distinct agricultural uses: conventional tillage, itinerant agriculture, and a no-till system. The experimental design was in randomized complete blocks with four replicates and seven treatments: five rhizobia strains (BR3262, BR3267, BR3299, INPA3-11B, and UFLA 3-84) and two controls without inoculation (one without mineral N and another fertilized with 74 kg N ha -1 ). We measured the dry mass of 100 grains, nodules and shoots, as well as cowpea yields and calculated relative and absolute efficiency indices for dry biomass production of cowpea shoots. Agricultural uses affected the number and dry mass of the nodules and, consequently, the mass of the dry plant matter and bean yield. In terms of yield, there was a major difference between the conventional and the itinerant systems. Yield was around four times as high in the itinerant system (1009.9 kg ha -1 compared to 243.7 kg ha -1 ). Under conditions of cohesion-prone soils, the system of conventional tillage reduces the possibility of cultivation of a second harvest in the year even with inoculation or N fertilization.

Unlocking the Potential of Inoculation with Bradyrhizobium for Enhanced Growth and Symbiotic Responses in Soybean Varieties under Controlled Conditions

“…Absolute Symbiotic effectiveness percentage (ASE%) was estimated by contrasting the inoculated plant to the negative control, which was not inoculated or fertilized, using the technique described by Dos et al [27].…”

Long‐term agricultural management does not alter the evolution of a soybean–rhizobium mutualism

“…Agricultural management practices can affect rhizobium nodulation (Donizetti dos Santos et al. ), population size (Coventry and Hirth , Andrade et al. ), and diversity (Kaschuk et al.…”

“…Agricultural management practices can affect rhizobium nodulation (Donizetti dos Santos et al 2011), population size Hirth 1992, Andrade et al 2002), and diversity (Kaschuk et al 2006, Bizarro et al 2011. For example, larger and more diverse populations of rhizobia are sometimes found in no-till and organic soils than in those that are conventionally farmed (Ferreira et al 2000, Grossman et al 2011, Wang et al 2012.…”