Effect of Bradyrhizobium japonicum Strains and Inorganic Nitrogen Fertilizer on the Growth and Yield of Bambara Groundnut (Vigna subterranea (L.) Verdc) Accessions

Abstract

This study was set up to compare the inoculation of Bradyrhizobium japonicum strains and the application of nitrogen (N) fertilizers (urea with 46% nitrogen) on the growth and yield of Bambara groundnut accessions. The study results suggest that the benefits of Bradyrhizobium japonicum (B. japonicum) strain inoculation are greater and that the strain could reduce reliance and the excess amount spent by farmers to procure inorganic fertilizers and avoid the negative effect of N fertilizer on the environment after its use. Field studies were conducted in two different geographical locations, in Ibadan (Ib) and Ikenne (Ik), Nigeria, during the rainy season between August and December in 2019 and 2020. The experiment was arranged in a randomized complete block design (RCBD) in both locations and seasons and was replicated three times, with each block representing each replicate. It had a 10 × 6 factorial arrangement with one block holding the 10 accessions of Bambara groundnut inoculated with four B. japonicum strains. The second block had N fertilizer application and the third control block was without inoculation or fertilizer application. The 10 accessions of Bambara groundnut used in the study were as follows: TVSu-378, TVSu-506, TVSu-787, TVSu-1606, TVSu-1698, TVSu-1739, TVSu-710, TVSu-365, TVSu-475, and TVSu-305. Six seeds of each accession were coated with each of the four B. japonicum strains, namely, FA3, USDA110, IRJ2180A, and RACA6, before planting them in the field in both locations during the rainy season. In the next block, urea as N fertilizer (46% nitrogen) was applied to the uninoculated seedlings of accessions of Bambara groundnut 2 weeks after planting (WAP). The third block was the control with zero inoculation and zero fertilizer application. Data collected were subjected to an analysis of variance and mean and were separated using Duncan's Multiple Range Test (DMRT) at a p > 0.05 level of probability. It was found that FA3 inoculation significantly enhanced the growth traits of the accessions than other strains and N fertilizer application. In both locations and seasons, at 7 weeks after planting (WAP) and 12 WAP, plant height (19.54 and 22.71 cm), number of branches (33.63 and 62.77), number of leaves (116.54 and 209.25), terminal leaf length (5.62 and 6.00 cm), and width (2.09 and 2.56 cm) were recorded. The yield and yield components recorded at harvest were as follows: pod length (13.27 cm), pod width (9.08 mm), seed length (9.39 mm), seed width (6.92 mm), weight of 100 seeds (56.85 g), and yield/ha (750.72 kg). The yield and yield components were also significantly influenced by the inoculation of FA3 and RACA6 than other inoculated strains and N fertilizer application in both locations and seasons.

Effects of water volume of drip irrigation on soil bacterial communities and its association with soil properties in jujube cultivation

“…Some studies related to potential disease and jujube tree health mentioned the bacterial genus of Mycobacterium, which was more abundant in the FFS stage, however, there was no direct evidence of the effects of Mycobacterium on jujube health (Kwon et al, 2019;Ran et al, 2022). There was one study that investigated the effect of Bradyrhizobium, another bacterial genus that enriched in the FFS stage, on jujube growth, and suggested it as a potential biofertilizer for jujube trees (Bitire et al, 2022). In addition, another study mentioned Bradyrhizobium could enhance the drought tolerance of the jujube tree (Zhang et al, 2020a).…”

Seed Coat Pigmentation Plays a Crucial Role in Partner Selection and N2 Fixation in Legume Root-Microbe Associations in African Soils

“…However, supplying 5 mM NO3 − to inoculated seedlings of Bambara groundnut, soybean, and Kersting's bean led to reduced plant growth, nodule formation, and nodule dry matter across all seed coat colors. Furthermore, seedlings of Bambara groundnut with diverse seed coat colors revealed varied nodulation and plant growth under different field conditions in African soils in Cameroon, Burkina Faso and Nigeria [53][54][55].…”

Potentials of underutilized legumes in food security

“…Underutilized legumes can improve food security due to their high nutrient status, ability to improve soil nutrient, potentials to alleviate climate change effects, resilience to adverse effects of climate change such as (erosion, disease emergence, etc. ), plant disease control potential, and weed control (13,19,22) (Figure 1).…”