Evaluation of biofertilizers and organic manures on yield and protein content of chickpea

Abstract:

Growers often treat Rhizobium inoculation as an afterthought rather than a central input decision for chickpea, despite the crop's well-documented dependence on effective nodulation for both yield and grain quality. Field research over two consecutive seasons at Enugu compared five nutrient management combinations, an untreated control, Rhizobium inoculation alone, phosphate-solubilizing bacteria (PSB) alone, farmyard manure alone, and a combined package of Rhizobium, PSB, and vermicompost, on nodulation, seed yield, and seed protein content of chickpea. The combined Rhizobium-PSB-vermicompost treatment produced the highest seed yield at 1642 kg per hectare, a gain of 58% over the control, alongside the highest seed protein content at 22.9%, roughly 5.1 percentage points above the control. Nodule number and nodule dry weight followed a broadly similar ranking, though PSB alone underperformed relative to Rhizobium alone on nodulation-related parameters despite showing a comparable yield response, pointing to phosphorus availability acting through a pathway separate from nodulation itself. Correlation analysis linked nodule dry weight most strongly to seed protein content among the parameters tested, ahead of seed yield, which supports treating nodulation quality as a leading indicator of nutritional outcome rather than only a yield predictor. These findings support combined microbial-organic nutrient management as a practical strategy for raising both the tonnage and the nutritional value of chickpea grown on nutrient-limited soils typical of this region.