Enhancing Common Bean Tolerance to Short-term Droughts at the Reproductive Stage using a Soil Fertility Management Approach

Aims: This study was conducted to enhance the tolerance of common beans to drought events occurring at the reproductive stage, from a soil improvement perspective.

Study Design: Split plot completely randomized design was used.

Place and Duration of Study: Study was conducted in a screen-house at the Legumes and Oil Seeds Division of CSIR-Crops Research Institute, Ghana, from September 2021 to January 2022.

Methodology: Municipal Solid Waste Compost and inorganic fertilizer combinations were applied to common beans in a pot experiment. They included control, full rate compost (FRAC), full rate fertilizer (NPK 5:30:30 kg/ha) (FRG), FRG + half rate compost (HRAC) and FRG + FRAC. All soils were maintained at 80% field capacity (FC) from the start of the experiment. At flowering, two groups of plants were water stressed till 40 and 16% FC and returned to 80% FC till physiological maturity, while one group maintained 80% FC throughout study. Forty-five soil samples each and plant data were collected at 3, 7 and 10 weeks after planting. Samples were analyzed for soil organic matter (SOM) and water retention, soil nutrients, crop growth, yield and nutrient uptake. Water and nitrogen use efficiencies (W/NUE) were calculated after harvest.

Results: During the growing period, highest soil moisture (6-9 cm3/cm3) was retained by FRG and FRG+HRAC, FRG+FRAC; 20-38% more than FRAC and control but was not influenced by SOM. While FRG influenced the highest yield and WUE, combining it with compost rates reduced yield by 56-84% and WUE by 55-64%. WUE correlated positively with NUE.

Conclusion: Antagonistic effect observed with integrating compost with FRG is likely because compost was not properly cured and immobilized soil nitrogen. Farmers can mitigate short-term drought effects on common beans with adequate nutrient supply through fertilizer application; however, fertilizer should only be integrated with compost after compost quality analysis.