Influence of Irrigation and Soil Amendments on Growth, Yield, and Quality of French Beans in Salt-affected Soils

French beans (Phaseolus vulgaris L.) are crops grown mainly due to their nutritional benefits. The irrigation methods and soil amendments aid in amelioration of salt-affected soils as well as improving the productivity of crops. The experimental site was located in Kabaa irrigation scheme in Machakos County. The study was carried out in two consecutive seasons during the short rains (October-December 2021) and the long rains (March-May 2022). This study evaluated the effects of irrigation and soil amendments on the growth, yield and quality of French beans. The experiment was set up in a Randomized Complete Block Design (RCBD) in a split plot arrangement with the main plots (basin and furrow irrigation) and the sub-plots (gypsum + farmyard, fertium non-salt, vermicompost, control, and farmyard manure) replicated thrice. The data collected was subjected to Analysis of Variance (ANOVA) using R-Software 2023, version 4.0.3. Where significant differences were observed, means were separated using the Least Significance Difference (LSD) at a 5% level of significance. The findings from this current research indicate that in terms of the soil amendments, gypsum and farmyard blend resulted in the maximum plant height (67.80cm), pod length (15.97) and pod dry weight (0.41g). Furrow irrigation resulted in the lowest mean values of the parameters in season one and season two. The findings reveal that gypsum + farmyard and basin irrigation contributed to significant improvements in growth, yield and quality of French beans. The study therefore recommends the adoption of gypsum + farmyard mixture and basin irrigation method in boosting French bean productivity by farmers. The policy makers can propose to farmers the soil amendments for sustainable saline soil management.

Basin irrigation was consistently superior to furrow irrigation in eliciting yield and quality attributes of French beans in both seasons.

Gypsum + farmyard manure under basin irrigation resulted in longest pod lengths out of all the treatments which may be attributed neutralization of salinity levels in water, improved electrical conductivity and exchangeable sodium percentage that provided conducive plant development conditions. Pod length is considered key quality attribute of French bean.

Decision or policy-makers need to focus on more integrative approaches as alternative tools and opportunities to increasing access to soil amendments to ameliorate the effects of soil salinity/sodicity for increased French bean yield and quality.