Impact of mulching treatments on growth, yields, and economics of common bean (Phaseolus vulgaris L.) in Eastern Tanzania

Abstract

Mulching is a widely used agricultural practice that can significantly affect crop growth, yield, and economic outcomes, particularly in regions with varying climatic conditions. The present study evaluated the influence of various mulching practices on the growth, yield, and economic viability of common bean (Phaseolus vulgaris L.) cultivation in Tanzania. The study was conducted across three sites in the eastern agro-ecological zone of Tanzania: Kipera (E4 200–1000 m.a.s.l.), Mgeta (E14 500–000 m.a.s.l.), and Ndole (E2 500–1200 m.a.s.l.). Four mulching treatments—polythene mulch, synthetic biodegradable mulch, rice husk mulch, and a control group—were applied to assess their effects on plant growth and yield components. Results revealed significant variations in growth parameters and yield components across sites. Notably, polythene mulch and synthetic biodegradable mulch consistently outperformed the other treatments. Polythene mulch resulted in an average plant height of 68.37 cm, followed closely by synthetic biodegradable mulch at 68.26 cm, both significantly (p < 0.05) taller than rice husk mulch (62.79 cm) and the control (57.74 cm). Canopy coverage was highest with polythene mulch at 61.7%, followed by synthetic biodegradable mulch at 60.5%. Grain yields did not differ significantly between synthetic biodegradable mulch (2.64 t ha−1) and polythene mulch (2.67 t ha−1). Economic analysis indicated that synthetic biodegradable mulch offers promising marginal returns (MR: Tshs. 3,787,450 or USD 1,469) and a benefit-cost ratio (BCR) of 1.91, compared to polythene mulch (MR: Tshs. 4,114,050 or USD 1,595, BCR: 2.06). These findings suggest that synthetic biodegradable mulch is a sustainable and economically viable option for enhancing common bean production across diverse agro-ecological settings in Tanzania.