Effects of different mulching formulations based on woody leaf biomass on soil fertility in semi-arid Burkina Faso

In Sahelian countries, declining crop yields and soil degradation necessitate the development of sustainable alternatives that enhance productivity while mitigating negative environmental impacts. Mulching, which relies on locally available woody species as organic inputs, is one of the most accessible technologies for rural populations. This study, conducted in a semi-arid Sahelian region of Burkina Faso, evaluated the effects of mulching formulations on soil fertility. Treatments used leaf biomass from five woody species (Azadirachta indica, Guiera senegalensis, Piliostigma reticulatum, Khaya senegalensis, and Vitellaria paradoxa), with or without urea and ash. The experiment design was a randomized complete block with 15 treatments and three replications. Mulching materials were applied annually at a rate of 2.5 Mg ha-1, and soil samples were collected from 0–20 cm, 0–5 cm, and 5–10 cm horizons. Laboratory analyses assessed aggregate stability, infiltration potential, bulk density, pHwater, organic carbon, total nitrogen, phosphorus, potassium, available K, and cation exchange capacity. Results showed that mulching improved soil physical parameters. Vitellaria paradoxa leaves combined with urea significantly enhanced aggregate stability. Infiltration potential increased with mixtures of Guiera senegalensis, Piliostigma reticulatum, and Azadirachta indica. Bulk density was reduced in the 0–5 and 5–10 cm horizons by Khaya senegalensis leaves. Vitellaria paradoxa and Azadirachta indica leaves combined with urea increased total soil carbon by 135–138% compared with the control. Total phosphorus, potassium, nitrogen, and cation exchange capacity were also significantly improved by formulations involving Vitellaria paradoxa, Piliostigma reticulatum combined urea, and Guiera senegalensis combined urea. These findings demonstrate that mulching with woody leaf biomass, supplemented by urea, provides a practical and sustainable strategy for improving soil fertility in Sahelian agroecosystems.