Rainfed-based production of Megathyrsus maximus in sub-Saharan Africa: the case of the semi-arid environment of Sudan

Abstract

The performance of rainfed-based Megathyrsus maximus (syn. Urochloa maxima and Panicum maximum) was investigated in the semi-arid pastures of Sudan. Split-plot complete design experiments with three replications were applied for two consecutive seasons (2020–2021). The treatments were two in situ rainwater harvesting systems [i.e. ridges plus terraces (RD) and terraces (TR)], three seeding rates (i.e. 1.5, 2.5 and 3.5 kg ha⁻¹) and two urea fertilisation rates [0 kg ha⁻¹ (Z) and 95 kg ha⁻¹ (F)]. These treatments were compared to a control (a flat, unfertilised and zero-tillage plot). Hydrological, biological and chemical indicators were used in the assessment. The results showed that the adopted RWH improved semi-arid pastures, with the RD treatment providing the best results for sustaining biomass production, water use efficiency, nutritional quality and soil quality. The highest plant density (112 000 plants ha⁻¹) was associated with the RD3.5 treatment. The FSR1.5-RD treatment resulted in the greatest plant length (63.5 cm) and number of leaves per plant (34.59), whilst the FSR3.5-RD resulted in both the highest fresh biomass (25.9 t ha⁻¹) and dry biomass (6.3 t ha⁻¹). The chemical compositions of M. maximus (i.e. crude protein, organic matter and nitrogen contents) were also substantially improved by fertilisation. The water use efficiency of M. maximus was plant-, management- and climate-dependent.