Tropentag, September 16 - 18, 2026, Göttingen "Towards multi-functional agro-ecosystems promoting climate-resilient futures"

Optimising nitrogen use efficiency and soil fertility in semi-arid Sudan through legume residue-based management

¹Faculty of agricultural and fish scences-Al neelain universty, Crop Production, Sudan
²Faculty of Agriculture, University of Khartoum (U of K), Shambat, Sudan, Department of Soil and Environment Sciences

Abstract

Low nitrogen use efficiency (NUE) and progressive soil degradation are persistent constraints to crop productivity in semi-arid Sudan, where smallholder systems depend on low-input management under increasing climate variability. This study investigates the potential of legume-based crop residue management to enhance nitrogen dynamics, soil fertility, and system productivity within a guar (Cyamopsis tetragonoloba)–wheat (Triticum aestivum) rotation.
A combination of field experimentation and isotopic tracing (¹⁵N) was employed to quantify nitrogen recovery, residue mineralisation, and soil–plant nitrogen fluxes under contrasting residue management practices (incorporation vs. removal). Key soil indicators (soil organic carbon, total N, and moisture retention) and crop performance metrics were systematically evaluated.
Residue incorporation resulted in marked improvements in soil quality and nutrient cycling, with consistent increases in soil organic matter and plant-available nitrogen. Nitrogen recovery efficiency improved substantially under legume residue incorporation compared to conventional practices, accompanied by measurable gains in grain yield and biomass production. Enhanced soil moisture retention and improved soil structure further contributed to system resilience under water-limited conditions typical of Sudan’s semi-arid environments.
The findings demonstrate that integrating leguminous residues into cropping systems can reduce dependence on mineral fertilisers while sustaining or increasing productivity.
This approach represents a viable climate-smart strategy that strengthens nutrient use efficiency, enhances soil health, and supports multifunctional agro-ecosystems.
Aligned with the Tropentag 2026 theme, this research provides evidence-based insights for scaling sustainable land management practices in the Global South, particularly in dryland regions facing coupled soil fertility decline and climate stress.
“The study underscores the urgent need to mainstream residue-based nutrient management as a scalable and cost-effective pathway toward resilient and sustainable agricultural intensification in semi-arid systems.”

Keywords: Nitrogen use efficiency (NUE)، Crop residue incorporation، Semi-arid Sudan، Guar–wheat rotation، Soil fertility،¹⁵N isotope technique، Climate-smart agriculture

Contact Address: Nazar Omer Hassan Salih, Faculty of agricultural and fish scences-Al neelain universty, Crop Production, 11121 North khartoum, Sudan, e-mail: agrineelaingmail.com