Effect of Compost and Nitrogen Fertilizer on Sugarcane (Saccharum officinarum L.) Productivity at Kenana Sugar Scheme, Sudan

Sugarcane (Saccharum officinarum L.)is a globally vital crop, primarily cultivated for sugar production and increasingly as a renewable source for bioethanol (Nair & Sachan 2022). Originating from New Guinea, sugarcane is now widely grown across tropical and subtropical regions between latitudes 35° North and South and at varying elevations from sea level to high altitudes (Moore et al. 2013). Adapted to warm, humid climates and various soil types, including sandy loams and heavy clays, sugarcane is a highly productive C4 plant with an efficient photosynthetic mechanism that supports rapid biomass accumulation (Mwasinga 2018); (Tew & Cobill 2008). The economic importance of sugarcane lies mainly in its accumulation of sucrose in the stalk internodes, which constitutes the raw material for sugar production. The chemical composition of sugarcane stalks varies according to variety, age, climate, soil conditions, and agronomic practices, directly affecting sugar extraction efficiency (James 2008). However, this high productivity often leads to significant soil nutrient depletion.

Sugarcane is generally cultivated under intensive monoculture systems with cycles of planting and ratooning, practices that demand consistent inorganic fertilizer applications to sustain soil fertility and achieve high yields (Kusumawati & Noviyanto 2025). Rising fertilizer costs and environmental concerns have drawn attention to the importance of recycling organic matter within agricultural systems to improve soil health and support sustainable crop production (Unagwu 2019). Incorporation of organic matter such as compost enhances soil physical and chemical properties, improving nutrient uptake and plant growth. Global sugarcane cultivation generates substantial amounts of organic waste. Harvesting produces between 20 and 25 tons per hectare of trash mainly leaves and tops not sent for processing (Toharisman 1991). Additionally, sugar processing yields by-products like bagasse, filter mud, and molasses (Singh et al. 2021). For each ton of sugarcane processed, approximately 250 kg of bagasse and 36 kg of filter mud are generated, with filter mud comprising 1–7% of cane weight (Mena et al. 1985) ; (Salman et al. 2023). Traditionally, bagasse is used as fuel or raw material for other industries, while filter mud serves as a nutrient-rich organic amendment. Recycling these residues as compost improves soil fertility and physical characteristics and promotes sustainable farming (Iqbal 2018); (Stephen et al. 2024).

Application of compost derived from sugarcane residues enhances key soil chemical properties such as organic carbon, total nitrogen, available phosphorus, and potassium by stimulating microbial activity and nutrient cycling (Teshome et al. 2014). When integrated with inorganic nitrogen fertilizer, compost can further improve agronomic traits including cane height, stalk weight, and yield, as well as sugar quality parameters like Brix and sucrose content (Bekheet et al. 2018). Organic amendments also increase soil water holding capacity by 15–25% and microbial biomass carbon by 30–50%, contributing to annual increases in soil organic matter (Diacono & Montemurro 2011);(M. Sá et al. 2001). Although rich inorganic matter (90–95%), compost generally has lower nutrient concentrations than commercial fertilizers and functions primarily as a soil conditioner (Khater 2015). Composting of residues such as filter mud, vinasse sludge, and animal wastes using methods like windrow composting produces stable, mature compost with optimal nutrient profiles (Meyer 2013);(Misra et al. 2003); (Nemet et al. 2021). The ideal compost quality is indicated by a carbon-to-nitrogen ratio between 10 and 25 (Sullivan & Miller 2001);(Gao et al. 2010); (Guo et al. 2012) ; (Mahapatra et al. 2022).

Sugarcane’shigh nitrogen demand (200–300 kg N/ha) has led to extensive chemical fertilizer use, yet nitrogen use efficiency remains low (30–50%), causing environmental issues such as groundwater nitrate contamination and greenhouse gas emissions (Otto et al. 2016);(Thorburn et al. 2017);(Chen et al. 2022) ;(Van Beneden et al. 2010). Nitrogen is vital for tillering, early crop population, and photosynthetic efficiency since leaf nitrogen content influences photosynthesis rates (Otto et al. 2014);(Bassi et al. 2018). Studies show that integrating nitrogen fertilizer with compost improves yield components such as stalk girth, weight, and sugar yield; for instance, 46 kg N/ha combined with 15 t/ha compost produced superior cane and sugar yields on clay soils compared to sole applications (Zeng et al. 2020);(Sopandie et al. 2011).

Long-term sugarcane monoculture leads to soil degradation characterized by 30–40% loss of original soil organic carbon over 20 years, adversely affecting yield potential (up to 35% productivity reduction) and processing quality (2–4% sucrose loss) (Bottinelli et al. 2020);(Obour et al. 2017);(Verma et al. 2024). The industry faces ongoing challenges including biotic and abiotic stresses, high production costs, post-harvest losses, and low sugar recovery (Bhatt 2020). These factors underscore the need for sustainable cultivation practices and balanced nutrient management combining organic and inorganic inputs to maintain productivity and environmental sustainability (Chattopadhyay 2012).

In Sudan, sugarcane yields average around 60 t/ha, lower than many irrigated regions globally (Ibrahim 2020). Given the strategic importance of sugar production for domestic consumption and export, sustainable practices are essential. The Kenana Sugar Scheme, located on Vertisol soils of the White Nile, features heavy clay soils with high smectite content, significant shrink-swell behaviour, moderate fertility with low nitrogen and organic matter, and cation exchange capacity and electrical conductivity below 2 mS/cm³ (Emam & Musa 2011); (Ganawa & Kheiralla 2011).

Mechanization and exclusive reliance on chemical fertilizers have contributed to soil compaction and degradation (Pankhurst et al. 2003); (Batey 2009) ; (Iqbal 2018). There is limited research on integrated use of compost and nitrogen fertilizer in this context, making investigation necessary to optimize both yield and soil health.

Accordingly, a research project was initiated in 2023/2024 to investigate the effects of compost application on sugarcane production under the conditions of the Kenana Sugarcane Estate. For the above mention reasons the main objective of this research is: Main objectives: • To evaluate the effects of compost and nitrogen fertilizer applications on the productivity of sugarcane at the Kenana Sugar Scheme.

Specific objectives: • To determine the optimum application rates of compost and nitrogen fertilizer to achieve the highest yield of sugarcane.