Different Tillage and Nutrient Management Methods on Soil Characteristics and Maize Productivity

Abstract

Declining soil fertility and unsustainable land management practices remain critical challenges to maize productivity and food security in Ghana’s peri-urban regions. Tillage and nutrient management are two key practices influencing soil quality and crop performance. Conventional tillage methods such as disc ploughing and harrowing improve short-term soil loosening and weed control but often lead to compaction, erosion, and loss of organic matter. In contrast, conservation tillage, particularly no-till, enhances soil structure, moisture retention, and microbial activity by minimizing disturbance. Similarly, while inorganic fertilizers such as NPK, provide rapid nutrient supply, their overuse is associated with soil acidification and reduced biological activity. Organic amendments including poultry manure, processed coconut waste, and processed food waste offer a sustainable alternative, improving soil organic matter, nutrient cycling, and long-term fertility. Although tillage and fertilizer use have been widely studied, their interactive effects on soil health and crop performance under urban-peri-urban farming systems remain underexplored. This study therefore evaluated the combined effects of tillage methods and nutrient management strategies on soil physical, chemical, and biological properties, as well as maize growth and yield, during the 2023 growing season at the University of Ghana Research Farm, Legon. The experimental site, situated in the Guinea Savanna Zone, is characterized by Ferric Acrisol soils (sandy-clay-loam texture), mean annual rainfall of 1150 mm, temperature of 30.5 °C, and relative humidity of 85%. A randomized complete block design (RCBD) with three replications was used, consisting of two tillage practices, disc ploughing at 30 cm followed by harrowing at 20 cm (DPH), and no-till (NT) combined with four nutrient management methods: processed coconut waste (PCW, 20 t/ha), Asase Gyefo premium organic fertilizer (AG, 20 t/ha), poultry waste (PW, 20 t/ha), and NPK (15:15:15, side-placed at 7 and 21 DAS). Plot sizes measured 21 m × 3.6 m, with a plant population of 210 per plot. Growth parameters assessed included plant height (cm), leaf length (cm), leaf breadth (cm), stem girth (cm), and number of leaves, while yield components measured were ear height (cm), ear weight (g), number of rows per cob, number of grains per row, 1000-grain weight (g), grain yield (t/ha), and above-ground and below-ground biomass weight (g). The results demonstrated significant improvements in soil properties under organic nutrient management, particularly PW and AG. Under DPH, bulk density decreased from an initial 1.50 g/cm³ to 1.14 g/cm³ under PCW and 1.18 g/cm³ with PW, corresponding to porosity increases from 43.59% to 56.82% and 55.60%, respectively. Soil pH improved markedly, rising from 4.85 to 7.37 under PW in NT plots, while organic carbon increased from 0.52% to 0.87% under AG in NT. Nutrient availability also improved, with PW increasing available calcium to 2.61 Cmol/kg and potassium to 0.78 Cmol/kg, while AG enhanced nitrogen availability to 0.087%. Biological activity was highest under PW and AG, with bacterial load increasing from 3.88 ×10⁴ to 6.03 ×10⁴ cfu/100 µl under PW in NT. Maize productivity responded positively to organic amendments, with PW producing the highest grain yield (6.1 t/ha) compared to NPK (4.2 t/ha). These findings highlight the potential of integrating conservation tillage particularly NT with organic nutrient sources, particularly poultry and Asase Gyefo premium organic fertilizer, as sustainable alternatives to inorganic fertilizers. Promoting such practices through extension support and policy incentives can enhance maize productivity, restore soil health, and improve the resilience of peri-urban farming systems in Ghana.