Tropentag, September 10 - 12, 2025, Bonn "Reconciling land system changes with planetary health"

Comparative effect of sunn hemp with farmyard manure and inorganic fertiliser levels on selected soil properties, growth, yield and quality of cotton in titanium-mined reconstituted soils in Kwale county, Kenya

Pwani University, Dept. of Crop Science, Kenya

Abstract

Cotton yields in Kenya have declined over the years, with Kwale County being one of the areas that were once suitable for cotton farming experiencing serious setbacks with soil loss and reduced arable land due to enhanced mining activities. The aim of this study was to assess the potential of combining sunn hemp with farm yard manure and inorganic fertilisers to enhance soil chemical properties, cotton growth, yield, and fiber quality in the titanium-mined reconstituted soils of Kwale County. Field trials were conducted in May–August 2022 and September–December 2023 at Base Titanium, Kwale County, on a randomised complete block design with three replications. Ten treatments with variation in mixtures of sunn hemp, farmyard manure (7.5 or 15.0 tons/ha), and NPK fertiliser (100 or 200 kg/ha), were applied in four site conditions: undisturbed soil, topsoil-covered mined land, reconstituted soil without topsoil, and reconstituted soil with topsoil. Data collected included: Soil chemical properties, cotton growth, yield and fiber quality. Data collected was subjected to analysis of variance (ANOVA) using the SAS statistical package (SAS, Version 10). Significant means at the F-test were ranked using Turkey's test at a 5% significance level. Results indicated that cotton with 200 kg NPK with sunn hemp significantly enhanced cotton chlorophyll content by (32.7%), leaf numbers (78.6%), plant height (41.5%), number of bolls (77.3%), lint weight (86.6%), fiber strength (19.48%), fiber length (8.11%), and moisture content (15.79%) compared to control. These findings indicate the possibility of utilising organic and inorganic input mixtures in reclaiming mined land and improving cotton productivity, though additional long-term studies are recommended for large-scale application and validation.
Keywords: Cotton, green manure, rehabilitation of mined land, integrated soil fertility management, fiber quality, climate-smart agriculture, restoration of soil.

Keywords: Cotton, climate-smart agriculture, fiber quality, green manure, integrated soil fertility management, rehabilitation of mined land, restoration of soil

Contact Address: Consolata Muindi, Pwani University, Dept. of Crop Science, Kilifi, Kenya, e-mail: consamuindi60gmail.com