Valorization of Agro-industrial Bio-waste from Seed Cotton in the Restoration of Degraded Soils in the District of Korhogo in Northern Côte d'Ivoire

The objective of this study was to restore degraded soils with organic manure from agro-industrial bio-waste (seed cotton) in the Department of Korhogo in Northern Côte d'Ivoire.

The research plots were set up in a Fisher block experimental design with four treatments, namely T0 (control soil), T1 (bio-waste at 1 month of biodegradation), T2 (bio-waste at 3 months of degradation) and T3 (bio-waste at 6 months of degradation).

On each of the treatments, bio-waste was applied using spreading technique and the variety F8128 of corn was sown to evaluate the agronomic performance of bio-waste. Four agronomic parameters were measured: Plant height, collar diameter, ear weight and grain yield. Likewise, the physical, physico-chemical and chemical analyses of the soil were performed before sowing and after corn harvesting.

The work was carried out from 2018 to 2019 in the district of Korhogo in Northern Côte d'Ivoire.

Our study shows significant increase in corn grain yield in each of the treatments (T1 = 2.26 T/ha; T2 = 1.98 T/ha and T3 = 1.48 T/ha) compared to the control (T0 = 1 T/ha). Laboratory analyses of the soil and bio-waste indicate a very low level of organic matter (MO varies from 0.55 to 0.77 g.kg-1) in the soil of the experimental plot and good mineralization of the organic matter in the bio-waste regardless of the decomposition time (C/N varies from 12 to 13). After application of the bio-waste, the organic matter content (T3 = 10.28 g.kg-1; T1 = 23.61 g.kg-1 and T2 = 23.63 g.kg-1) and nitrogen content (T3 = 0.69 g.kg-1; T1 = 1.16 g.kg-1 and T2 = 1.21 g.kg-1) of the various treatments significantly increased compared to the control soil (MO = 0.66 g.kg-1 and N = 0.013 g.kg-1). The pH level increased where the organic manure was applied becoming slightly acidic (5.7 to 6.4) compared to the control that had strong acidic reaction (4.8 to 5.1).

Based on our study, it is evident that organic fertilizer has positive effect on corn yield. The seed cotton bio-waste has had an improving effect on the degraded soil of in Northern Côte d’Ivoire.