MORPHOMETRIC CHARACTERIZATION AND AGRICULTURAL IMPLICATIONS OF GULLY EROSION IN GASHALA AREA, HONG LGA, ADAMAWA STATE, NIGERIA.

An impact assessment of gully erosion hazards on food security was carried out in ten (10) locations of arable lands in the Gashala environs in the year 2023. The study comprised measurements of the physical characteristics, which include texture, bulk density, porosity, length, depth and the width of each gully site. The gully volumes were also measured and classified according to Shahrivar and Christopher. (2012). The result of the physical properties indicated higher sand content relative to silt and clay. The particle size analysis revealed that the average values for sand, silt and clay were 52%, 27% and 20%, respectively, giving a textural class that is predominantly sandy loam. Due to larger macro-pores and fewer micro-pore spaces in sand, the bulk density tends to be high (1.74 g/cm³). This bulk density value of the soil surface was high enough to generate surface runoff that favoured soil erosion. The results of gully measurements revealed that Milendi was highest in volume (1,020 m³); Pavu has the longest gully (152 m), Contarabi 3 was deeper in size (5.2 m) and highest area covered by gully erosion (19.2 m2), Contarabi 2 has the lowest gully volume of 128 m³, the shallowest depth (1 m) and the least covered area (3.2 m²). The shortest gully was Contarabi 1 (19 m); the gully was widest at Naiwa (6.2 m). This variation in sizes of length, depth, width, area and volume indicated the impact of several factors of erosion active at the erosion sites. The rate of soil loss ranged from 100.8 t/ha/yr to 561.84 t/ha/yr across the locations, with the highest rate recorded at Pavu. The effects of this soil loss on food security were dual: on-site productivity (loss of crop yield, topsoil, nutrients and decline in soil quality) and off-site effects (seedling burial, chemical effects, burial of topsoil and alteration in soil-water regime and water table). Several factors for gully erosion, including climatic, anthropogenic, topographic, edaphic, and vegetative, are evident. Possible biological and engineering measures are also reported which might be beneficial. Biological measures of erosion control are basically adopted when the land slopes are smaller than 2% in general, and erosion problems are not severe. But when the land slopes are more than 2%, engineering measures may be necessary.