Faculty of Agriculture and Environmental Sciences (FAES)

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Browsing Faculty of Agriculture and Environmental Sciences (FAES) by Author "Twebaze, Jeniffer"

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    Effects of Agrochemicals on Soil Bio-Physico-Chemical Properties in Potato Production Systems in the Highlands of South Western Uganda.
    (Kabale University, 2024) Twebaze, Jeniffer
    The ardent use of agrochemicals is on the rise to increase the production and productivity of various crops in Uganda. The increased agrochemical usage could probably pose undesirable impacts on the soil environment that could outweigh the yield benefits. This study was conducted in Kabale District to investigate the effects of the frequent use of agrochemicals on soil macrofauna (earthworms, termites, millipedes, and beetles) diversity and abundance in a potato production system where chemicals are used almost throughout the year. The study also assessed the effects of the agrochemicals on the soil chemical properties (pH, Electrical Conductivity - EC, Soil Organic Matter - SOM, total nitrogen - N, Extractable phosphorus - P, Exchangeable potassium - K) as well as the concentration of heavy metals (lead - Pb and cadmium - Cd). Commonly used agrochemicals by farmers were determined by using a structured questionnaire administered to 150 potato farmers in Kabale District. A complete randomized block (CRB) design with three blocks, three treatments, and three replicates was used to assess the effects of frequently used agrochemicals on soil bio-physical-chemical properties. Soil samples were collected and analysed for the soil's physical and chemical properties and heavy metals Cd and Pb. Soil macrofauna samples were collected three times per season, and the observed organisms were counted and recorded to determine their abundance, evenness, and richness. It was observed that the majority of the macrofauna existed in the topsoil layer at a depth of 0-10 cm other than the 10-30 cm. Termites were significantly higher than other macro-organisms (p<0.05), but for the rest of the organisms (earthworms, beetles, and millipedes), there were no significant differences in individual populations (p>0.05). The findings of the study further revealed that the majority of potato farmers (>90%) rely on the use of agrochemicals. The soil samples collected showed that potato-grown fields were low in significant soil macronutrients N, P, and K and had low EC and Organic matter. Lead (Pb) was recorded in the range of 0.05-113 mg kg-1 and Cd between 0.05-32 mg kg-1 with most fields having higher concentrations beyond the recommended levels of <40 mg kg-1 and <1.0, mg kg-1 respectively. A strong significant positive correlation was observed between N and Organic Matter (r =0.992** p<0.01), but a strong significant negative correlation between Pb and the Millipedes population (r = -0.667* p<0.05) was recorded. The study recommends further monitoring of the presence of heavy metals in soils of potato-grown fields and a reduction in the use of agrochemicals to conserve soil health.