Abstract:

This research work determined the effect of herbicides on soil physicochemical properties, microbial activities and growth of maize plants in soils cultivated with maize in plastic pots. Percentage CO2 evolved, dehydrogenase activity and microbial biomass carbon were analysed in the soil samples. Calcium, Magnesium, potassium, Copper, Manganese, and Zinc in the samples were determined using the atomic absorption spectrophotometer. Electrical conductivity and exchangeable acidity were also determined. Plant height, the height of ear and leaf area of maize plants were determined as growth indices. The highest plant height of 72.67 cm was obtained in week 2. There were no significant differences in the pesticide-treated soil samples' organic carbon, organic matter, and total nitrogen composition. The highest total nitrogen and organic carbon values of 1.48±0.13% and 2.13±0.84% were obtained in UTLX3 and UTLX1 soil samples, respectively. The dehydrogenase activity, microbial biomass carbon and CO2 respired increased in lambda-cyhalothrin treated soils compared to the control. The highest dehydrogenase (43.40±0.10 µgg-1h-1), microbial biomass carbon (7.75±0.05 kgC m2) and microbial respiration (2022.50±0.50 mgkg-1) values were obtained in LAMX3, LAMX2, and LAMX3 treated soil samples. Treatment with pesticides caused significant changes in the mineral content of the soil samples. The microbial activities of soil samples were also reduced except for lambda-cyhalothrin treated soils. Hence, herbicides should be applied in moderation to avoid the immobilization of minerals and depletion of soil microbial activities, which severely affects the mineralization and cycling of nutrients.

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