Vol. 8, Issue 11, Part I (2025)
Abstract
A field experiment on effect of pre and post emergent weedicides on soil micro-organisms and enzymatic activities in maize was carried out during Kharif, 2024 at Main Agricultural Research Station, University of Agricultural Science, Raichur. The experiment was laid out in Randomized Complete Block Design with three replications and thirteen treatments. Among the different herbicide treatments, pyroxasulfone 85% WG @ 255 g a.i. ha-1 as PE fb tembotrione 34.4% SC @ 48 g a.i. ha-1 as POE had recorded significantly minimum population of bacteria, fungi, actinomycetes and dehydrogenase, urease, alkaline phosphatase activity at both first (12.11×106, 13.67×104, 55.33×103 cfu g-1soil, respectively) and (3.32 µg TPF, 9.26 µg NH4-N g-1, 5.57 µg PNP, g-1 soil day-1, respectively) second week after herbicide spray (14.33×106, 13.33×104, 60.67×103 cfu g-1soil, respectively) and (3.32 µg TPF, 10.26 µg NH4-N g-1, 3.32 µg PNP, g-1 soil day-1, respectively) higher nutrient uptake by maize (131.15, 29.06 and 125.16 kg ha-1 of N, P and K, respectively), lower nutrient uptake by weeds (11.86, 3.58 and 7.98 kg ha-1 of N, P and K, respectively) and higher nutrient availability at harvest (235.11, 52.69 and 258.16 kg ha-1 of N, P2O5 and K2O, respectively) which was statistically comparable with application of pyroxasulfone 85% WG @ 170 g a.i. ha-1 as PE fb tembotrione 34.4% SC @ 48 g a.i. ha-1 as POE and pyroxasulfone 85% WG @ 127.5 g a.i. ha-1 as PE fb tembotrione 34.4% SC @ 48 g a.i. ha-1 as POE treatments. Weedy check recorded significantly higher microbial population at all the stages as compared to other herbicidal treatments, lower nutrient uptake by maize and higher nutrient uptake by weeds.
