Assessment of the effects of pesticides on soil microarthropods in a farm land in university of Port Harcourt, Nigeria

Abstract

A study on the assessment of the effect of pesticide on soil microarthropod was carried out in a farmland at the University of Port Harcourt, Nigeria for three months. Two sites were employed - pesticide treated site and control site. Soil samples were collected from each site at the depths of 0 – 10.0cm and 10.0 – 20.0cm with the aid of soil augar. Microarthropods were extracted using the modified Berlese-Tullgren funnel extractor. A total of 101 soil microarthropods classified as Collembola, Oribatida, Gamisida were collected at both depths which were further identified to species level. At depth 10 – 20cm the Gamasida and Collembola groups were completely absent at all concentration (ie 0.15, 0.3, 0.375, 0.6) except at 1.45 limit. Control site at depth 0 - 10cm recorded Oribatida, Gamisida, and Collembola as 14(40.0%), 4(14.3%) and 2(33.3%). Soil pH, soil temperature, and soil moisture content had an average of 4.60, 26.3⁰c, and 15.72m³ respectively at the treated site and 270c, 5.01 and 18.2 at the control site. The statistical analysis showed that there was a significant difference between the numbers of microarthropods collected at the different depths in treated sites. Significant difference also exists within the different concentrations (P≤0.05). Soil pH, depth and pesticide concentrations are important factors in the density of micro-arthropods present in the soil. To avoid distortion and destruction of the ecosystem, agriculturist must have a clear understanding of the pesticide they wish to apply.

Key words: Collembola, Pesticide, Microarthropods, Oribatid