Soil Organisms (Apr 2023)
Effect of three different land use types on the temporal dynamics of microarthropod abundance in the high Guinean savanna of Ngaoundéré (Adamawa, Cameroon)
Abstract
Soil degradation and desertification negatively affect agricultural productivity. It affects 46 % of Africa’s land area, where agriculture sustains over 50 % of the economy in many countries. Microarthropod communities’ abundance and composition are important components for soil health and quality assessment. Unfortunately, there is a dearth of information on microarthropods in central Africa in general and Cameroon in particular. We, thus, evaluated the population dynamics of Acari and Collembola as influenced by season, maize cultivation and fertilization in the high Guinean savanna agro-ecological zone (HGSAZ) of Cameroon. The abundances of Acari groups (Oribatida, Gamasina, Uropodina, Prostigmata, Astigmata) and Collembola were recorded. They were extracted from a field trial consisting of three plots of maize and one savanna plot that was established at Dang (Ngaoundéré 3, Adamawa region) in May of 2017 and 2018. The first plot received dead organic matter (DOM) while the second was treated with chemical fertilizer (NPK 20:10:10 at the rate of 8.75g/m2). The third plot received no external input and served as a control. The adjacent grassy savanna was the out-of-field control. Results revealed that microarthropods were more abundant in the rainy than dry season. Overall, abundances of 16 tsd. ind./m2 for Acari and 8 tsd. ind./m2 for Collembola were recorded in the savanna control. In the experimental field with maize cultivation, the highest abundances of Acari (20 tsd. ind./m2) and Collembola (7 tsd. ind./m2) were recorded in the plot that received dead organic matter (DOM), while the control plot without DOM (10 tsd. ind./m2 for Acari and 2 tsd. ind./m2 for Collembola) and the plot with chemical fertilizer (8 tsd. ind./m2 for Acari and 8 tsd. ind./m2 for Collembola) had the lowest abundances. Therefore, application of NPK and removal of DOM from cultivated areas have negative effects on soil microarthropods, and could result in very high costs for farmers to maintain soil fertility. In contrast, mulches are safe, simple and easily accessible to local farmers, promote soil biota and have a positive influence on soil structure and microclimate. Further, knowledge from the present study may contribute to the improvement of soil health and quality and boost agricultural productivity in the HGSAZ of Cameroon.
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