Effect of inhibitors on Zygophyllum dumosum plant litter decomposition

The contribution of soil fauna to decomposition processes was studied by elimination of specific biotic elements using chemical inhibitors. Changes in overall activity of the microbial community were studied in Zygophyllum dumosum leaves treated with the inhibitors Nemacur (nematocide), Edigan (biocide), and water (control). At the end of a one-year study, the decomposition of leaves treated with Nemacur or Edigan indicated a loss of about ten percent mass compared to leaves treated with water. The kinetic constant for mass loss exhibited a bi-phasic decomposition process (typical for the Negev Desert) for inhibitor- and water-treated leaves. However, the water-treated leaves exhibited a turnover by 30% higher than the other treatments on a yearly basis. The Shannon-Weaver (H') index of the microbial community in the decomposing leaves was found to be higher in the water-treated leaves only in the first sampling period, after which no differences between inhibitor- and water-treated leaves were observed. This study elucidates the importance of the biotic element in soil to decomposition processes in an arid climate, with focus on microbial communities.