Response of microbial community in the arid land to wheat residues and soil compaction


This study was conducted to evaluate the effect of soil compaction and wheat residues on microbial activity, bacterial abundance, fungal abundance, organic carbon and mineralisation constant following two months of pots incubation at the College of agriculture, AL-Qasim Green University in Iraq. Compaction level was induced by hummer drop to bulk density of 1.70 g/cm3. Results proved overall that microbial activity, total bacteria, total fungi and organic carbon increased significantly after addition of wheat straw only. Soil compaction overall reduced significantly microbial activity, total bacteria, total fungi and limited the mineralization process in soil as compared to the non-compacted soil. However, soil compaction did not significantly affect organic carbon in the compacted soil in a comparison to the non-compacted soil. The application of wheat straw to the compacted soil maximized the microbial activity, total bacteria, total fungi and mineralization constant compared to the compacted control treatment. The percentages of rehabilitation of compacted soil were 28%, 85 %, 66 %, 10% and 20 % for microbial activity, total bacteria, total fungi, organic carbon and mineralization constant respectively. This study demonstrates that soil compaction minimised soil microbial community and this status can influence soil nutrient cycle. Furthermore, the amendments of wheat residue to the compacted soil may enhance soil microbial community and decomposition process. More importantly, the response of bacterial community to plant residues in the compacted soil was higher than fungal community indicating that bacterial community is more resistant and resilient to the disturbance of logging in the arid land.