LAND USE EFFECT ON PLANT SPECIES DIVERSITY AND SOIL MICROBIAL BIOMASS CARBON IN ALETA CHUKO OF SIDAMA REGION, ETHIOPIA

<p><strong><span lang="EN-US">Background</span></strong><span lang="EN-US">. There was a widespread conversion of species-diverse traditional agroforestry to </span><span lang="EN-US">monoculture land uses in Aleta Chuko, Ethiopia, particularly since </span><span lang="EN-US">1990. However, the effect of such land use change on plant species </span><span lang="EN-US">diversity </span><span lang="EN-US">and soil microbial biomass in agroecosystems was not investigated. <strong>Objective.</strong> To investigate </span><span lang="EN-US">the effect of </span><span lang="EN-US">land use (LU) on plant species diversity and soil microbial biomass carbon (MBC), determine association between plant species diversity and MBC in Aleta Chuko district. <strong>Methodology</strong>. Three LU systems, namely</span><span lang="EN-US">,</span><span lang="EN-US"> Coffee-Enset Agroforestry (CEA), Eucalyptus Woodlot (EW), and </span><span lang="EN-US">Chat M</span><span lang="EN-US">ono-cropping (CM)</span><span lang="EN-US">,</span><span lang="EN-US"> were aligned in three transect lines based on </span><span lang="EN-US">a </span><span lang="EN-US">spatial analog design; four (4) plots </span><span lang="EN-US">were used </span><span lang="EN-US">for each LU from individual </span><span lang="EN-US">transects, for</span><span lang="EN-US"> a total of 36 plots (12 plot per LU), and then 108 soil samples were taken </span><span lang="EN-US">from</span><span lang="EN-US"> three diagonal pits within 20 × </span><span lang="EN-US">20 m,</span><span lang="EN-US"> which was also used for species diversity assessment. </span><span lang="EN-US">The soil</span><span lang="EN-US"> MBC was extracted </span><span lang="EN-US">via</span><span lang="EN-US"> chloroform fumigation extraction and analyzed at plot level. <strong>Results</strong>. </span><span lang="EN-US">A total of 37, 16, and 8 plant species were recorded in the CEA, EW, and CM treatments, respectively. The Shannon diversity indices were 2.40, 0.40, and 0.03 for CEA, EW, and CM, respectively. Jaccard’s index indicated negligible similarity (0.15) among the three LUs. However, consistent similarity was observed between transects within each LU, with higher similarity (0.75) recorded for CEA among transects. MBC was 586.3, 298.2 and 313.8 µg g<sup>-1</sup> soil in the CEA, CM and EW </span><span lang="EN-US">soils, </span><span lang="EN-US">respectively. MBC in CEA was significantly </span><span lang="EN-US">greater</span><span lang="EN-US"> than </span><span lang="EN-US">that in </span><span lang="EN-US">the </span><span lang="EN-US">other</span><span lang="EN-US"> two </span><span lang="EN-US">LUs</span><span lang="EN-US">, but there was no significant difference between CM and EW (<em>p < 0.05</em>). There was a strong positive correlation (<em>r = 0.854</em>) between MBC and plant richness. <strong>Implication</strong>. The strong positive association between MBC and plant diversity implies that decline in plant diversity result </span><span lang="EN-US">in associated degradation of MBC that impede</span><span lang="EN-US"> the sustainability of agroecosystems. <strong>Conclusion</strong>. The expansion of monoculture has weakened plant diversity and soil microbial biomass carbon in agroecosystems. Further study </span><span lang="EN-US">on the</span><span lang="EN-US"> plant species</span><span lang="EN-US">-</span><span lang="EN-US">specific association of microbial biomass</span><span lang="EN-US"> is needed</span><span lang="EN-US">. </span></p>