Response of Selected Soil Microbial Populations and Activities to Land Conversion
2013
Cochran, R. L. | Collins, H. P. | Alva, A. K.
A native shrub–steppe ecosystem converted to a series of irrigated agricultural fields was evaluated for biological indicators that may signal changes in soil processes during the initial stages of conversion and disturbance. Nine sites including undisturbed native shrub–steppe and center-pivot-irrigated fields with 1, 2, and 3 years of cultivation following conversion were evaluated. Cultivated fields had greater populations of culturable aerobic and pseudomonad bacteria, greater populations of nitrifying bacteria, increased nitrification potential, greater values of microbial biomass nitrogen (MBN), and different rates of substrate-induced respiration compared to native sites. Disturbance and soil mixing from field development, tillage, irrigation, compost amendments, and residue incorporation contributed to shifts in soil microbial populations and activities following conversion. Differences observed in microbial characteristics were influenced more by conversion of the native ecosystem to an irrigated agroecosystem and the addition of compost than by the length of time of cultivation.
显示更多 [+] 显示较少 [-]