Understanding how interactions between management practices and soil biota within agroecosytems can help to develop practices that will maximize crop productivity while helping to reduce human input. A key indicator to how agricultural management practices are affecting soil microbial dynamics of soils is to evaluate microbial biomass.  The soil microbial biomass is an important regulator of nutrient transformation and storage of many vital nutrients and is also an important component of organic C mineralization.  Previous research has demonstrated that microbial biomass is a sensitive indicator of differences in sustainable cropping systems, including examining effects of tillage, crop rotations, and soil type on nutrient turnover and organic C and also considered to be a reliable indicator of soil quality. This research is focused on how microbial biomass carbon and microbial activity responds to different agricultural management practices in semi-arid soils.  The effects of different irrigation, nitrogen addition, and strip-tillage vs. conventional tillage practices used in peanut production systems were examined to determine whether they had any impact on microbial activity.  Soil samples were over a two year period from 2007 to 2008.  Microbial biomass carbon was determined using the chloroform fumigation extraction method. 

Results/Conclusions

The different tillage treatments had no effect on the microbial biomass carbon irrespective of the differences in growing season conditions between years.  When compared to late season drought, full irrigation resulted in the highest levels of microbial biomass.  In contrast, there was no statistical difference in the microbial biomass between early season drought and full irrigation.  Nitrogen inputs significantly decreased microbial biomass carbon irrespective of irrigation.  These results indicate that current management approaches for peanut production systems on the Southern High Plains may uncouple microbial activities from ecosystem process leading to the need to increases inputs of energy and nutrients.