Distribution of ?-Glucosidase Activity within Aggregates of a Soil Amended with Organic Fertilizers
Saeid Hojati and Farshid Nourbakhsh
DOI : 10.3844/ajabssp.2009.179.186
American Journal of Agricultural and Biological Sciences
Volume 4, Issue 3
Problem statement: Distribution pattern of enzyme activities in soil aggregate size classes as affected by organic amendments is not well understood. Approach: A study was conducted to evaluate the effects of repeated annual application of Cow Manure (CM), Sewage Sludge (SS) and Municipal Solid Waste Compost (MSW) on the distribution of ?-Glucosidase (?G) activity within aggregates of a soil. Soil samples were collected from 0-15 cm of a soil which, had been treated annually from 1999-2006 at 4 application rates with three replications. A control (with no application) was also run. Soil organic C content and ?G activity were measured in 5 aggregate size fractions. Results: Results illustrated that application of the amendments decreased the proportion of microaggregates (<0.25 mm). The proportion ranged from 64% in control to 35% in MSW. In contrast, the proportion of macroaggregates (>0.25 mm diameter) enhanced from 35% in control to 65% in MSW. Application of organic amendments modified the distribution of Soil Organic C (SOC) content and ?G activity. Distribution of SOC in macroaggregate classes was not identical in CM, SS and MSW treatments. The distribution pattern of ?G activities in aggregate size classes was dissimilar to those of SOC contents. In general, an increasing trend was observed in ?G activity as the aggregate sizes increased. The highest level of ?G activity was observed in aggregate size classes of >2 mm of all applied soils. Among the solid waste treatments, CM induced greater ?G activity in macroaggregates. For all aggregate size classes, the lowest level of ?G activity was observed in control. Conclusion/Recommendations: To conclude, organic fertilization increased the proportion of macroaggregates to microaggregates. The highest activities of ?G and SOC contents were observed in macroaggregates and in soils received the highest rates of organic fertilizer applications.
© 2009 Saeid Hojati and Farshid Nourbakhsh. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.