| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4383194 | Applied Soil Ecology | 2008 | 8 Pages |
Agroforestry and grass buffers have been shown to improve soil properties and overall environmental quality. The objective of this study was to examine management and landscape effects on water stable soil aggregates (WSA), soil carbon, soil nitrogen, enzyme activity, and microbial community DNA content. Treatments were row crop (RC), grass buffer (GB), agroforestry buffer (AG), and grass waterways (GWW). A corn (Zea mays L.)–soybean (Glycine max L.) rotation under no-till management was established in a watershed in northeast Missouri in 1991; grass buffers were implemented in 1997. Grass buffers, 4.5 m wide and 36.5 m apart, consisted of a mixture of redtop (Agrostis gigantea Roth), brome grass (Bromus spp.), and birdsfoot trefoil (Lotus corniculatus L.) on contour within the watershed. Agroforestry buffers have pin oak (Quercus palustris Muenchh.) trees distributed down the center of the grass buffers on one half of the watershed. Soils were collected from two transects extending from the summit to lower landscape positions within the grass and agroforestry portions of the watershed in June 2006. Soil enzymes studied include: fluorescein diacetate hydrolase, β-glucosidase, glucosaminidase, and dehydrogenase. Soil DNA content was determined as an alternative for microbial biomass. WSA was significantly different among treatments and landscape positions. WSA decreased from GWW > AG > GB > RC management treatments and also decreased from lower > middle > summit landscape positions. Soil carbon and nitrogen were highest for the GWW treatment and lowest for RC. The landscape position effect was significant for RC and AG treatments. Fluorescein diacetate, β-glucosidase and glucosaminidase enzyme activities were significantly higher in buffers and GWW areas than RC areas. Dehydrogenase activity was different between grass (GB and GWW) and crop areas. The landscape effect was insignificant for enzyme activity. Although soil DNA may be a good indicator of microbial biomass, it did not appear to differentiate among management systems as selectively as other microbial parameters. Results of the study show that establishment of AG, GB, and GWW increased WSA, soil carbon, soil nitrogen, and enzyme activity.
