Aquatic Weed Biomass Disposal: Effect on Soil Organic Matter
- Robert L. Tate * and
- Donald N. Riemer
Aquatic weed biomass was amended to field plots of a Freehold sandy loam (Typic Hapludults) either as a mulch or incorporated into the surface soil with the objective of determining the potential for using soil as a repository for excess weed biomass and for using this biomass to augment soil organic matter levels and associated biological processes. Potential and actual dehydrogenase activities, soil organic C, total Kjeldahl N, and the C/N ratio of the soil were measured. Tomato plants (Lycopersicon esculentum Mill.) were grown in the plots. Amendment of the soil with aquatic weeds annually for up to 3 yr resulted in two- to threefold increases in actual and potential dehydrogenase and total Kjeldahl N. No consistent effect of inclusion of nitrogenous fertilizer with the aquatic weed amendments was detected. Analysis of the data with multiple linear regression techniques indicated that total Kjeldahl N and soil moisture were major controllers of both potential and actual dehydrogenase activities. This study suggests that aquatic weeds, whether added as a mulch or incorporated into the surface of the soil profile, have little effect on soil C, at least in the short run, but have a positive impact on the ecosystem through augmentation of the soil organic N pools and increased microbial activity.
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