Decomposition Rates of Wheat Straw Across a Network of Ecosystems

Halstead, S.J., E.A. Paul, K. Paustian, and M. Harmon

Presented at the All Scientist Meeting (1998-07-21 to 1998-07-22 )

The LIDET (Long-Term Intersite Decomposition Experimental Team) project was established in 1990 to examine the role of substrate quality and climatic factors on the decomposition and nutrient release dynamics of fine litter. Wheat straw is one of nine standard litter types distributed across the network of 28 sites, encompassing ecosystems from tundra to desert to tropical forest. Litterbags are retrieved annually for a period of 10 years and mass loss, carbon, nitrogen, and lignin analysis are conducted at Oregon State University (OSU). Data are shared between cooperating sites via an electronic database system managed by OSU.Decomposition rates are lowest in the tundra (Fig 2.1) where both mean annual temperature ( – 2 C) and precipitation (2.4 cm ) are low. The highest rates are in tropical systems (Fig. 2.2) with mean annual temperatures exceeding 24 C, however precipitation ranged from < 2 cm to 21 cm with little effect on decomposition rates. Wheat straw decomposition at the source site, Kellogg Biological Station (Fig. 2.3) is faster than three sites with similar mean annual temperature (Fig. 2.4 – 2.6). The faster decomposition rates at KBS may be attributed to the native microbial fauna and the annual addition of nitrogen fertilizer to the agricultural ecosystem.Return to Contents

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