المستودع الأكاديمي جامعة المدينة

Belowground carbon storage and soil organic matter quality following fertilizer and herbicide applications in ponderosa pine plantations along a site-quality gradient in northern California

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dc.contributor Schoenholtz, Stephen H.
dc.contributor Powers, Robert F.
dc.contributor Perakis, Steven S.
dc.contributor Myrold, David D.
dc.contributor Murphy, Glen E.
dc.contributor Hansen, Eric N.
dc.date 2007-08-15T15:11:43Z
dc.date 2007-08-15T15:11:43Z
dc.date 2007-07-27
dc.date 2007-08-15T15:11:43Z
dc.date.accessioned 2013-10-16T08:08:22Z
dc.date.available 2013-10-16T08:08:22Z
dc.date.issued 2013-10-16
dc.identifier http://hdl.handle.net/1957/6343
dc.identifier.uri http://koha.mediu.edu.my:8181/xmlui/handle/1957/6343
dc.description Graduation date: 2008
dc.description Belowground carbon (C) storage and quality of soil organic matter (SOM) in forest soils have implications for sustainable forest management and C sequestration, but how these pools change in response to management is poorly understood. I investigated whether fertilization and competing vegetation control, applied alone or in combination early in stand development, affected forest-floor, fine-root, and mineral-soil C and nitrogen (N) pools to 1-m depth at three ponderosa pine (Pinus ponderosa) plantations across a site-quality gradient in northern California. Secondly, I assessed how these treatments affected surface SOM quality at these sites via 1) density fractionation, 2) dissolved organic C (DOC) and dissolved N release during 225-day laboratory incubation, and 3) CO2 evolution and DOC mobilization during 16-day laboratory incubation. Twenty years after plantation establishment, mean belowground C pools, were 83, 177, and 206 Mg C ha-1 for the low-, intermediate-, and high-quality sites, respectively. Belowground N pools for the three sites were 5.6, 7.4, and 6.8 Mg N ha-1, respectively. Responses of aboveground biomass to treatment were marked, but changes in belowground C and N pools to fertilization and competing vegetation control were limited. Fertilization increased total C and N pools at the low- and intermediate-quality sites and increased the proportion of total belowground C and N in the forest floor at all three sites. Competing vegetation control increased the forestfloor C pool at the lowest quality site, but had no effect on total pools. Fertilizer increased whole-soil and light-density-fraction N and decreased C:N ratios at two sites, suggesting increased SOM quality. Fertilization decreased C mineralization at the most productive site, had the opposite effect at the intermediate site, and had no effect at the poor site. Competing vegetation control affected light-fraction C and N concentrations and C:N ratios inconsistently among sites and decreased N mineralization at the most productive site, suggesting decreased SOM quality. Although forest floors were the most sensitive of the belowground C pools to these silvicultural treatments, results suggest that the major mechanism for increased C sequestration through management of these ponderosa pine forests will be through increased tree growth, rather than belowground C storage.
dc.language en_US
dc.subject forest soils
dc.subject forest management
dc.subject carbon quality
dc.subject carbon sequestration
dc.title Belowground carbon storage and soil organic matter quality following fertilizer and herbicide applications in ponderosa pine plantations along a site-quality gradient in northern California
dc.type Thesis


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