Filters: Tags: root biomass (X)
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? Rhizodeposition, or the addition of C from roots to soil C pools, is expected to increase if net primary production is stimulated and some excess C is allocated below-ground. We investigated the effects of 5 yrs of elevated CO2 on below-ground C dynamics in a native, C3?C4 grassland ecosystem in Colorado, USA. ? Cylinder harvests following each growing season and monolith excavation at the end of the experiment provided data on root biomass, root C : N ratios, and root and soil ?13C values. We applied an isotopic mixing model to quantify new soil C inputs on elevated and ambient CO2 treatments. ? Root biomass increased by 23% and root C : N ratios increased by 26% after 5 yrs of elevated CO2. Species-specific...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: 13C/12C,
C : N ratio,
New Phytologist,
elevated CO2,
rhizodeposition,
In light of the continuing debate regarding overcompensation we studied the responses of above-ground biomass in a high-elevation, semi-arid grassland to defoliation, defoliation history, and livestock grazing. The above-ground annual net primary productivity (ANPP) was measured over 2 years in one-hundred twenty, 1-m2 plots that were exposed to single- and multi-year defoliation and grazing treatments. Plant communities showed an average increase in ANPP of 31%?45% due to a single defoliation event. The most conservative estimate of average ANPP of defoliated subplots was 29.4 g m?2 greater than the non-defoliated controls. A history of defoliation, due to clipping or grazing, lessened the magnitude of the compensatory...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: ANPP,
Rangeland Ecology & Management,
Society for Range Management,
clipping,
high-elevation grasslands,
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