Grazing, tilling and canopy effects on carbon dioxide fluxes in a Spanish dehesa

Published source details Uribe C., Inclán R., Hernando L., Román M., Clavero M.A., Roig S. & Miegroet H.V. (2015) Grazing, tilling and canopy effects on carbon dioxide fluxes in a Spanish dehesa. Agroforestry Systems, 89, 305-318.
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This study is summarised as evidence for the following.

	Action	Category
	Soil: Exclude grazers Action Link
	Water: Exclude grazers Action Link

Soil: Exclude grazers

A replicated site comparison in 2008–2010 in shrubland in central Spain found less carbon and nitrogen, and higher carbon dioxide emissions, in soils in ungrazed sites, compared to sheep-and-cattle-grazed sites. Organic matter: There was less carbon in soils in ungrazed sites, compared to grazed sites, in one of two comparisons (in untilled soils: 3.8–9.6 vs 6.5–15.8 Mg C/ha). Nutrients: There was less nitrogen in soils in ungrazed sites, compared to grazed sites, in one of two comparisons (in untilled soils: 0.3–0.7 vs 0.8–1.3 Mg N/ha). Greenhouse gases: More carbon dioxide was lost through soil respiration in ungrazed plots, compared to grazed plots (720–740 vs 640–655 g C/m²/year). Implementation options: Differences in carbon and nitrogen, due to grazing, were found in untilled soils, but not in tilled soils (see above for data on tilled soils). Methods: Eight holm oak Quercus ilex trees were selected in each of two areas grazed by sheep and cattle and in two ungrazed areas. Soils surrounding four trees in each area were tilled in April 2008. Soil respiration was measured nine times in July 2008–February 2010. Soil samples were collected in February 2010 (to measure carbon and nitrogen).
Water: Exclude grazers

A replicated site comparison in 2008–2010 in shrubland in central Spain found less soil moisture in ungrazed plots, compared to sheep-and-cattle-grazed plots. Water availability: Less soil moisture was found in ungrazed plots, compared to grazed plots (4.4–6.5% vs 6.3–7.7%). Methods: Eight holm oak Quercus ilex trees were selected in each of two grazed and two ungrazed areas. Soils surrounding four trees in each area were tilled in April 2008. Soil moisture at 10 cm depth was measured nine times in July 2008–February 2010.