Changes in soil organic carbon storage under grassland as evidenced by changes in sulphur input-output budgets.
Information about temporal changes in soil organic carbon (C) pools may be obtained indirectly from changes in input-output budgets of organically combined nutrients such as sulphur (S). Sulphur budgets were therefore evaluated for Northern Ireland (NI) for the period 1940-1990, inclusive. These budgets indicated that the land or soil had acted first as a sink but then as a source for S, and that reserves of soil S built up between 1940 and 1965 were totally depleted by the mid-1980s. Pooled data from six long-term soil-monitoring sites on undisturbed grassland suggested that negative S budgets from the late-1970s onwards had been due to the net mineralization of soil organic matter and thus were indicative of net losses of organic C from surface soil horizons. There was some evidence that the decline in rainfall and fertiliser S inputs from the mid-1960s may have precipitated the breakdown of soil organic matter.
Department of Agricultural and Environmental Science, The Queen's University of Belfast, UK. john.bailey@dardni.gov.uk
J S
JS
Bailey
Y
Y
Deng
R V
RV
Smith
D000821:Animal Feed; D002244:Carbon / Q000378:metabolism*; D005308:Fertilizers; D009660:Northern Ireland; D006109:Poaceae / Q000378:metabolism*; D011891:Rain; D012987:Soil; D013455:Sulfur / Q000378:metabolism*; D013997:Time Factors
D005308:Fertilizers; D012987:Soil; D013455:Sulfur; D002244:Carbon