摘要
Carbon budget changes were measured on a farm near Robinson, Texas, where land originally tilled for hay production was abandoned over time periods of 10, 20, and 35 years followed by succession of prairie and forest vegetation. Woody biomass accumulation increased following abandonment from 0.14 kg C m2 yr~ during forest initiation to 0.57 kg C m2 yr-1 of the mature forest Soil carbon was highest in the tilled field （ 15.77 kg C m2） with lowest in the grassland （ 11.66 kg C m-2）. Soil nitrogen was highest in the tilled field （0.55 kg N ms） and lowest in the forest transition （0.38 kg N m2）. Soil C：N ratios were highest in the forest transition （C：N=36） and lowest in the grassland （C：N=22）. Soil respiration was constant across the site with an annual average value of 1.46 kg CO2-C m-2 yr-. Results show that land in this region may be a source of carbon for several decades following abandonment due to enhanced soil carbon emissions as a function of nutrient input shifts.
