Abstract
We investigated the soil carbon budget in a grape orchard (trellis training type) in the Kofu basin, central Japan, from September 1998 to December 2000, and compared it with that in a peach orchard (standing-tree training type). Soil respiration rate (Rs) was measured monthly using the dynamic closed chamber method and annual carbon emission from the soil was estimated using the exponential relationship between the soil surface temperature and the measured Rs. To evaluate carbon supply into the soil, the amounts of litter from grapevines and floor vegetation, applied fertilizer and manure, and dead roots of grapevines were measured or estimated. The total carbon emission and the heterotrophic carbon emission in the grape orchard were estimated to be 422.7 g C m-2 y-1 and 222.5 g C m-2 y-1, respectively, and both values were one half of those in the peach orchard. The total carbon supply was 401.0 g C m-2 y-1 in the grape orchard (litter from floor vegetation 54.5%; litter from grapevine 34%, and fertilizer 11.5%), and was only one-third of the value in the peach orchard. It was determined that carbon from floor vegetation is the largest input to the soil in the grape orchard, which is similar to that in the peach orchard. These results indicate that the grape orchard sequestered carbon of 178.5 g m-2 y-1, which is one third of that in the peach orchard; hence, we suggest that soil in orchards acts as a carbon sink owing to a large amount of carbon input from the floor vegetation.
