Soils of vineyards managed with spontaneous grass cover improve their ability to store organic carbon

Abstract

The endemic scarcity of organic carbon in soils of Spanish woody crops is well known. Excessive tillage mineralizes organic matter and degrades agricultural soils. Soil management through grass covers can replace tillage and increase the soil organic carbon, leading to improvements of soil condition and acting as a more efficient carbon sink. Organic and dissolved carbon (DOC) results are presented in this work, in a vineyard located in the center of Spain; soils have been managed with alternate strips of tilled, and mowed spontaneous grass covers for the last 10 years. The study includes data from 3 soil layers, up to 50cm deep. Changes are evident in the upper layer, by 20cm, where organic matter increases from 1.8 in tilled soils to 2.5% in grassed soils; DOC also increases, from 8.9 to 10.5 mg/L. No significant differences have been detected in the deepest layers (by 35 and 50cm), however, a clear tendency has been observed for DOC to increase in relation to the organic carbon content at 50cm. The movement of DOC to deeper horizons is seen as a new advantage of the grass covers to improve the capacity of carbon sequestration in the long term of these agricultural soils.