Soil carbon sequestration with continuous no-till management of grain cropping systems in the Virginia coastal plain

摘要

Carbon sequestration in agroecosystems represents a significant opportunity to offset a portion of anthropogenic CO emissions. Climatic conditions in the Virginia coastal plain and modern production practices make it possible for high annual photosynthetic CO fixation. There is potential to sequester a substantial amount of C, and concomitantly improve soil quality, with the elimination of tillage for crop production in this region. The objectives of our research were to: (1) measure C sequestration rate with continuous no-till management of grain cropping systems of the Virginia middle coastal plain; (2) determine the influence of biosolids application history on C content and its interaction with tillage management; and (3) evaluate the impact of continuous no-till C stratification as an indicator of soil quality. Samples were collected from 63 sites in production fields using a rotation of corn (Zea mays L.)-wheat (Triticum aestivum L.) or barley (Hordeum vulgare L.)/soybean double-crop (Glysine max L.) across three soil series [Bojac (coarse-loamy, mixed, semiactive, thermic Typic Hapludults), Altavista (fine-loamy, mixed semiactive, thermic Aquic Hapludults), and Kempsville (fine-loamy, siliceous, subactive, thermic Typic Hapludults)] with a history of continuous no-till management ranging from 0 to 14 years. Thirty-two of the sites had a history of biosolids application. Five soil cores were collected at each site from 0-2.5, 2.5-7.5 and 7.5-15cm and analyzed for bulk density and soil C. Bulk density in the 0-2.5cm layer decreased and C stratification ratio (0-2.5cm:7.5-15cm) increased with increasing duration of continuous no-till due to the accumulation of organic matter at the soil surface. A history of biosolids application resulted in an increase of 4.19pl1.93MgChap# (0-15cm). Continuous no-till resulted in the sequestration of 0.308pl0.280MgChap# yrp# (0-15cm). Our results provide quantitative validation of the C sequestration rate and improved soil quality with continuous no-till management in the region using on-farm observations.