Twelve years soil organic components data in the Shenyang National Field Observation and Research Station of Farmland Ecosystems in Northeast China

A long-term conservation tillage field experiment with cropped maize (Zea mays L.) was started in the spring of 2007. The study included three treatments: (1) SM0, straw removal; (2) SM50, mulching with 5.8 t ha⁻¹ yr⁻¹ of maize straw (50% of straw yield); and (3) SM100, mulching with 11.6 t ha⁻¹ yr⁻¹ of maize straw (100% of straw yield). Soil samples from the 0–10 cm layer were collected from the SM0, SM50 and SM100 treatments after maize harvest in the years 2007, 2008, 2009, 2010, 2011, 2012, 2016, and 2019, providing a time series of straw incorporation for 0, 1, 2, 3, 4, 5, 9, and 12 years. Then we measured soil organic carbon, amino sugars, and lignin phenols based on the bulk soil and particle size fractions.