Subject	Agriculture
Specific subject area	Soil carbon and nitrogen, soil carbon sequestration, carbon and nitrogen budgets, nutrient management, vegetable production, long-term organic systems research
Type of data	Table Figure
How data were acquired	Samples of cover crop and vegetable shoots were collected in the field and oven-dried to obtain dry matter. Soil samples were collected in the field and air dried. All samples were analyzed in a laboratory for total carbon and nitrogen using a TruSpec CN analyzer (LECO Corp., Saint Joseph, MI). Soil nitrate concentrations were determined by flow injection photometric analysis of 2.0 N KCl extracts.
Data format	Raw Descriptive Inferential
Parameters for data collection	Factors that vary among systems are cover cropping frequency, cover crop type, cover crop seeding rate, and compost application rate.
Description of data collection	Eight intensive organic vegetable cropping systems were evaluated over an eight year period. Cover crop biomass was sampled in spring prior to incorporation. Vegetables were harvested at maturity by commercial crews. Soils were sampled prior to cover crop planting in fall.
Data source location	Salinas, California, United States of America. lat. 36.622658, long. -121.549172, elevation 37m above sea level.
Data accessibility	With the article
Related research article	White K.E., E.B. Brennan, M.A. Cavigelli, R.F. Smith. 2020. Winter cover crops increase readily decomposable soil carbon, but compost drives total soil carbon during eight years of intensive, organic vegetable production in California. PLoS ONE 15:e0228677.