Abstract Undisturbed land uses have the potential to enhance soil organic matter, but how and to what extent this occurs on private farms remains relatively unexplored. A cross‐sectional study of perennial grasslands and farm woodlots was undertaken across North Carolina to investigate stocks of soil organic C, total soil N, and soil‐test biological activity at 0‐ to 30‐cm depth. Root‐zone enrichment calculations allowed separation of management from pedogenic influences. From a total of 338 fields, total stock and root‐zone enrichment of soil organic C were 6.6 and 3.3 Mg C ha −1 greater under woodland than under grassland, respectively. However, total stock and root‐zone enrichment of soil N were 1.48 and 1.13 Mg N ha −1 lower under woodland than under grassland, respectively. Sand concentration had a large negative association with soil organic C, total soil N, and soil‐test biological activity. Soil C and N properties accumulated with older pastures, however, with modifications based on historical land use prior to grassland establishment. Rotational stocking of beef cattle was associated with greater root‐zone enrichment of soil organic C, total soil N, and soil‐test biological activity. A greater quantity of farm‐level hay feeding was associated with lower levels of soil C and N properties. Results from this on‐farm study revealed clear management influences, but it also showed the complex and confounding nature of multiple management decisions made on private farms, suggesting that large sampling sizes of farms and fields are necessary to make robust interpretations of management impacts at the regional level.
Alan J. Franzluebbers (Sun,) studied this question.