Since humans began shaping tools to cut, lift, crush, invert, and mix the soil, tillage has become intimately associated with the idea of ‘land husbandry’. The soil’s memory of tillage practices may linger over months, seasons, decades, or millenniums depending on soil texture, structure, drainage, water content, crop rotation, and patterns of rainfall and air temperature. These factors interact with tillage in a complex manner that is often obscured by short-term investigations. Ongoing support for long-term field trials is crucial for assessing tillage effects on soil properties and their relationship to short- and long-term productivity.
In 1984, researchers in NCSU’s Department of Soil Science established two tillage trials, both on fine, kaolinitic, thermic Typic Kanhapludults at the Upper Piedmont Research Station near Reidsville, North Carolina. The Reidsville tillage plots have served as a platform for diverse investigations related to soil-crop productivity and environmental stewardship for over three decades. Eleven research articles have been published in major peer-reviewed scientific journals, and a growing public-private partnership seeks to preserve these unique historic trials for future research.
We present a survey of this research below, sharing insights we have gained about the nature and agronomic importance of tillage in Southern agriculture.
- Long-term Conservation Tillage Effects on Physical Properties and Productivity of Southeastern US Piedmont Ultisols. Jeffrey G. White, Robert D. Walters, Joshua L. Heitman, Adam M. Howard, and Michael G. Wagger. ASA-SSSA 2009 presentation.
- Influence of Tillage on Pore Size Distribution Inferred from Soil Water Retention Curves. Robert D. Walters, Jeffrey G. White, Adam Young, Daniel Morris.
- Tillage Effects on Soil Physical Quality Inferred from Indicators and Pore Volume Density Critical Limits. Robert D. Walters, Jeffrey G. White, and Michael G. Wagger. Second in a series about promising new soil physical quality indicators such as Dexter’s “S-index” that uses information from the soil water retention curve. SSSNC 2014 presentation.
- Tillage Effects on the Distribution of Soil Organic Carbon and Nitrogen in Particle-size Fractions. Samba A. Kawa, Michael G. Wagger, and Robert D. Walters. ASA-SSSA 2010 presentation.
- Soil health: What does it mean in North Carolina? Extension publication AG-439-85. Interpretation of soil health tests conducted at Reidsville and other locations in North Carolina.
- Soil Carbon Sequestration and its Discontents. Agrosphere Journal blog 2017. Discussion of soil carbon sequestration under conventional and conservation tillage in the context of climate change mitigation. A comparative analysis of long-term (23-yr) soil carbon stocks in the Reidsville tillage plots.