Natural Resources Conservation Service September 14, 2018 – Federal Register Recent Federal Regulation Documents

Notice is hereby given of the intention of NRCS to issue a technical note on a group of recommended standard methods for soil health indicators selected by a collaborative multi-organizational effort, as described in the document. USDA/NRCS and partner efforts to assess soil health problems and impacts of management nationally, as part of conservation planning and implementation, will be facilitated if soil health indicators are measured using a standard set of methods. Soil health is defined as the capacity of the soil to function as a vital living ecosystem to sustain plants, animals, and humans. Six key soil physical and biological processes were identified that must function well in a healthy soil, and therefore would especially benefit from measurement methods standardization: (1) Organic matter dynamics and carbon sequestration, (2) soil structural stability, (3) general microbial activity, (4) C food source, (5) bioavailable N, and (6) microbial community diversity. The chosen methods met several criteria including indicator effectiveness with respect to management sensitivity and process interpretability, ease of use, cost effectiveness, measurement repeatability, and ability to be used for agricultural management decisions. The soil health indicator methods included are soil organic carbon (dry combustion), water-stable aggregation (Mikha and Rice, 2004), short-term mineralizable carbon (Schindelbeck et al., 2016), four enzymes: [beta]-glucosidase (Deng and Popova, 2011), N-acetyl-[beta]-D-glucosaminidase (Deng and Popova, 2011), acid or alkaline phosphatase (Acosta-Mart[iacute]nez and Tabatabai, 2011), and arylsulfatase (Klose et al., 2011), permanganate oxidizable carbon (Schindelbeck et al. 2016), autoclaved citrate extractable (ACE) protein (Schindelbeck et al. 2016), and phospholipid fatty acid analysis (Buyer and Sasser 2012). Standard operating procedures to be used in laboratories have been provided in the appendices.