Diane E. Stott

Soil biology for resilient, healthy soil

What is a resilient, healthy soil? A resilient soil is capable of recovering from or adapting to stress, and the health of the living/biological component of the soil is crucial for soil resiliency. Soil health is tightly coupled with the concept of soil quality (table 1), and the terms are frequently used interchangeably. The living component of soil or soil biota represents a small fraction (<0.05% dry weight), but it is essential to many soil functions and overall soil quality. Some of these key functions or services for production agriculture are (1) nutrient provision and cycling, (2) pest and pathogen protection, (3) production of growth factors, (4) water availability, and (5) formation of stable aggregates to reduce the risks of soil erosion and increase water infiltration (table 2). Soil resources and their inherent biological communities are the foundation for agricultural production systems that sustain the human population. The rapidly increasing human population is expanding the demand for food, fiber, feed, and fuel, which is stretching the capacity of the soil resource and contributing to soil degradation. Soil degradation decreases a soils production capacity to directly supply human demands and decreases a soils functional capacity to perform numerous critical services, which…

A specimen chamber for soft X-ray spectromicroscopy on aqueous and liquid samples.

A specimen chamber is described for soft X-ray spectromicroscopy of hydrated specimens and solutions. Applications include imaging and carbon edge spectroscopy of hydrated clay/polymer suspensions.

Surface soil quality in five midwestern cropland Conservation Effects Assessment Project watersheds

Soil quality (SQ) assessment is a proactive process for evaluating soil and crop management effects on biological, chemical, and physical indicators of soil health. Our objectives were to evaluate several SQ indicators within five Agricultural Research Service (ARS) experimental watersheds (WS) and determine if those indicators were affected by manure, tillage, or crop rotation histories. Ten soil quality indicators were measured within each of 600 0 to 5 cm (0 to 2 in) depth and 398 5 to 15 cm (2 to 6 in) depth increment samples, evaluated statistically, and then scored using the Soil Management Assessment Framework. Except for soil organic carbon (C) at both depth increments or microbial biomass C and β-glucosidase within the 5 to 15 cm increment, the indicators showed significant WS differences. Except for surface soil-test phosphorous (P), Soil Management Assessment Framework indicator scores and overall soil quality index values also showed significant (p ≤ 0.05) WS differences. Microbial biomass C was significantly affected by crop rotation at both sampling depths and by WS within the surface 5 cm. β-glucosidase was significantly affected by all four factors (WS, manure, tillage, and crop rotation) and their interactions within the 0 to 5 cm increment. The water-stable macroaggregate indictor within the 0 to 5 cm increment and within the 5 to 15 cm increment, however, were not significantly different for the tillage and manure application treatments, respectively. Our study showed that the ARS Conservation Effects Assessment Project (CEAP) watersheds provided a moderately controlled example that watershed-scale monitoring of soil quality is feasible and should be used to monitor soil health and/or conservation program effectiveness.

Soft X-ray spectromicroscopy on hydrated colloidal and environmental science samples

Various aqueous colloidal systems (solid-stabilized oil/water emulsions, clay mineral systems with organics and contaminated estuarine sediment) have been studied with a wet specimen chamber based on silicon nitride windows designed to be used with the Stony Brook scanning transmission X-ray microscope (STXM) [3] at X-1A beamline [8] at the NSLS. The samples were imaged with sub-100 nm spatial resolution at photon energies within the ‘water window,’ employing carbon-K- and calcium-L-absorption edge contrast.

Soil Health: Challenges and Opportunities

In recent years, a broad stakeholder base within the agricultural sector and among the public has become aware of the critical importance of healthy soils, spurred by public awareness campaigns and workshops. As we continue to grapple with a changing climate and more extreme weather events, regenerating the health and proper functioning of our nation’s, and indeed world’s, soil resource will markedly improve the capacity of soil to maintain or increase yield and yield stability, lower input costs, and contribute to other ecosystem services. This is true not only for croplands but also for pastures and native rangelands, orchards, and forests. To aid in moving forward initiatives to help farmers and ranchers improve the soil resource base, the USDA Natural Resources Conservation Service (NRCS) has created a new Soil Health Division (SHD). Personnel distributed across the country will facilitate soil health technical training and education for stakeholders, work with partners to standardize soil health assessments, promote soil health management systems as part of the conservation planning process, and facilitate implementation and long-term adoption of soil health management systems on our nation’s agricultural lands. The new division will leverage skills, resources, technology, and partnerships to achieve these goals.