Michael Vepraskas

The Soil Science Institute updates the training for mid-career soil scientists to keep them abreast of new developments as well as to review basic soil science concepts in soil physics, soil chemistry, soil microbiology, soil fertility and soil classification. Training during the first week of this 3-week course will be conducted online by NCSU faculty. All faculty conducting the lectures have experience with online instruction. Topics to be covered include soil classification, geomorphology, soil physics, soil fertility, remote sensing, and microbiology. Face-to-face training in weeks 2 and 3 will be at the NCSU campus in Raleigh. Instruction will largely be through lectures with hands-on training to be conducted by two field trips. Week 2 lectures will cover soil chemistry and mineralogy, hydric soils, GIS, sediment an erosion control, and wastewater application. The field trips will be conducted in week 2. For week 3, lecture topics will include tropical soils, animal waste management, organic agriculture, rhizosphere processes, climate change, and forest ecosystems, all taught by NCSU faculty. In addition, USDA lectures will present lectures on coastal zone soil survey, soil health, dynamic soil properties, ground penetrating radar, and urban soils.

Water table levels (saturation periods) in wetlands vary across the wetland and change with soil type and drainage class. These saturation periods have not been determined for most soils, and consequently, hydrologic performance requirements for restored wetlands haven’t been well defined. The main objective of this project is to define saturation periods as a percentage of the growing season that restored wetlands should meet for the specific soils used for restoration. Saturation periods of natural wetlands will be determined for selected soil series ranging from very poorly drained organic soils to moderately well drained mineral soils. Data for most soils will come from prior investigations that measured water tables and computed 40 year records of water table data for each soil. Field monitoring of flood plain soils will also be conducted to complete the data base. Saturation periods for restored wetlands will be obtained from the data base of the NC Department of Environmental Quality which has catalogued water table and soils data from 233 restored sites in NC. Sites having soils similar to the natural sites will be identified, visited to determine soil type at each well location, and to assess wetland condition. Saturation periods will be compared between the restored and natural sites for a given soil type (series and drainage class). Saturation periods for wetlands successfully restored will be proposed for very poorly drained, poorly drained, somewhat poorly drained and moderately well drained classes. These results will allow saturation periods to be estimated for all soils across the region that restoration sites should meet to be successful.

Ecological sites and state-and-transition models (STMs) are rapidly becoming the preferred tool to understand and manage ecosystems in the US and around the world. STMs linked to ecological sites relate plant community dynamics to external drivers as a function of inherent properties of the soil and vegetation. Rangeland health has been linked to the ESD-STM framework for some time; however, as the ESD initiative expands to the more humid ecosystems of the eastern U.S., a complimentary assessment is needed to quantify soil health and general ecosystem function for these landscapes. Many of the rangeland health indicators are also applicable to other ecosystems and can be categorized as dynamic soil properties (DSPs). DSPs change quickly in response to management activities and can serve as indicators of soil health and general ecosystem function. STMs are the backbone of interpreting ESDs, but they are limited by a lack of site-specific information relevant to management. Linkages between STMs and DSPs can improve the development of ESDs and broaden their potential applications. The project team will develop and test ecological site descriptions for three unique southeastern ecosystems and explore the relationships between ecological sites and dynamic soil properties important for quantifying soil health. We will then scale measured soil properties from field measurements to larger spatial extent (e.g., regional extent) using the existing structure of soil survey and the land resource hierarchy. Products generated will include 1) new ecological site descriptions, 2) a “Rapid Assessment Tool” for evaluating ecological state identification, 3) models of dynamic soil properties for specific ecological sites, and 4) selected maps of dynamic soil properties for areas in the southeastern US along with peer-reviewed manuscripts and presentations.

On-site wastewater management systems (OSWMS), commonly referred to as septic systems, are the most common means of treating and disposing of wastewater in areas not served by a sewer system (USEPA, 2002). Approximately half the people living in North Carolina manage their domestic sewage on-site with OSWMS, and it is estimated that 24,000 new systems are being added each year. A conventional OSWMS consists of a septic tank and a drainfield. The septic tank provides primary treatment to the wastewater by allowing solids settle out. After it moves through the septic tank, the wastewater containing dissolved and suspended organic materials, as well as anaerobic biological pollutants (e.g., E. coli), is then infiltrated into the soil through a series of trenches in the drainfield. In the soil, some pathogenic bacteria are removed through physical filtration, and the anaerobic bacteria typically die off in the aerobic soil environment. Studies conducted in NC have shown that 60 cm (2 ft) of aerated, unsaturated sandy soil performs well as a filter for pathogens. In general, for most OSWMS the soil depth needed for holding a septic drainfield and providing filtration below it must be at least 90 cm (3 ft). Such a suitable soil depth is becoming harder to find in the rapidly urbanizing areas of the Piedmont. As a result, there is a greater need to use saprolite (rotten rock) which is porous weathered bedrock that has had many of its original minerals dissolved and removed. Saprolite is found under virtually all soils in the Piedmont and Mountain regions of NC, and in those areas could be used more for OWMS. Saprolite usage for OSWS in the Piedmont and Mountain regions is restricted because it is not known whether this material can remove pathogens as effectively as soil. The objective of this study is to determine if saprolite material can remove pathogens from a simulated wastewater solution that passes through it over distances of 30, 45, and 60 cm. If it can, then saprolite will have the potential to be used for on-site wastewater treatment, and field studies will be the next logical step to verify the findings.

A 3-day class on hydric soil identification is proposed. Each day would consist of morning lectures, and afternoons spent in the field examining soils and installing equipment for hydric soil assessment. Students taking the class will learn: 1) How to describe a soil to determine if it could be a hydric soil; 2) to use the USDA Hydric Soil Field indicators for identifying hydric soils; 3) the chemical and physical processes responsible for creating hydric soils; and 4) how to collect and interpret data on water levels, redox potential, and rainfall to determine if a hydric soil is present at a site. In addition to lecture and field activities, homework will be assigned for students to get more experience in identifying hydric soil field indicators from soil descriptions and in interpreting data.

The objective of this project is to conduct analyses of soil microbial biomass and mineralizable carbon and nitrogen in multiple experiments. The aim it to develop improved nitrogen fertilizer recommendations for forages and other crops. Soil processing and biological analytical techniques will be employed to obtain estimates of soil health and potential nitrogen supply.

NCARS (Cooperator) and the Agricultural Research Service (ARS) desire to enter into this Agreement for the purpose of supporting research to be carried out at ARS and Cooperator facilities. ARS desires the Cooperator to provide goods and services necessary to carry out research of mutual interest within the Plant Science Research unit in Raleigh, NC.

NCARS (Cooperator) and the Agricultural Research Service (ARS) desire to enter into this Agreement for the purpose of supporting research to be carried out at ARS and Cooperator facilities. ARS desires the Cooperator to provide goods and services necessary to carry out research of mutual interest within the Plant Science Research Unit in Raleigh NC. The Location is engaged in research including NP212 Climate Change, Soils, and Emissons. Under the authority of 7 USC 3319a, ARS desires to acquire goods and personnel services from the Cooperator to further agricultural research supporting the independent interests of both parties.

NCARS (Cooperator) and the Agricultural Research Service (ARS) desire to enter into this Agreement for the purpose of supporting research to be carried out at ARS and Cooperator facilities. ARS desires the Cooperator to provide goods and services necessary to carry out research of mutual interest within the Plant Science Research Unit in Raleigh, NC. Research assistant

Wetland restoration is done, in part, to improve water quality. However, in cases where wetlands are restored using agricultural land left high in P from years of fertilization, saturated and reduced soil conditions may cause P to be released from the wetland to nearby surface waters and foster eutrophication. To ensure that wetland restoration and management practices do not contribute to pollution of nutrient sensitive streams, a better understanding of P fluxes into, within and out of wetlands restored from agricultural land is needed. The primary objectives for this study are to: i) determine the change in soil total P (TPsoil) over the 8 years since the study site was restored to wetland, ii) determine P fluxes into and out of the wetland that affect TPsoil, iii) combine objectives i and ii to create a P-balance, and iv) evaluate the accuracy of the P balance by calculating the error in the P-balance, fluxes, and change in P storage. The study will be conducted at a Carolina bay wetland that is representative of most wetlands restored from agricultural land in the southeastern U.S. The research wetland, Juniper Bay, was restored from agricultural soils in 2004 after being cleared of timber, drained, fertilized, and placed under row crop production for up to 30 years. While in agriculture, P accumulated over ten fold in the upper soil horizons of the bay. Research at the site began in 2000 and has continued through the pre- and post restoration processes. During restoration the drainage ditches were plugged and the water table was raised to create wetland hydrology. The site is surrounded by a perimeter ditch which exits the bay at one monitored outflow point. Previous research done prior to restoration showed that the perimeter ditch was effective in collecting ground water inflow to the bay, ground water outflow, and surface water outflow from ditches draining the bay. Our proposed P balance will relate changes in soil TP over an 8 year period to the primary inputs of P to the bay (atmospheric deposition, ground water inflow) and outputs (plant uptake, surface and ground water outflow). Changes in soil TP will be determined over the area of the 256 ha wetland to a depth of 1 m by measuring the difference of TPsoil in archived, pre-restoration samples and present-day soil samples. Fluxes of atmospheric P deposition, plant uptake, and net water outflow (combination of ground water inflow, groundwater outflow, and surface outflow from the perimeter ditch) will be measured for the duration of the study and combined with existing data that has been collected since 2000. Through the development of a P-balance of Juniper Bay, a better understanding will be gained regarding the fluxes of P within and out of wetlands restored from previously farmed and fertilized soils. This increased knowledge will, in turn, improve the ability of restoration professionals to make better management decisions regarding restoration site selection and design, especially with regard to wetland restorations in the Coastal Plain of North Carolina.