Restoration is difficult when topsoil and subsoil become mixed during pipeline construction. We studied soil properties, seedling emergence and establishment after pipeline construction in the Rio Grande Plains, Texas following physical (with or without erosion control blanket, ECB), chemical (humic substances, HS), and/or biological (native species mix) treatment. We documented higher soil water following precipitation under ECB; even with ECB soil water evaporated rapidly between rainfall events. Soil temperatures were cooler at mid-day under ECB on sunny days but similar on cool days and during evening. We observed from 3 to 8 more seedlings/0.09 m(2) with ECB. Plots were dominated by exotic grasses after 2 years, likely because of seed bank and seed rain influences. The annual cover crop reduced exotic species biomass but did not negatively impact native species biomass. Pipeline construction affected all soil properties analyzed when compared to adjacent undisturbed areas; many soil properties changed on the pipeline following construction. Humic substances had no measurable effects. ECB enhanced seedling emergence but did not affect 2-year growing season biomass. Recommendations include proper seedbed preparation; ECB during periods of unfavorable conditions; use of locally-adapted species and an annual cover crop; and measures to preclude invasion of non-native species.

Topsoils often are removed from energy production sites and stock-piled for use later in restoration activities. Effects of this practice on soil seed banks are unknown. We examined seed bank size, species richness, and species composition of stock-piled topsoils as affected by sampling depth and sampling date at two study sites in the western Rio Grande Plains, TX, USA. Stock-piled topsoil and adjacent non-disturbed topsoil samples were collected at 0–10, 10–20, 20–30 and 30–40 cm depths on five dates over an 18-month period following stock-pile construction. Seed banks were assessed with the seedling emergence method. Sampling date had little effect on seed bank characteristics. We detected differences among depths on the stock-pile, and between stock-piles and undisturbed soil. Seed bank size and species richness generally decreased with increased stock-pile sampling depth at both sites. Differences between stock-piles and undisturbed soil varied between sites: at one site, stock-piling effects were common and were expressed in lower seed bank size and richness in stock-piles compared to undisturbed soils; at the other site, stock-piling had fewer effects on richness or seed bank size. Prevalence of exotic species varied between sites and likely reflected differences in surrounding vegetation. Therefore, site-to-site variability precludes strong generalizations. However, density of emerged native seedlings ranged from < 1 to 3.8 seedlings m−2 at both sites. Assuming acceptable species composition, stock-piles supported an adequate seed bank size at time of sampling for restoration without need for additional seed input.

Agricultural drainage ditches function as first-order streams and affect nutrient management. Soil mesocosms from a ditch featuring a vertical (increasing upward) gradient in iron (Fe) and phosphorus (P) were subjected to hydraulic and soil treatments. These manipulations mimicked aspects of dredging and controlled drainage and inspected the soil release and retention of P. Treatments did not remove P from simulated groundwater. Throughput water either gained in P (lack of dredging, especially under Fe-reducing conditions) or had P concentrations indistinguishable from input water (dredging). Undredged mesocosms, when Fe-reducing, released Fe and P simultaneously. Simultaneous release of P and Fe from our Fe-reducing mesocosms indicates a mechanism whereby P capture occurs by Fe precipitation upon emergence to aerated surficial waters. Upwelling and surficial phases of ditch hydrology and the lowering of the ditch surface on dredging complicate interpretation of traditional means of describing ditch P retention and release.

The land resource regions (LRRs) I and J encompass much of the southern transition from the forested east to the prairie west. In so doing, the transition is made from udic, to ustic, and in places aridic moisture regimes. Predominant soil orders include Alfisols, Mollisols, and Vertisols. Variation in soil orders is correlated to parent material and vegetation. Mechanisms behind the correlation of Alfisols with oak savannah Oak-savannah and in general tree covered versus prairie landscapes as well as the formation of petrocalcic horizons are discussed. Distinctions between different subregions (Major Land Resource Areas) are emphasized, as well as distinctions with some neighboring LRRs.

Drainage ditch soils mediate nutrient and sediment cycling and transport from ditch-drained agroecosystems. Ditch management may influence the hydromorphology and mineralogy of ditch soils, which in turn may affect their capacity to serve as a nutrient sink. We assessed the effects of hydrologic and soil treatments on ditch soil morphology using mesocosms (15-cm inner diameter, 20–40 cm length) gathered before and after a dredging event. Hydrologic treatments were continuous saturation, continuous field capacity, and an alternating treatment. Soil treatments were organic soil addition, soil removal, and a control. Mesocosms that experienced continuous saturation developed yellower soil matrices and redox concentrations than other experimental mesocosms; this yellowing was interpreted as a loss of paracrystalline ferrihydrite and a retention of goethite. Iron-monosulfides and depletions were more abundant in mesocosms experiencing greater degrees of saturation. The loss of ferrihydrite may indicate reduced P sorption capacity. Colluvial or alluvial materials observed in post-dredged mesocosms indicate the potential of high sediment loss in periods following dredging before vegetation and soil structure establishment.

Agricultural drainage ditches are artificial structures used to optimize soil hydrology for crop production and secondarily have been co-opted as a tool to manage the quality of water draining from agricultural lands. We investigated the relationship between the aquatic macroinvertebrate community and environmental variables associated with physical and biogeochemical processes that affect water quality. Aquatic macroinvertebrates were sampled along with physical and chemical measures of the soil and water from 29 agricultural drainage ditches on the Eastern Shore of Maryland. Cluster analysis and multivariate ordination showed that ditches that had higher flow velocities supported communities of lotic invertebrates (i.e., Stenelmis, Prosimulium) versus those that had properties of linear wetlands, which supported communities of lentic invertebrates (i.e., Oligochaeta, Caecidotea). Taxon richness varied from four to 31 taxa per ditch, and was higher within ditches that had higher flow velocities. Small ditches had low diversity, but may have provided refugia from fish predators. Macroinvertebrate communities did not show a significant linear relationship with water quality or with nutrient concentrations within the soil or water. The addition of flow-control structures designed to improve the quality of water draining from agricultural lands may decrease the quality of ditches as habitat for certain aquatic macroinvertebrates. Management decisions for drainage ditches may consider tradeoffs between the benefits of ditches as a source of biodiversity and as a tool for improving water quality.

Agricultural ditches serve as a major pathway for linking water and nutrients between fields and the Chesapeake Bay on the Delmarva Peninsula. Current projects on ditches focus on management practices to improve nutrient retention and processing. Our goal was to determine if the aquatic macroinvertebrate community can be used to assess the beneficial ecosystem services provided by ditches. Our objectives were to identify the macroinvertebrate community structure within ditches, and to relate the communities to water and soil/substrate conditions. Thirty ditches were sampled during the early spring on the Eastern Shore of Maryland in three counties, representing a range of ditch management practices. Samples were taken from a 100 m section of each ditch. Macroinvertebrates were sampled from 10 sweeps per ditch, combined into one sample. Counts were made to estimate the relative densities of macroinvertebrates, excluding microcrustaceans and nematodes. In addition to the macroinvertebrate sampling, water (pH, conductivity, DO, total solids, TP, TN) and soil (e.g., texture, redox potential, bulk density) parameters were measured within each ditch, along with measures of ditch size, vegetation cover, and other parameters. As examples, cross-sectional areas of ditches ranged from 0.65-6.71 sq. m., conductivity values from 27-297 microS/cm, and dissolved oxygen from 1.0-18.4 mg/L. Macroinvertebrate communities varied from largely annelids to crustaceans to caddisflies, and from relatively simple to diverse communities. Identifications are proceeding now, and multivariate statistics will be used to relate the physical and chemical parameters to the macroinvertebrate communities. By combining expertise in aquatic entomology and soil science, our research presentation will address key aquatic processes within agricultural ditches, and specifically address the potential of using macroinvertebrates as indicators of ecological function of nutrient processing.

The mineral and organic materials in drainage ditches, when stable, may form soils as defined as materials that can support rooted vegetation or form horizons through processes of soil formation. Vegetation in ditches increases sediment retention, Cycles nutrients. and promotes the development of soil structure. Soil-forming processes such as horizon formation, biogeochemical cycling, structure formation, and faunal activity may affect the environmental quality of a ditch and its role in mediating the quality of overlying waters. In ibis paper we provide an overview of soil formation and biogeochemical processes that operate in ditches and discuss the role that these processes have in the mitigation of nutrient and pollutant losses from agriculture. We propose that ditch soil formation is a function of climatic temperature regime, organisms, topography (including the topography of the ditch and the surrounding landscape). bathymetry flow regime, parent material, time, water column attributes, and catastrophic events. Management procedures that encourage ditch vegetation. such as targeted clean-outs and gradual inundation, may increase the stability and ecosystem services of ditch soils. Site assessment and modeling of ditches may be improved by integrating information about ditch soils.

Comprehensive professional development is rarely offered to graduate students, yet would assist students to obtain employment and prosper in their careers. Our objective was to design a course framework to provide professional development training to graduate students that is comprehensive, minimizes faculty workload, and provides enculturation into a single scientific discipline. The course framework is participant-run with faculty facilitation. A pilot course was offered at the University of Maryland College Park in 2004 with eight participants using discussion, writing, reading, and peer-to-peer review methods. The course covered a breadth of professional development subjects with technical writing, manuscript writing, and job search prioritized. Mean participant rating of the overall course was 4.8 (out of 5). Faculty workload was successfully minimized. Discipline enculturation was included in most discussions and readings. We propose that education in a subject be divided into foundation-level and competency-level training. Foundation-level training includes fundamental knowledge and resource awareness. Competency-level training includes the abilities to perform at a level sufficient to obtain and maintain employment and to accurately evaluate the performance of others. Course weaknesses included poor coverage of some fundamentals, some missed deadlines, and variable quality of reviews. These weaknesses may be resolved with improved discipline-specific materials, deadline-based grading, review rubrics, quantitative knowledge assessment and evaluation, and external review for competency-level training. This course framework has potential to offer comprehensive foundation-level training and selective competency-level training to graduate students.