Ditch Soil Research Articles

Morphology and Characterization of Ditch Soils at an Atlantic Coastal Plain Farm

Some materials in drainage ditches that have traditionally been referred to and studied as sediments may be soils. In this study, we described and characterized materials found within agricultural ditches at the University of Maryland Eastern Shore Research Farm (Princess Anne, MD). Sixty‐nine profiles were described in 10 ditches ranging in length from 225 to 550 m. Particle size, pH, and organic C were analyzed on 21 representative profiles. The materials met the definition of a soil in that they supported rooted vegetation. Samples of initial parent material were not collected; however, evidence was observed that horizons had formed through pedogenic processes including organic matter humification and accumulation, structure formation, Fe oxidation and reduction, sulfuricization, sulfidization, translocation, and bioturbation. Ditch soils were generally A horizons formed in loamy alluvial sediments eroded from loess‐derived topsoil over gravelly and sandy C horizons formed in Coastal Plain sediments. Soil structure was described in 75% of A horizons. Redoximorphic features were described in 41% of A and 63% of C horizons. Organic C ranged from 0.4 to 124 g kg−1 Monosulfidic black oozes were observed on some soil surfaces; geological sulfidic materials were observed at depth. Shallow ditches (<1.5 m) tended to have structure and a layer in the substratum with a bright matrix color. Deep ditches (1.5–4 m) tended to have high n value, structureless sola, and Fe‐depleted subsoil horizons. The presence of plants and the operation of pedologic processes may significantly affect ditch ecosystems and environmental functions.

Vertical Distribution of Phosphorus in Agricultural Drainage Ditch Soils

Pedological processes such as gleization and organic matter accumulation may affect the vertical distribution of P within agricultural drainage ditch soils. The objective of this study was to assess the vertical distribution of P as a function of horizonation in ditch soils at the University of Maryland Eastern Shore Research Farm in Princess Anne, Maryland. Twenty-one profiles were sampled from 10 agricultural ditches ranging in length from 225 to 550 m. Horizon samples were analyzed for total P; water-extractable P; Mehlich-3 P; acid ammonium oxalate-extractable P, Fe, and Al (P ox, Fe ox, Al ox); pH; and organic C (n = 126). Total P ranged from 27 to 4882 mg kg(-1), P ox from 4 to 4631 mg kg(-1), Mehlich-3 P from 2 to 401 mg kg(-1), and water-extractable P from 0 to 17 mg kg(-1). Soil-forming processes that result in differences between horizons had a strong relationship with various P fractions and P sorption capacity. Fibric organic horizons at the ditch soil surface had the greatest mean P ox, Fe ox, and Al ox concentrations of any horizon class. Gleyed A horizons had a mean Fe ox concentrations 2.6 times lower than dark A horizons and were significantly lower in total P and P ox. Variation in P due to organic matter accumulation and gleization provide critical insight into short- and long-term dynamics of P in ditch soils and should be accounted for when applying ditch management practices.

Spatial Variation of Soil Phosphorus within a Drainage Ditch Network

Agricultural drainage ditches serve as P transport pathways from fields to surface waters. Little is known about the spatial variation of P at the soil-water interface within ditch networks. We quantified the spatial variation of surficial (0-5 cm) soil P within vegetated agricultural ditches on a farm in Princess Anne, MD with an approximately 30-yr history of poultry litter application. Ditch soils from 10 ditches were sampled at 10-m intervals and analyzed for acid ammonium oxalate-extractable P, Fe, Al (P(ox), Fe(ox), Al(ox)), and pH. These variables were spatially autocorrelated. Oxalate-P (min = 135 mg kg(-1), max = 6919 mg kg(-1), mean = 700 mg kg(-1)) exhibited a high standard deviation across the study area (overall 580 mg kg(-1)) and within individual ditches (maximum 1383 mg kg(-1)). Several ditches contained distinct areas of high P(ox), which were associated with either point- or nonpoint-P sources. Phosphorus was correlated with Al(ox) or Fe(ox) within specific ditches. Across all ditches, Al(ox) (r = 0.80; p < 0.001) was better correlated with P(ox) than was Fe(ox) (r = 0.44; p < 0.001). The high level of spatial variation of soil P observed in this ditch network suggests that spatially distributed sampling may be necessary to target best management practices and to model P transport and fate in ditch networks.

Heavy metal contents and mobility of artificially inundated grasslands along River Weser, Germany

At the beginning of the 20th century municipal wastewater was used to fertilize grassland in the freshwater marsh of the river Weser. In 1987, 150 ha of the marsh became part of a mitigation area with artificial inundation during winter and spring. Heavy metal input may be expected from former wastewater treatment and artificial flooding nowadays. In addition, inundation may increase the availability of heavy metals that were accumulated during municipal wastewater treatment. In order to get an idea of heavy metal content and availability, the content of Cd, Cr, Cu, Ni, Pb, and Zn of the soil, the vegetation, and the input due to inundation were determined. Metal enrichment in the epipedon is evident for Cr, Cu, Pb, and Zn. Total content of Pb and Zn exceed the precaution limit. Soils treated with wastewater seems to contain more heavy metals than the ones without. Inundation causes an input of metals, but it is very low and varies in a broad range. Metal input is higher by atmospheric deposition than the one due to inundation. Degree of enrichment can be arranged in the order: atmospheric deposition > municipal wastewater >> inundation. In shallow ditch soils heavy metals are becoming more available.

Accumulation and consumption of odorous compounds in feedlot soils under aerobic, fermentative, and anaerobic respiratory conditions.

Agricultural odors present an increasingly difficult challenge to livestock producers, yet very little information is available on the microbiology of odor production or microbial factors that regulate the emission of odors. This study examined the microbial potential for odor production and odor consumption in two soils from a cattle production facility in central Nebraska. The two soils tested were collected from a feedlot pen and a runoff ditch below the pen and contained high- and low-fecal matter content, respectively. These soils were tested for their ability to produce and consume a mixture of VFA and aromatic compounds (phenols and indoles) under aerobic, fermentative, and anaerobic respiratory conditions, with NO3-, Fe(III), Mn(IV), and SO4(2-) serving as anaerobic terminal electron acceptors, over a 6-wk incubation. The pen soil had greater (P < 0.05) initial total VFA content (40 micromol/g soil) and produced more VFA during incubation than the feedlot ditch soil, whereas total aromatic compound concentrations were not significantly different between soils. The general pattern of odor compound accumulation and consumption did not differ between soils. Oxygen and nitrate treatments produced very little VFA and consumed acetate more rapidly than the other treatments, which produced large quantities of short-chain VFA and consumed acetate only after all other VFA were consumed. When VFA and aromatic compound consumption was compared across all the treatments, aerobic incubation proved most effective, and all compounds were rapidly consumed by the second day of incubation. Of the anaerobic treatments examined, nitrate proved most effective, followed by Fe, with VFA consumed by d 5 and 21, respectively. Anaerobic incubation with sulfate produced more VFA than the fermentative incubation, and anaerobic incubation with oxidized Mn produced the largest quantities of VFA, which remained high throughout the six-wk incubation. Aromatic compounds were more easily consumed aerobically and were only slowly consumed in the anaerobic treatments. We conclude from this study that cattle feedlot soils possessed a varying, potentially exploitable capacity for odor consumption when alternate electron acceptors were available.

Herbicide Leaching Potential Through Road Ditches in Thin Soils Over an Outwash Aquifer

Shallow glacial outwash aquifers provide water to farms, towns, and major cities. The fact that overlying soils are shallow and provide little protection from leachable chemicals suggests the need for careful management of chemical use. This research was conducted to provide data on the leaching potential of 2,4-D and picloram applied to road ditches over shallow aquifers. A comparison of soil profiles in the ditch and adjoining field indicated that an average of 0.3 m (1 ft) of soil was removed from road ditch soils, leaving very shallow soil profiles over the aquifer material. Cumulative infiltration of water into side slopes and ditch bottoms was measured on representative soils together with gravel road runoff to determine a water balance for the ditch. Undisturbed soil columns were brought into a greenhouse where leaching water could be collected and analyzed for the herbicides, 2,4-D and picloram, the currently used herbicides, which had been applied at recommended rates. The combination of extra leaching water from road runoff added to direct rainfall, and the naturally shallow soils that have been reduced in depth to build the roadbed resulted in two to five times the water passing through to groundwater than through adjoining fields. From 2 to 33% of the applied herbicides came through the undisturbed soil columns after the first storm event. The results indicate that caution should be exercised if the choice is made to use chemical methods of weed control in road ditches.

EDAPHIC AND CROP PRODUCTION CHANGES RESULTING FROM PIPELINE INSTALLATION IN SEMIARID AGRICULTURAL ECOSYSTEMS

The effects of pipeline installation on soil properties and crop production are being documented on three transects (pipe ditch, working side, and control) at four sites (dryland row crop, native pasture, dryland wheat, and irrigated cropland) in Beaver County, Oklahoma. Plant-cover data from the native pasture site show a 37% increase in cover on the pipe ditch during the initial growth season; no significant differences in cover were observed when the control and working side transects were compared. Wheat yield on the pipe ditch at the irrigated crop site was significantly higher, a fact attributed to increased moisture-retention capacity and lower bulk density of the pipe ditch soil. The significantly higher grain sorghum yield on the right-of-way at the dryland row crop site may have resulted from the reclamation practice of chisel plowing the right-of-way on croplands following pipeline construction. Data from the initial sampling and first year of monitoring of the Beaver County sites indicate pipeline installations in semiarid agro-ecosystems have either positive or negligible impacts on soil properties and crop production. 22 refs., 1 fig., 3 tabs.

Environmental radiation from a coal-fired power plant using domestically produced coals.

Environmental samples of ditch soil, ditch water, sea water, and sands were taken from a 280-MWe coal-fired power plant with a daily coal consumption of 2800 tons. Fly and bottom ashes were also taken from the same power plant. A 30 cm3 Ge(Li) detector coupled with a well-shielded and computer-aided multichannel analyzer was used to determine the radionuclides in environmental samples and ashes. Coal samples of North Taiwan with an ash to coal ratio of 1:4 were also investigated. Four major radionuclides of 232Th, 238U, 235U, and 40K were reported assuming the secular equilibrium exists in thorium and uranium series. The annual release of 232Th, 238U, and 235U into atmosphere is 240, 210, and 30 mCi, respectively. Both fly and bottom ashes have highest activity per gram. On the other hand, the 235U content in Taiwan coals, ditch water at the plant site, and sands along the seashore off the plant site is below the detection limit.