Abstract: Conservation practices are designed to reduce losses of soil, nutrients, pesticides, pathogens, and other biological and chemical materials from agricultural lands, conserve natural resources, enhance the quality of the agro-ecosystem, and enhance wildlife habitat. The Farm Security and Rural Investment Act of 2002—referred to as the 2002 farm bill—substantially increased funding levels of conservation programs—up nearly 80 percent above the level set for conservation under the 1996 farm bill. While it is widely recognized that these conservation programs will protect millions of acres, the environmental benefits have not previously been quantified for reporting at the national scale. Moreover, while an extensive body of literature exists on the effects of conservation practices at the field level, there are few research studies designed to measure the larger effects. The Natural Resources Conservation Service (NRCS) and the Agricultural Research Service (ARS) are working together on the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of conservation practice at the national and watershedscales as a measure for how the money being spent is meeting the goals. CEAP is an on-going mix of data collection, model development, model application, and research. One of the goals is to dovelop the …

Abstract: Row-crop agriculture, continuous-grazing, and stream channelization, have accelerated stream bank erosion and increased sediment load. Stream bank erosion rates and total soil loss were compared among riparian forest buffers, row-crop fields and continuously grazed pastures along a continuous 11 km (6.8 mi) stream reach in central Iowa. Exposed erosion pins were measured to estimate stream bank erosion rates, approximately every month from June 1998 to June 1999, except during the winter months. Total stream bank soil losses for each treatment were estimated from the mean bank erosion rate, mean bulk density, and the total stream bank eroding area. Row-crop fields had the greatest stream bank erosion rate and total soil losses followed by continuously grazed pastures while riparian forest buffers had the lowest. If riparian forest buffers had been established along all of the non-buffered segments of the 11 km (6.8 mi) stream reach, total stream bank soil loss would have been reduced by approximately 72%.

Abstract: Control of soil erosion and associated nonpoint source pollution is essential to improving water quality. The use of compost or mulch blankets as a soil cover can help control soil erosion and provide sustainable alternatives to disposal for many biomass resources. The objective of this study was to investigate the amounts of runoff, erosion, and nutrient losses obtained under simulated rainfall using a variety of compost and mulch materials. Treatments included aged poultry litter, two different types of poultry litter compost, municipal solid waste compost, biosolids compost, food waste compost, yard waste compost, three different types of wood mulch, and bare soil. Results indicated that all of the treatments except for aged poultry litter were effective at reducing total solids loss in the runoff. Nutrient losses from most of the compost treatments, however, were higher than those from bare soil or mulch treatments. Treatments with lower respiration rates and nitrate-nitrogen concentrations tended to have less erosion and transport of solids. Nitrate-nitrogen content, respiration rates, soluble salt, sodium, and potassium contents were good indicators of ammonium and phosphorus losses.

Abstract: Measurement of crop residue cover over large areas is useful for monitoring conservation tillage adoption, assessing carbon sequestration potential and erosion modeling. This study was designed to test the accuracy of crop residue estimates in current Tillage Transect Surveys, and to test the feasibility of predicting crop residue cover based on data recorded by Landsat Enhanced Thematic Mapper Plus (ETM+) satellite scenes. A total of 468 corn and/or soybean fields in 11 Minnesota counties were characterized for residue cover in the course of three sampling campaigns coinciding in time with satellite scene acquisition. Results showed that Tillage Transect Survey estimates were correct for 49 percent to 74 percent of fields when either five or two categories were used in classification respectively. Regression analysis showed a strong positive relationship between percent soybean residue cover and ETM+ bands 1, 3, and 7 (r 2 =0.66) and between percent corn residue and ETM+ bands 4, 5 and 7 (r 2 = 0.44). Three additional indices based on satellite digital numbers, the Soil Tillage Index, Normalized Difference Index, and Normalized Difference Tillage Index had coefficients of determination between 0.02 and 0.56 for corn and soybean residues. The Crop Residue Index Multiband model, a more physically based model, correctly predicted residue cover categories for 30 to 64 percent of fields when five or two categories were used in classification respectively. We conclude that remote-sensing techniques had accuracy as good or better than Tillage Transect Surveys estimates when residue cover classifications were decreased to two categories (o to 30 percent, and >30 percent). Since residue cover information is primarily needed to assess the extent of two categories, conservation and conventional tillage, remote sensing with Landsat imagery provides a means of sampling every field with an efficient, economical and uniform methodology.

Abstract: Reducing and off setting anthropogenic emission of CO2 by fossil fuel combustion is a major global issue because of the threat of climate change associated with rapid increase in atmospheric concentration of carbon dioxide (CO2). Renewable sources of energy and production of biofuel energy is an important strategy of global significance for reducing CO2 from the atmosphere. In 1999, President Clinton called for the United States to increase annual energy production from renewable resources by 2030 (Federal Register, 1999). In 2003, President George W. Bush set a national goal to reduce greenhouse gas intensity of the U.S. economy by 18 percent by 2012 (U.S. Department of State, 2003). The greenhouse gas intensity is defined as the ratio of the greenhouse gas emitted (expressed as C equivalent) per real gross domestic product. Consequently, the importance of bioenergy is widely recognized, and the sources of biomass to be used as a feedstock for biofuel production are being enthusiastically pursued. It is in this regard that crop residues are being considered as a potential feedstock for bioenergy production. To be economically and ecologically viable, gains in energy from a potential biomass source must outweigh the energy use in production and collation …

Abstract: Changing climate across the United States has been observed in the increasing intensity and amount of precipitation. One of the predicted areas for this impact is in the upper Midwest or the Corn Belt, and one concern is that current soil management practices in this region may not adequately protect the soil under these changes resulting in water quality impacts. To address this concern, this study was conducted to survey the current literature on the water quality impacts from current soil management practices and evaluate potential impacts on runoff and drainage from soil management practices under a number of precipitation scenarios. Soil management practices, e.g., crop residue, no-till, incorporation of manure, provide protection under today9s climate. However, increasing precipitation amounts, or frequencies, rapidly decrease the effectiveness of these practices with the deleterious effect being even greater on soils with low water holding capacity and limited depth. The water quality impacts may be even more dramatic with the likelihood of increased surface runoff events. Soil management practices need to be developed and evaluated under precipitation patterns that may represent future scenarios so that producers can begin to adopt these practices into their management programs.

Abstract: Little is known about the impact of tillage methods on soil movement resulting from hoeing tillage operations in the Sichuan Basin, China. Effects of tiered ridge and contour tillage on soil movement (translocation and erosion) were examined in the steep hillslopes of this basin using a physical tracer method. Stone chips were used as tracers, having a contrasting color from the surrounding soil, and were incorporated into each experimental plot. Net mean downslope displacement distance by contour tillage was much shorter (P<0.0001) than that by downslope tillage (5 times for tiered ridge tillage, 3 times for flat tillage). Soil displacement distance was positively correlated to slope gradient for downslope tillage (R2 = 0.6303 – 0.8282, P = 0.0002 – <0.0001), whereas slope gradient was not significantly correlated to soil downslope displacement by contour tillage (R2 = 0.2421-0.3142, P = 0.0529-0.0239). Tillage transport coefficients were 25.5 and 30.7 kg m−1 tillage pass−1 for k3-values and 153.0 and 141.3 kg m−1 tillage pass−1 for k4-values, respectively for downslope ridge and downslope flat tillage. For a typical downslope length of 15 m and two tillages per year, tillage erosion rates by downslope tillage reached 42.0 - 129.1 t ha−1 yr−1 and 49.0 - 122.1 t ha−1 yr−1 for slopes ranging from 0.04-0.47 m m−1 and from 0.04-0.43 m m−1 respectively for downslope ridge and downslope flat tillage. Tillage erosion rates by contour tillage were reduced by 84% and 77%, compared to downslope tillage respectively for ridge and flat treatments. No significant differences in soil translocation and erosion rates existed between downslope ridge and downslope flat tillage. Contour ridge tillage was more effective than contour flat tillage with respect to controlling tillage translocation and erosion.

Abstract: Computer based frameworks, including geographical information systems (GIS), associated digital data sets and integrated hydrological models, have become essential tools for the practical deployment of watershed assessment projects and ultimately for providing support for water quality protection and conservation. Within these frameworks digital soil information and data sets play a key role in defining the spatial distribution of important hydraulic variables and consequently of fundamental hydrologic functions connected with NPSs (Nonpoint Sources) and their modeling. This paper illustrates background and results from the development of a GIS based tool required for the use of Soil Survey Geographic (SSURGO) data sets (an undergoing development and delivery effort of digital soil maps by the Natural Resources Conservation Service) and primarily designed in specific support of the Soil and Water Assessment Tool (SWAT) model and its applications in the United States. The tool is developed as an addition or extension to the model companion, the ArcView GIS interface in its latest version (AVSWAT-X) which is designed to define watershed hydrologic features; store, organize, and manipulate the related spatial and tabular data; and analyze management scenarios. Within this framework the tool expedites the otherwise complex inclusion operations of the SSURGO data, such as: (1) downloading, via the Internet, up-to-date SSURGO data sets (version I or II); (2) processing and managing variously formatted data sets in order to create the needed digital soil maps; (3) generating and/or storing the required soil physical and hydraulic model input parameters derived from pedo-transfer functions; and (4) seamlessly including them in any watershed modeling framework. Besides the operational advantages, the tool addresses the trend of employing soil maps with increasing detail in order to improve the landscape representation and reduce the modeling drawbacks involved with the aggregation of the spatial input. Soil map features with unprecedented detail along with the elaborated attributes have a potential for enhancing modeling assessments in support of water quality programs (i.e. Total Maximum Daily Load) at the watershed as well as stream reach scale, as indicated in basic yet important highlights in the paper.

Abstract: The relationships between the soil erosion of phaeozem in the northeast region of china and humus, soil parent material, climatic condition, land feature, vegetation and man′s activity in this area have been analyzed. It has been pointed out that the reclamation on a large scale in the phaeozem region is the primary reason causing soil erosion in this place, and at the same time, several natural factors that are the potential factors to affect soil erosion have played more significance role in accelerated erosion after human broke into the phaeozem region. In fact, the phaeozem region of northeast China has became the most hazard region of potential erosion now for it′s unique physical geography environment and man′s activity. At present, the phaeozem region is subjected to severely soil erosion and at somewhere the loess mother material is exposing to the air. So we must action now to explore the law of soil erosion and to cure the soil erosion using this law, or else, the phaeozem region of northeast China will became the real barren land.

Abstract: Integrated Geographical Information System(GIS) with Universal Soil Loss Equation(USLE),soil loss was predicted and risk areas of soil erosion were identified in Jiulong river watershed. Reasonable methods were adopted to obtain R, LS , K , C, P factors value. Results showed annual average soil erosion amount was 2 730. 3 t/ km~2 and it was in the category of middle degree erosion. The serious eroded area(sediment yield is higher than 5 000 t/km~2) only occupied 14. 28% of area, but contributed 41. 74 % of sediments in the watershed , while no or slightly eroded area(sediment yield is lower than 5 000 t/km~2) was 85. 72% of area, but contributed 58. 26% of sediments. The annual average soil erosion was higher in Chuanchang river, Huashan river, and Yanshi river sub- watersheds. The annual average soil erosion was lower in Longhai and Punan segment in North river sub-water- sheds.

Abstract: Millions of dollars have been spent on agricultural watershed projects across the nation, but little is known about the long-term impacts of watershed management and protection efforts. Information pertaining to long-term condition and water quality impact of best management practices (BMPs) is scarce. Evaluation methods that estimate the current condition of the practice based on visual inspection and comparison to selected original design dimensions were developed for grassed waterways, grade stabilization structures, field borders and parallel terraces. The evaluation tools were tested for validity using an expert panel approach and for reliability based on inter-rater correlation. The evaluation tool9s three-point scale rating system assigns a score of three to a BMP that was fully functional and still met its original design purpose and a score of one to a BMP that no longer performed as designed. The newly developed evaluation tools were applied to a subset of structural BMPs implemented in the late 1970s in a major watershed management project in an Indiana watershed. One-third of the BMPs no longer remain. Those BMPs that remain today are in fair condition and are reasonably functional. Grassed waterways and terraces were most likely to remain, while the field borders that still existed had the highest condition score. This study suggests that BMPs can in some cases continue to function past their design life, but serves as a reminder that BMP functional life is limited, a fact that needs to be explicitly considered in conservation and watershed planning.

Abstract: A community-based adaptive management framework is applied to the Calapooya Creek, Deer Creek, and Myrtle Creek watersheds within the Umpqua River Basin in Southwestern Oregon. The objectives are to: 1) identify agricultural landowner participation in watershed conservation projects, and 2) determine the characteristics of participating and nonparticipating landowners. Data are derived from a 1998 landowner mail survey with a 53% response rate. Landowners implement upland conservation practices such as off-stream livestock water developments and rotational grazing more often than riparian fencing, riparian tree planting, and installing fish screens on irrigation diversions. The key factors in adoption of conservation practices include the use of irrigation, shared management decisions with a spouse, a belief in scientific experimentation, and discussion of conservation with others. The key factors predicting adoption of best management practices depended on the kind of best management practice implemented.

Abstract: The impact of Land Use and Land-Cover Change (LUCC) mainly on annual runoff yield, in this study through scenarios simulation of Lushi basin using SWAT(Soil and Water Assessment Tools), the impact of LUUC on annual runoff yield and sediment yield were analyzed, and stressed on the forest's impact on runoff yield. The subbasin upper to the Lushi hydrologic station in the lower reach of the Yellow River basin, the daily precipitation data of 24 rainfall station and the climatic data in this area from 1992~2000, soil type and the scenarios of the landuse, all of these data were inputed to the SWAT (Soil and Water Assessment Tool ) to simulate the impact of LUCC on the yield of runoff and sediment. The simulated results indicate that forest will increase the runoff yield and decrease sediment yield, grassland reduce runoff yield; with the increase of land use of agriculture the sediment yield will increase correspondingly; the least impact of LUCC on runoff yield was found in normal mean precipitation year, with the increase of the rain rate, impact of the basin condition on the runoff and sediment yield will be reduced.

Abstract: Nitrogen (N) contamination of surface and groundwater is a health concern for both humans and animals. Excess nitrogen in surface water bodies may contribute to eutrophication. Elevated nitrate (NO3-N) concentrations in drinking water have caused infant death from the disease methemoglobinemia. Formation of potentially carcinogenic nitrosamines in the soil from nitrite (NO2-N) and secondary amines is also a health concern. Both NO3-N and NO2-N have been shown to negatively affect the metabolism of domestic animals. Movement of NO3-N and NO2-N to groundwater is of particular concern in the southeastern Coastal Plain because of the unique climatic, soil morphology, and geohydrologic regimes of the region. Climatically, the southeastern Coastal Plain is characterized by warm temperatures and relatively high rainfall. Because of the extended growing season, multicropping, which requires multiple applications of nitrogen, is commonly practiced. Annual rainfall distribution often also requires use of supplemental irrigation. The combination of relatively high nitrogen inputs, high rainfall, and use of irrigation for crop production coupled with areas of permeable sandy-textured soils and geologic materials means that large portions of the coastal plain may have high potential for nitrogen contamination of surface and ground waters. Research at the Southeast Watershed Research Laboratory (SEWRL), USDA-ARS, in cooperation with the University of Georgia over the past 20 years has focused on determining factors affecting nitrogen transport and transport rates over a range of coastal plain soils and management scenarios. This paper examines the findings from these extensive studies, reports new findings from a long term study, and synthesizes all information to examine the long-term implications for nitrogen contamination of soil and water from agriculture in the southeastern Coastal Plain.

Abstract: Pine needles (straw) are an attractive landscape mulching material that protects the soil surface against erosion, conserves soil moisture, moderates soil temperature, and inhibits weed growth; yet it retains a loose, open structure that allows air, fertilizer, and water to easily penetrate the soil surface. Such characteristics have made pine straw a valuable commodity, but the loss of those mulching benefits from pine forests has raised concerns about effects on watersheds where pine straw is harvested. For example, pine straw absorbs the impact of raindrops and slows the speed of runoff, so its removal may increase soil erosion and nutrient losses, and decrease water-holding capacity of the forest floor. To test this hypothesis, three pine-straw harvesting practices and a control treatment (no straw harvest) were compared to determine harvesting effects on water, soil, and nutrient losses in runoff. The 24 plots (six replications of each treatment) were constructed in an established (16 yrs) loblolly pine (Pinus taeda L.) stand that had tree spacing of 3.0 m by 1.5 m (10 ft by 5 ft), and basal area of 41.3 m2 ha−1 (180 ft2 ac−1). Each plot (2 m by 1 m or 6.6 ft by 3.3 ft) had four percent slope, aluminum borders, and a runoff collector. Simulated rainfall was applied [5 cm h−1 (2 in h−1)] to produce 20 minutes of runoff from each plot. Annual pine straw harvesting clearly increased runoff, soil erosion from 0.5 to 91.6 kg ha−1 (0.4 to 81.7 Ib ac−1), and losses of phosphorus (P), carbon (C), and total Kjeldahl nitrogen (N) in runoff; but these losses were partially controlled by less-frequent harvesting, and declined to control levels when pine straw had accumulated for two years.

Abstract: In a semiarid-to-subhumid region, water use by crop species can have a considerable impact on both crop production and soil landscape hydrology Crop production following high water-using crops can be decreased while ephemeral streams and wetlands can be increased by growing lower water-using crops Water use and soil water depletion were determined with neutron moisture meters in ten crop species (barley, canola, crambe, dry bean, dry pea, flax, safflower, spring wheat, soybean and sunflower) for two years, and measurements are presented for four of these species for one additional year The observations were made in various species which were grown after spring wheat during crop sequence experiments Sunflower was the greatest water user, followed by safflower and soybean Dry pea was the lowest water user, followed in order by barley, crambe, and spring wheat During an above average precipitation year, the depth distribution of soil water depletion among canola, dry pea, spring wheat, and sunflower was similar In contrast, during a year of relatively low seasonal precipitation, differences were evident among the four crop species Sunflower and canola extracted 49 percent and 45 percent of their soil water depletion, respectively, from soil depths greater than 60 cm, while spring wheat and dry pea extracted 33 percent and 27 percent of their soil water depletion from below 60 cm depth Using a three-year dataset, it was found that water use and soil water depletion were highly correlated with seasonal precipitation, significantly correlated with median depth of water depletion and days from seeding to harvest, but not correlated with root growth parameters As a general guide to water use by crop species, length of active growing season appears to be the most important factor

Abstract: Methods for mapping hydrologic variables to locate vegetated riparian buffers were explored using examples from the Deep Loess Region of the Midwest. Elevation and stream-flow data were used to define wetness, baseflow, sediment transport, and discharge indices. Groundwater dominates discharge in very small streams and through riparian areas in the region. All indices showed that riparian areas along first order streams have greater potential to intercept groundwater or runoff than similar areas along larger streams. A wetness index, used to indicate saturated soils, defined a significantly (p<0.05) greater probability of saturation along smaller streams, enhancing the potential for groundwater interception. Significantly smaller values of the sediment transport index along smaller streams provide enhanced opportunities for deposition of sediment and associated contaminants. A discharge index shows that buffers along first order streams have orders of magnitude greater opportunities to intercept water passing through riparian areas than reaches of larger streams.

Abstract: A growing concern over water quality in agricultural areas highlights phosphorus (P) as a key constituent in eutrophication and degrading water quality. A preliminary analysis is presented that tests the effectiveness of P index predictions using linkages to sediment and surface water P concentrations. The field P status in the Elk Creek watershed is described according to P inputs by land managers, soil characteristics, and sediment and water quality analyses. The watershed is partitioned into contributing areas, and the available P in soils shows an increase in concentration in the downstream direction. The P index ratings also show an increase in vulnerability for P loss from soil to surface waters in the lower part of the watershed. The rankings are in agreement with the intensity of land use, and this is reflected in the increase in predominance of the source factors as the main contributor to the P index ratings. In spite of complex process interaction associated with sediment movement, the stream sediment showed similar trends to the soils and P index ratings. Increases in total P in wetseason stream water at the outlet of the watershed may indicate the downstream cumulative effects predicted by the P index ratings.

Abstract: The soils and landscape of the Columbia Plateau in eastern Washington and northeastern Oregon have developed primarily as a result of redistribution of glacial outwash sediments by wind. Contemporary agricultural disturbance of regional soils facilitates wind erosion that impairs downwind air quality by the introduction into the atmosphere of large quantities of particulate aerosols less than 10 microns in aerodynamic diameter (PM10). Reducing these agricultural contributions to PM10 concentrations in urban areas has been identified as a critical component of regional compliance under the Clean Air Act. We designed a sampling and analysis scheme to develop empirical relationships first between total mass flux during wind tunnel erosion trials and soil aggregate size distributions; and second between soil PM10 emission potentials and primary particle size distributions. We then applied those empirical relationships to predict potential total soil erodibility and potential PM10 emissions at a larger set of field soil sample sites. The resultant point predictions were interpolated spatially using geostatistical methods to generate a prediction map of PM10 emissions hazard, which is similar to the U.S. Department of Agriculture (USDA) Farm Services Agency map of air quality conservation priority areas for the Columbia Plateau.

Abstract: In recent years, nonpoint source pollution (NPS) has been recognized as one of the major threats to the nation9s water quality. Clearly, forest operations such as harvesting and site preparation have the potential to have degrading impacts on forest water quality. However, there exists a gap in the understanding of the nature and extent of NPS pollution problems related to forest operations. The study presented here was performed in Lee County, Alabama to investigate the impact of clear-cut harvesting and mechanical site preparation on a 20-year-old loblolly pine (Pinus taeda L.) plantation on sediment and runoff yield. Sediment and runoff yield responses on treated areas were compared to that of undisturbed areas. Impacts were evaluated by monitoring isolated small plots, 2 m (6.6 ft) by 5.5 m (18 ft), over a two-year period following the harvest prescription. Sediment yield from the control treatment was 0.11 t/ha (0.30 ton/acre) over the study period. Sediment yield increases of 0.11 t/ha (0.30 t/ac) and 1.3 t/ha (3.5 t/ac) were observed from clear cut harvest/site prep/plant (H-SP-P) treatment and clear cut harvest /plant (H-P) treatment, respectively. However, erosion losses from the most erosive treatment, clear cut harvest /plant, was still very low at less than 1 t/ha/.yr. Runoff yield results were similar to those observed with sediment yields from treatments in the investigation. Differences in the two treatments were likely due to the differences in surface roughness, which affects infiltration and surface flow velocity.

Abstract: A methodology of determining regional estimates of Conservation Reserve Program (CRP) areas required to achieve a given percentage reduction of localized agricultural sediment yield is introduced. Using South Dakota as a test domain, a collection of regional-scale databases was used to compile a statewide erosion vulnerability map based on Universal Soil Loss Equation (USLE) factors. This was then arranged into climate, erosion risk, soil and topographic zones. Statistical procedures were then employed to extract predominant input values required for the U.S. Department of Agriculture (USDA) Water Erosion Prediction Project (WEPP) model applicable to each of these zones. WEPP simulations using these inputs provided estimates of grass buffer strip areas required to achieve targeted percentage reductions of sediment yield in each of these zones. The response of each of these zones towards employment of grass buffer was found to vary considerably. Comparison with small-scale field studies suggest that the WEPP model can be used to measure efficiency of grass buffer strips in different zones. This approach demonstrates how regional analyses using factor-based erosion models can be combined effectively with process-based field-scale erosion models to provide viable estimates of sediment reduction due to adoption of CRP-type grass buffer strip practices.

Abstract: As a fragile factor of karst ecosystem, karst underground water system is highly sensitive to landuse change. Taking Houzhai subterranean stream basin, Puding County, Guizhou Province as an example. The im- pacts of intensity of agriculture activities, landuse change and irrigation system change upon underground water were analyzed based on more than 20 years' hydrochemical data. The results showed that both intensification of a- griculture activities, landuse change and irrigation system change can bring spatial and temporal change of under- ground water quality. Some are beneficial, such as co-irrigation of ground and underground reservoirs, vegetation planting(from farmland to forest); others are disbeneficial, such as urbanization, direct discharge of waste, and overuse of pesticide and fertilizer. Accordingly, underground water vulnerability should be considered during the landuse planning, thus help the harmonious development between human activities and resources and environ- ment.

Abstract: For erosion experiments in the field where no electric power is available an automated device for runoff and soil loss measurements was developed. This equipment is designed for continuous runoff measurement from plots up to 6om2. The design is similar to a turning wheel with a horizontal axle. The automated erosion wheel (AEW) consists of four equal sections each one holding five liters (1.32 gal) resulting in a resolution for each tip of 0.08 mm (0.003 in) for 6om2 plots. The automated erosion wheel is capable of measuring a maximum rate of 75L min−1 (19.81 gal min−1). Each tip is monitored automatically in real time by a data acquisition system. Up to three automated erosion wheels can be connected to one data logger. The whole system is powered by one solar panel. Soil-water-suspension is divided by an adapted multi-tube divisor. About 3.4% of the runoff is sampled in a plastic barrel for determination of sediment concentration and soil loss. At this stage no temporal distribution of sediment delivery can be recorded by the automated erosion wheel. After each erosive rain storm, collectors are emptied and samples are taken to the lab for further analyses. With calibration of the tipping buckets volumes an accurate, time distributed runoff measurement is possible. The maximum error in sediment concentration measurement is 1.1%. Therefore, the chosen multitube device is able to collect representative runoff samples containing same sediment concentration as surface runoff. Each automated erosion wheel system is located in a shed. The automated erosion wheel has been used at three locations in Austria since 1997.

Abstract: The study results of the content variation of organic carbon and its component in black soil during different tillage period show that both the content of TOC and its component decreasing and the soil Kos value increasing in ploughing layer and ploughing bottom layer are rapid at first 50 years cultivation. After 130 years tillage, the content of organic carbon and its component are relative stable on the whole. Total organism carbon content in ploughing layer of black soil lost 1.76%~24.81% after 200 years tillage. Among organic carbon component, the FA-C is affected relative little by tillage time, while Hu-C is affected seriously.

Abstract: Nitrogen (N) is difficult to manage because of its dynamic nature and mobility. Improving N use efficiency in agricultural production requires better accounting of N sources and sinks. In small grain [barley (Hordeum vulgare l.) and wheat (Triticum aestivum l.)]-potato (Solanum tuberosum l.) systems, N cycling from small grain crop residue into potato crops is poorly understood. We used 15N labeled fertilizer to trace N from the small grain crop residue into a potato crop. We found that the 15N recovery by these small grains averaged about 46 percent. When we factored in the soil 15N recovery, the average 15N recovery in the system was about 70 percent. The cycling of N from the crop residue into the potato averaged about 2.6 kg N ha−1 for wheat and 4.4 kg N ha−1 for barley. We estimate that the total N cycling from the above ground and below ground compartments was about 4 to 9 kg N ha−1 and that total N released from the crop exchange residue, including the unaccounted N, was about 9 kg N ha−1. About 82 to 86 percent of the N that was incorporated with the crop residue was still in the system (soilcrop) after one year of cycling, which suggests that considerable N is sequestered in the soil over that time period. Results highlight the importance of crop residue in N cycling and identify opportunities to improve the assessment of N budgets for commercial small grain-potato operations.

Abstract: Phosphorus (P) based nutrient management regulations may affect the viability of agricultural enterprises in Pennsylvania. Identification of areas likely to be affected by impending P-based regulations will allow regulators and conservation officials to better target technical and financial assistance. A statewide GIS analysis based on an extensive soil testing database and available geospatial data (including land cover, streams, and livestock density) found that various regions of Pennsylvania would be affected by the P-index restrictions for different reasons. In the southeast and parts of the northeast, high soil test P levels associated with intensive animal agriculture required a full assessment of P source and transport factors under the P-index. In north- and south-central and southwest Pennsylvania, the P-index assessment was required because of the proximity of much of the region9s farmland to surface waters. Additionally, nearly half of agronomic soil samples exceeded the optimum P level for crops, suggesting widespread over fertilization and an ongoing build up of soil P stocks. Soil P was found to increase with increasing animal density and the highest animal density areas had a large number of nutrient impaired streams. When samples were separated based on cover type, croplands exhibited the highest P levels, followed by grasslands and then pastures. Finally, a weighted combination of the percentage of soil samples exceeding 200 ppm P and the proportion of agricultural lands within 150 ft (45.7 m) of streams indicated that southeastern Pennsylvania, especially Lancaster County, would be most affected. How farm operators adapt to P-based nutrient management, via on- and off-farm strategies, will determine the severity of the impact and the necessity of government assistance.

Abstract: Adoption of conservation tillage for corn (Zea mays L.) and soybean (Glycine max L.) rotations, has stagnated over the past several years despite the evidence of the benefits to erosion control, soil health, and associated natural resources derived from conservation tillage. The Monsanto Centers of Excellence were established to evaluate the potential benefits of conservation tillage across a range of soils and climates. Our objective is to summarize the results from field-scale studies conducted at 13 Monsanto Centers of Excellence sites in nine states from 1998 through 2002. Strip-tillage, no-tillage, and conventional corn production, and narrow- and wide-row, no-tillage and conventional tillage soybean production were evaluated in this study. Nine of the 13 sites included a stale seedbed “fast start” corn treatment by which the seedbed is prepared in the fall by conventional tillage and a spring herbicide burndown if needed. Neither soil bulk density nor crop emergence showed any significant differences among tillage systems for either crop throughout the five-year study. Earthworm populations were higher with no-tillage than conventional tillage. Soil quality indicators were not significantly different among the tillage systems. Soil temperature at the 5 cm depth was similar for strip-and conventional-tillage, with both being higher than no-tillage Yield differences among tillage systems within years were not significant for either crop, but profit for no-tillage and strip-tillage corn was the highest in four of five years. The five-year average profit for soybean was also highest for the no-tillage, narrow-row system. Rotating corn and soybean using no-tillage systems resulted in $130 to $145 ha−1 ($53 to $59 ac−1) more profit than the other practices. Farmers, crop consultants, and others should carefully consider overall profit rather than just crop yieid when evaluating alternative tillage practices.

Abstract: Forestlands disturbed by wildfire commonly constitute major and long-lasting sources of sediment that degrade water quality and cause siltation. Postfire restoration of the resistance to erosion of the forest soil is largely controlled by the rate of regrowth of vegetation and may take several years to return to prefire levels, particularly in areas of high-severity burns in semiarid climate. Time-instantaneous prediction techniques such as the Universal Soil Loss Equation (USLE) fail to describe the long-term effect. The latest version of the Revised Universal Soil Loss Equation (RUSLE version 2.0) includes a time-varying option that can model seasonal or pluri-year variations in biomass and other factors; also, it has revised governing equations and an updated database. RUSLE 2.0 claims to be land-use independent and, thus, it should apply to burned-forest lands with proper input for forest vegetation. This paper discusses this matter and concludes there still exist in RUSLE 2.0 built-in routines and parameters inherited from its agricultural application that hinder its use on burned-forest soils. Moreover, many forest lands are characterized by soil textures and slope gradients that fall near, or outside, the limit of the database used for validating USLE/RUSLE, a condition that may counter RUSLE9s overall improvement in precision and accuracy.

Abstract: Agricultural nonpoint source pollution (NPS) is a major water quality concern throughout the United States and the world. Concerns over agricultural nonpoint source pollution are heightened where intensive agricultural operations exist near environmentally sensitive waters. To address these environmental concerns, a water quality demonstration project involving federal, state, and local agencies, private industry, and local landowners was initiated in 1990 on the Herrings Marsh Run watershed in the Cape Fear River Basin in Duplin County, North Carolina. Best management practices (BMPs) to reduce nutrient losses to the environment included nutrient and animal waste management plans, soil conservation practices, and an in-stream wetland (ISW). Stream nitrate-N and ammonia-N were measured at the watershed outlet and at three subwatershed outlets from 1990-1998 to evaluate the effectiveness of the best management practices. The project was divided into pre-in-stream wetland (September 1990-May 1993) and post-in-stream wetland (June 1993-December 1998) time periods because the majority of the best management practices were implemented at the time of the in-stream wetland establishment. Post- in-stream wetland stream nitrate-N concentrations were significantly reduced on the watershed (56%) and on each of the three subwatersheds (4% to 56%). The watershed nitrate-N concentrations were reduced from 2.01 to 0.88 mg/L (ppm). One subwatershed had stream nitrate-N concentrations reduced from 5.63 to 2.74 mg/L (ppm). Nitrate-N mass export from the watershed was significantly reduced on an annual basis from 7.14 to 3.88 kg/ha (6.37 to 3.46 lb/ac). Ammonia-N concentrations and mass export from the watershed were unchanged from the pre- to post-in-stream wetland periods. The results of this study indicate that the implemented best management practices were effective in reducing nitrogen loss from the Herrings Marsh Run watershed.