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1.
No-till (NT) farming (conservation agriculture) began in the US in the 1960s. The state of Ohio has a university research location that began no-till research in 1962. A few innovative Ohio farmers, including NT pioneers David Brandt and Bill Richards, were early adopters of the new conservation practice. Initially, no-till was most successful on sloping, well drained soils, then with improvements to the system, including cover crops, it became more widely adopted on all soil types. David Brandt was an enthusiastic learner and teacher of no-till practices, working with chemical company representatives and Cooperative Extension Specialists to demonstrate the system.David Brandt's cooperation with Ohio State University researchers continues to provide a valuable site for studying the long term changes in soil health and ecosystem services. Results showed that total microbial biomass as one of the soil biological health indicators significantly increased with an associated decrease in carbon (C) loss under NT compared with conventional tilled soil (CT). Under NT, there was significantly higher total C and total N compared to CT. Active C, as a composite measure of soil health, significantly increased with NT. When cover crops, especially cover crop cocktail mixes, were used, NT substantially improved soil health. Long-term NT with cover crop cocktail mixes significantly increased the soil aggregate stability, compared with CT. The overall rate of C sequestration by NT suggested that the soils on the Brandt farm act as a consistent sink of atmospheric CO2 although this tends to level off after about 20 years. The Brandt farm showed that crop yields are increased under long-term NT with cover crops mixes. Results suggested that starting with a cover crop when switching from CT to NT, is more likely to ensure success and to maintain economic crop yields.Another early adopter, Bill Richards, from Circleville, Ohio, also became a national leader and promoter of no-till farming. He served as head of the United States Department of Agriculture's Natural Resources Conservation Service in the early 1990s and instituted a program that led to rapid expansion of no-till. He advises that farmers who follow conservation agriculture principles need to be more proactive, from local level to national levels, to influence policy decisions that can lead to robust improvement in soil health.  相似文献   

2.
In the United States, more farms are composting than municipalities, commercial/institutional establishments, and other private sector groups combined. To obtain an overview of agricultural composting in the United States, industry, government, and university representatives from the top 10 beef and dairy cattle, poultry, and swine producing states were contacted between January and April of 1995. These states represent at least 70 percent of the nation's production of these commodities (except for beef cattle at 52 percent). The representatives provided information about the number of farms composting, the materials composted, composting methods, how the compost is used, and motivating and impeding factors for farms to compost. In addition, information was gathered concerning composting crop residues. In this case, specific applications of crop residue composting were identified and individuals knowledgeable about the applications were contacted for background information.

Note the estimated numbers of composting operations presented here represent a best attempt to quantify the composting activity taking place on various types of farms. In many cases, the numbers are rough estimates, based on the assessments of the representatives contacted in each state. Also, they only include the composting operations in the top 10 producing states. A considerable amount of composting occurs outside of these states. Therefore, Tables 1 and 2 underestimate the number of farms that compost.  相似文献   

3.
The need to conserve United States populations of Lepidoptera has been recognised for a century, but intensive programmes to do so have only recently come into being. The evolution of the butterfly and moth conservation movement in the United States is followed from the earliest instances to the present state of progress. The origin and growth of the Xerces Society as the chief body for terrestrial arthropod conservation in America are described. Currently, ecological research and political action aimed at specific lepidopteran protection issues are under way. Several of these are examined and the most acute needs for further study and action indicated. Habitat alteration emerges dramatically as the chief problem in the decline of butterfly and moth populations. The relative importance of pesticides and overcollecting is discussed and reinforces the conclusion that the habitat is paramount. Introductions of organisms for purposes of conservation likewise receive consideration, showing this strategy to be problematical and subject to careful review prior to its use. The various levels of government as well as private bodies and individuals have distinct roles in insect conservation. Greater public awareness of beneficial insects must precede optimal effectiveness of conservation schemes. The appointment of an official federal insect conservator is announced along with his initial proposal for endangered species listings for certain North American butterflies. The prognosis for a national programme is suggested. Lepidoptera conservation in the United States has become a fully fledged movement with numerous successes and with many difficult problems to face. The situation is viewed with immediate alarm but cautious long-term optimism as well.  相似文献   

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5.
Conservation benefits of conservation tillage had been developed long before the production disadvantages were removed. Even though, in some cases, there are still production disadvantages and lower yields, compared to conventional tillage, conservation tillage is attractive to farmers primarily because of the potential for reduced production costs; conservation benefits are of secondary interest in most cases even though they accrue from the use of conservation tillage. This farmer interest in cost reduction will most certainly guide research inputs. Surveys of farmers have shown that more emphasis must be placed on all of the technology needed for a production system. In order to avoid financially-disastrous consequences, associated risk assessments are even required during the adoption period, i.e., the period when conservation tillage is replacing the conventional tillage.When a conservation-tillage-planting system is defined rigorously, based on the requirement that at least 30% of the surface should be covered with crop residue, the adoption averages about 25% of the cropland in the United States. Nine tillage management regions (TMR) in the United States were delineated based on climate, adapted crops and cropping systems. Adoption of conservation-tillage-planting systems ranged widely from 22 to 45% of the cropland in a TMR. Full-width systems such as mulch till, in which the whole field is tilled, were used much more than partial-width systems such as no-till, ridge till and strip till in which only strips are tilled. Adoption of these forms of conservation tillage are sensitive to the dominant-cropping systems in a TMR. Variations in adoption were often well related to the problems and benefits discussed by research on tillage-planting systems in the TMR.  相似文献   

6.
The average deposition rate of sea salt chloride over the world continents is about 10 meq m?2 yr?1. Only about 14 ± 1% of chloride in the pollution-corrected world average river is contributed by seasalt aerosols and the rest from the dissolution of evaporites. The significant increase of the ion concentrations in the Mississippi river from the year 1905 to 1987 was caused by anthropogenic inputs such as fossil fuel burning, common salt consumption, and dissolution of carbonate and silicate rocks by acids derived from acid precipitation.  相似文献   

7.
Acid rain has become a major environmental concern, the current extent of which is illustrated in this paper. Maps of both pH and H+ deposition in precipitation have been developed for the continental United States by analyzing laboratory pH data from nine precipitation chemistry networks and two single stations spread across the continental United States and southern Canada during the late 1970's. Average laboratory pH values were obtained or calculated for approximately 100 stations, and isopleths of weighted mean pH and mean annual H+ deposition in precipitation were drawn. Results of this analysis show that in spite of a wide variety of collection methods and sampling intervals, there is remarkable uniformity in the average pH among the various stations. The northeastern United States continues to exhibit the most acidic precipitation, with remaining portions of the eastern United States, states along the western coastline and a pocket in central Colorado also experiencing acid precipitation.  相似文献   

8.
Mercury (Hg) contamination from a variety of point and non-point sources, including atmospheric inputs, is currently considered to be the most serious environmental threat to the well being of fish and wildlife resources in the southeastern United States. Fish consumption advisories have been issued in all ten states comprising the U.S. Fish and Wildlife Service's Southeast Region. Both freshwater and marine species have been affected with levels ranging as high as 7.0 ppm in some individuals. Many other species, including various species of reptiles, birds and mammals (including humans) are also contaminated. Impacts noted range from reproductive impairment to mortality.  相似文献   

9.
Perchlorate has the potential to cause thyroid dysfunction by inhibiting iodide uptake by the sodium iodide symporter. Perchlorate-contaminated waters may lead to human exposure through drinking water and food chain transfer in crops by way of irrigation water. Perchlorate has been found in dairy milk collected nationally and internationally. This study was conducted to evaluate perchlorate in the feed-dairy continuum in the southwestern United States. All feed products collected at dairies in this study had detectable levels of perchlorate as analyzed by ion chromatography-tandem mass spectrometry. The calculated total perchlorate intake across dairies ranged from 1.9 to 12.7 mg/cow per day. The variation in total perchlorate intake across dairies was largely associated with variation in forage and silage products. Alfalfa products were the single most important source of perchlorate intake variability among dairies. The estimated perchlorate intake from drinking water ranged from 0.01 mg per cow per day and was generally less than 2% of the total perchlorate intake. The perchlorate content of milk ranged from 0.9 to 10.3 microg/L and was similar to levels reported by the Food and Drug Administration's Total Diet Study. The perchlorate content of milk was significantly related to the presence of perchlorate in feed but the variation of perchlorate in milk could not be explained by feed intake alone.  相似文献   

10.
J.H. Huddleston 《Geoderma》1984,32(4):297-317
This paper provides historical documentation of major U.S. efforts to develop numerical ratings of soil productivity. Nearly all of these efforts stemmed from needs to compare different soils objectively for purposes of agricultural land use planning and the equalization of land values and tax assessments.Several approaches are described, including U.S.D.A. work following World War I, ratings based solely on crop yield data, Storie's (1933, 1937, 1976) multiplicative factor approaches and the variations that evolved from them, and “Soil property systems” that add, rather than multiply, effects of separate factors. Taken together, these various approaches highlight a large number of soil properties, weather conditions, and crop yield data that need to be considered to develop ratings of soil productivity. They illustrate a variety of techniques for evaluating the effects of soil properties quantitatively and for combining soil factor values into overall soil ratings. Each approach has certain advantages and limitations, and these are discussed throughout. The collective experiences with the development and use of productivity ratings cover a diversity of soil and climatic conditions throughout the United States.  相似文献   

11.
A limited survey was conducted over a 2-year period to determine the incidence and levels of deoxynivalenol (DON) in corn and wheat grown in selected areas of the United States. Samples of corn (198) and wheat (247) were collected and analyzed by a gas chromatographic method. Sixty-six percent of the corn samples collected in 1984 and 30% of the corn samples collected in 1985 contained DON. The average concentration of DON in corn, by state, ranged from 0.11 to 1.20 micrograms/g; the maximum concentration was 2.47 micrograms/g. Only 2 of the 247 samples of wheat contained DON at a concentration greater than 2 micrograms/g, which is the level of concern suggested by the Food and Drug Administration for wheat entering the milling process for human consumption.  相似文献   

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14.
Soil Taxonomy was developed primarily for the practical purpose of supporting the National Cooperative Soil Survey Program in the United States. The previous system of classification was limited in its usefulness and could not be applied consistently by a large cadre of soil scientists with diverse levels of skill and experience. The first edition of Soil Taxonomy, published in 1975, was developed under the leadership of Dr. Guy Smith over a period of about 25 years. The magnitude and complexity of the information favored the use of a hierarchical system presented as a key for consistent application. Operational definitions were used to identify taxonomic limits and diagnostic horizons and features, so that each taxon conveyed the same meaning to every user. The application of Soil Taxonomy had several important impacts on the soil survey program in the United States. The emphasis on objective, measurable diagnostic horizons and features to define classes made all competent soil scientists, regardless of experience and rank, equally capable of accurately and consistently classifying soils. The use of quantitative class differentia improved the quantity and quality of the field data collection. The property ranges of soil series and their geographic distribution have generally been narrowed over time, thus, allowing more precise interpretations to be made. Soil Taxonomy has benefited the soil correlation process by grouping the nearly 22 000 series currently established in the United States in ways that allow us to efficiently compare and differentiate competing soil series and coordinates their use among survey areas. After publication in 1975, Soil Taxonomy was further refined through the work of nine international committees and many individuals. This work culminated in the publication of the second edition in 1999 and, most recently, the 9th edition of the Keys to Soil Taxonomy in 2003. Today, two international committees are considering revisions to the moisture and temperature regimes and improvements to the classification of anthropogenic soils. Published in Russian in Pochvovedenie, 2006, No. 2, pp. 161–167. This article was submitted by the authors in English.  相似文献   

15.
Land-based recycling of processed sewage sludge (biosolids) has traditionally been challenged by concerns over metals, organics, pathogens, odors, and public perception. Nutrient concerns, however, portend even greater challenges, and threaten land application programs in the US. Long-term application of biosolids results in accumulation of soil phosphorus (P) above concentrations needed for optimum crop yields. Water quality impairment associated with accelerated eutrophication is driving the US states to adopt policies and laws to reduce P losses to surface waters from agricultural land. Nearly all states have developed site assessment tools (P indices) to rank fields based on their vulnerability to P loss and to target remedial strategies. Biosolids have not been systematically addressed in most states and sustaining economical biosolids recycling programs will be difficult if policies fail to consider certain critical issues. Soil test P benchmarks should be based upon environmental P loss risk rather than crop response. Policies must recognize the role of mandated buffers in protecting surface water quality. Site indices must account for the sizable differences in P loss potential among biosolids types compared to mineral fertilizers and livestock manures. Finally, agronomic rate calculations must recognize different P fertilizer replacement values among biosolids products. Deployment of P management regulations for biosolids lacking scientifically defensible strategies in these areas will adversely affect land-based recycling. Sustainability requires additional research and intentional inclusion of biosolids in implementation of evolving P management policies.  相似文献   

16.
Conservation tillage was used on nearly 36% of planted hectares in 1996 in the U.S. This level has remained relatively unchanged since 1991. The use of conservation tillage varies by crop and is dependent on site-specific factors including soil sype, topsoil depth, and local climate conditions. A number of economic, demographic, geographic, and policy factors have affected the adsorption of conservation tillage. While it is not possible to quantify exactly the impact of these factors, it is clear that management complexities and profitability are key factors impeding the further adsorption of conservation tillage.  相似文献   

17.
Abstract

A survey was conducted of 55 state and 371 commercial laboratories throughout the United States in order to document the current applications of plant analyses and the extent of application of the diagnosis and recommendation integrated system (DRIS) and to identify factors that have hindered or facilitated the implementation of the DRIS. State labs listed “research”; and commercial labs listed “diagnosis of nutrient deficiencies”; as the most common uses for plant analyses. Plant analysis results were widely used in combination with soil tests when diagnosing nutrient deficiencies and recommending corrective action (96% of state labs and 92% of commercial labs diagnosing nutrient deficiencies). Nationwide, the sufficiency range was the most commonly identified method of interpreting plant analyses (61% of the state and 58% of the commercial labs). The DRIS was used more extensively in the North Central region (14 labs) than in any other region. The two most commonly identified factors hindering the implementation of the DRIS were 1) lack of field verification and/or calibration and correlation data and, 2) unfamiliarity with the system. Computer availability appears to be the most important factor facilitating the implementation of the DRIS.  相似文献   

18.
Phytosterols were quantified in nuts and seeds commonly consumed in the United States. Total lipid extracts were subjected to acid hydrolysis and then alkaline saponfication, and free sterols were analyzed as trimethylsilyl derivatives by capillary GC-FID and GC-MS. Delta5-Avenasterol was quantified after alkaline saponification plus direct analysis of the glucoside. Sesame seed and wheat germ had the highest total phytosterol content (400-413 mg/100 g) and Brazil nuts the lowest (95 mg/100 g). Of the products typically consumed as snack foods, pistachio and sunflower kernel were richest in phytosterols (270-289 mg/100 g). beta-Sitosterol, Delta5-avenasterol, and campesterol were predominant. Campestanol ranged from 1.0 to 12.7 mg/100 g. Only 13 mg/100 g beta-sitosterol was found in pumpkin seed kernel, although total sterol content was high (265 mg/100 g). Phytosterol concentrations were greater than reported in existing food composition databases, probably due to the inclusion of steryl glycosides, which represent a significant portion of total sterols in nuts and seeds.  相似文献   

19.
Both lipophilic and hydrophilic antioxidant capacities were determined using the oxygen radical absorbance capacity (ORAC(FL)) assay with fluorescein as the fluorescent probe and 2,2'-azobis(2-amidinopropane) dihydrochloride as a peroxyl radical generator on over 100 different kinds of foods, including fruits, vegetables, nuts, dried fruits, spices, cereals, infant, and other foods. Most of the foods were collected from four different regions and during two different seasons in U.S. markets. Total phenolics of each sample were also measured using the Folin-Ciocalteu reagent. Hydrophilic ORAC(FL) values (H-ORAC(FL)) ranged from 0.87 to 2641 micromol of Trolox equivalents (TE)/g among all of the foods, whereas lipophilic ORAC(FL) values (L-ORAC(FL)) ranged from 0.07 to 1611 micromol of TE/g. Generally, L-ORAC(FL) values were <10% of the H-ORAC(FL) values except for a very few samples. Total antioxidant capacity was calculated by combining L-ORAC(FL) and H-ORAC(FL). Differences of ORAC(FL) values in fruits and vegetables from different seasons and regions were relatively large for some foods but could not be analyzed in detail because of the sampling scheme. Two different processing methods, cooking and peeling, were used on selected foods to evaluate the impact of processing on ORAC(FL). The data demonstrated that processing can have significant effects on ORAC(FL). Considering all of the foods analyzed, the relationship between TP and H-ORAC(FL) showed a very weak correlation. Total hydrophilic and lipophilic antioxidant capacity intakes were calculated to be 5558 and 166 micromol of TE/day, respectively, on the basis of data from the USDA Continuing Survey of Food Intakes by Individuals (1994-1996).  相似文献   

20.
In 2004, the Agricultural Safety and Health Centers, supported by the National Institute for Occupational Safety and Health, launched an initiative to conduct research on the consequences of and approaches to control of agricultural tractor-related injuries. The most significant cause of fatal injuries is associated with tractor overturns, and a recognized intervention to control these injuries is equipping the tractor with a rollover protective structure (ROPS). The purpose of this study was to determine the incidence of tractor-related fatal and nonfatal injuries and their social costs. Based upon the annual average incidence of 125 tractor-overturn-related fatalities in the U.S. for the period 1992 to 2002, an analysis was conducted of injuries over the 25-year period 1997 to 2021. Using the number of fatalities as an index value, the analysis found that in 1997, there were a total of 2,412 tractor overturns. These overturns were associated with 125 deaths and 573 nonfatal injuries requiring at least outpatient treatment. Compared to ROPS-equipped tractors, 123 (98.6%) deaths and 543 (95%) of nonfatal injuries were associated with non-ROPS tractor overturns. The undiscounted social cost of these injuries totaled $1.5 billion in 2006 dollars for the 25-year period when using cost factors for the agricultural population. When discounted at 3%, this total was $1.1 billion, and when discounted at 5%, it was $0.9 billion. In an alternative analysis, when using cost factors for all occupations including agriculture, the undiscounted social cost totaled $2.9 billion, $2.1 billion when discounted at 3%, and $1.7 billion discounted at 5% for the 25-year period. Non-ROPS tractors as compared to ROPS-equipped tractors account for at least 97% of the costs, no matter the discount rate or cost factors used.  相似文献   

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