scholarly journals Leaching of Escherichia coli O157:H7 in Diverse Soils under Various Agricultural Management Practices

2000 ◽  
Vol 66 (3) ◽  
pp. 877-883 ◽  
Author(s):  
Joel V. Gagliardi ◽  
Jeffrey S. Karns

ABSTRACT Application of animal manures to soil as crop fertilizers is an important means for recycling the nitrogen and phosphorus which the manures contain. Animal manures also contain bacteria, including many types of pathogens. Manure pathogen levels depend on the source animal, the animal's state of health, and how the manure was stored or treated before use. Rainfall may result in pathogen spread into soil by runoff from stored or unincorporated manure or by leaching through the soil profile. Steady rainfall consisting of 16.5 mm h−1 was applied to 100-mm disturbed soil cores that were treated with manure and inoculated with Escherichia coli O157:H7 strain B6914. The level of B6914 in leachate was near the inoculum level each hour for 8 h, as was the level of B6914 at several soil depths after 24 h, indicating that there was a high rate of growth. Bacterial movement through three different types of soil was then compared by using disturbed (tilled) and intact (no-till) soil cores and less intense rainfall consisting of 25.4 mm on 4 consecutive days and then four more times over a 17-day period. Total B6914 levels exceeded the inoculum levels for all treatments except intact clay loam cores. B6914 levels in daily leachate samples decreased sharply with time, although the levels were more constant when intact sandy loam cores were used. The presence of manure often increased total B6914 leachate and soil levels in intact cores but had the opposite effect on disturbed soil cores. Ammonia and nitrate levels correlated with B6914 and total coliform levels in leachate. We concluded that tillage practice, soil type, and method of pathogen delivery affect but do not prevent vertical E. coli O157:H7 and coliform transport in soil and that soluble nitrogen may enhance transport.

1989 ◽  
Vol 69 (3) ◽  
pp. 729-739
Author(s):  
C. A. GRANT

Disturbed soil cores, at two bulk densities, and undisturbed soil cores were collected from two fields which had been maintained under reduced tillage management. Dry matter yield of growth chamber-grown barley in the disturbed soil cores was equal to or lower than that produced in the undisturbed cores but was unaffected by degree of soil compaction. Increase in dry matter yield in response to K or Cl fertilization was greater in disturbed than undisturbed soils. Compaction did not generally influence response to KCl fertilization. Soil disturbance did not consistently influence concentration of N, K or Cl in barley tissue. Tissue content of Zn was increased by soil disturbance in the clay loam soil and decreased by soil disturbance in the sandy loam soil. Compaction did not influence tissue content of N or Cl. Compaction did not influence K content of plants grown on the clay loam soil, which initially had high levels of plant-available K, but reduced K content of plants grown on K-deficient sandy loam soil. Increased compaction also reduced the Zn content of plants in the sandy loam soil but increased Zn content of plants in the clay loam soil. Application of KCl or CaCl2 increased Cl content of barley tissue and tended to reduce the N content of the tissue, particularly in the clay loam soil. Application of KCl or KNO3 increased K concentration in barley tissue grown on the K-deficient sandy loam soil but not on the higher K clay loam soil.Key words: Potassium, chloride, zinc, compaction, bulk density, barley


1994 ◽  
Vol 30 (6) ◽  
pp. 31-40 ◽  
Author(s):  
Hiroyshi Emori ◽  
Hiroki Nakamura ◽  
Tatsuo Sumino ◽  
Tadashi Takeshima ◽  
Katsuzo Motegi ◽  
...  

For the sewage treatment plants near rivers and closed water bodies in urbanized areas in Japan and European countries, there is a growing demand for introduction of advanced treatment processes for nitrogen and phosphorus from the viewpoints of water quality conservation and environmental protection. In order to remove nitrogen by the conventional biological treatment techniques, it is necessary to make a substantial expansion of the facility as compared with the conventional activated sludge process. In such urbanized districts, it is difficult to secure a site and much capital is required to expand the existing treatment plant. To solve these problems, a compact single sludge pre-denitrification process using immobilized nitrifiers was developed. Dosing the pellets, which are suitable for nitrifiers growth and physically durable, into the nitrification tank of single sludge pre-denitrification process made it possible to perform simultaneous removal of BOD and nitrogen in a retention time equal to that in the conventional activated sludge process even at the low water temperature of about 10 °C. The 3,000 m3/d full-scale conventional activated sludge plant was retrofitted and has been successfully operated.


1993 ◽  
Vol 28 (3-5) ◽  
pp. 691-700 ◽  
Author(s):  
J. P. Craig ◽  
R. R. Weil

In December, 1987, the states in the Chesapeake Bay region, along with the federal government, signed an agreement which called for a 40% reduction in nitrogen and phosphorus loadings to the Bay by the year 2000. To accomplish this goal, major reductions in nutrient loadings associated with agricultural management practices were deemed necessary. The objective of this study was to determine if reducing fertilizer inputs to the NT system would result in a reduction in nitrogen contamination of groundwater. In this study, groundwater, soil, and percolate samples were collected from two cropping systems. The first system was a conventional no-till (NT) grain production system with a two-year rotation of corn/winter wheat/double crop soybean. The second system, denoted low-input sustainable agriculture (LISA), produced the same crops using a winter legume and relay-cropped soybeans into standing wheat to reduce nitrogen and herbicide inputs. Nitrate-nitrogen concentrations in groundwater were significantly lower under the LISA system. Over 80% of the NT groundwater samples had NO3-N concentrations greater than 10 mgl-1, compared to only 4% for the LISA cropping system. Significantly lower soil mineral N to a depth of 180 cm was also observed. The NT soil had nearly twice as much mineral N present in the 90-180 cm portion than the LISA cropping system.


Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 545
Author(s):  
Paramanandham Krishnamoorthy ◽  
Kuralayanapalya P. Suresh ◽  
Kavitha S. Jayamma ◽  
Bibek R. Shome ◽  
Sharanagouda S. Patil ◽  
...  

In this study, the major mastitis pathogen prevalence in the cattle and buffalo of the world was estimated by a meta-analysis. Staphylococcus (S) species, Streptococcus (St) species, and Escherichia coli (Ec) prevalence studies reported during 1979–2019 were collected using online databases, and offline resources. A meta-analysis of these data was done with the meta package in R-Software. The Staphylococcus aureus was the major mastitis pathogen, mostly causing subclinical mastitis, Ec causing clinical mastitis and St causing subclinical and clinical mastitis. The pooled prevalence estimates of S, St, and Ec were 28%, 12%, and 11% in the world from 156, 129, and 92 studies, respectively. The S, St, and Ec prevalences were high in Latin America (51%), Oceania (25%), and Oceania (28%), respectively. Higher S, St, and Ec prevalences were observed by molecular methods, signifying high sensitivity and usefulness for future studies. Among bacterial species, S. aureus (25%) followed by coagulase-negative Staphylococcus species (20%), Escherichia coli (11%), St. agalactiae (9%), St. uberis (9%) were the important pathogens present in the milk of the world. We hypothesize that there is a urgent need to reduce mastitis pathogen prevalence by ensuring scientific farm management practices, proper feeding, therapeutic interventions to augment profits in dairying, and improving animal and human health.


Carbon ◽  
2021 ◽  
Author(s):  
Xiaoqing Ma ◽  
Nan Xiao ◽  
Jian Xiao ◽  
Xuedan Song ◽  
Hongda Guo ◽  
...  

2015 ◽  
Vol 4 (3) ◽  
pp. 116 ◽  
Author(s):  
Lynette K. Abbott ◽  
David A. C. Manning

<p>Soil health is dependent upon complex bio-physical and bio-chemical processes which interact in space and time. Microrganisms and fauna in soil comprise highly diverse and dynamic communities that contribute, over either short or long time frames, to the transformation of geological minerals and release of essential nutrients for plant growth. Certified organic soil management practices generally restrict the use of chemically-processed highly soluble plant nutrients, leading to dependence on nutrient sources that require microbial transformation of poorly soluble geological minerals. Consequently, slow release of nutrients controls their rate of uptake by plants and associated plant physiological processes. Microbial and faunal interactions influence soil structure at various scales, within and between crystalline mineral grains, creating complex soil pore networks that further influence soil function, including the nutrient release and uptake by roots. The incorporation of organic matter into soil, as either manure or compost in organic farming systems is controlled to avoid excessive release of soluble nutrients such as nitrogen and phosphorus, while simultaneously contributing an essential source of carbon for growth and activity of soil organisms. The interdependence of many soil physical and chemical processes contributing to soil health is strongly linked to activities of the organisms living in soil as well as to root structure and function. Capitalizing on these contributions to soil health cannot be achieved without holistic, multiscale approaches to nutrient management, an understanding of interactions between carbon pools, mineral complexes and soil mineralogy, and detailed examination of farm nutrient budgets.</p>


1992 ◽  
Vol 25 (12) ◽  
pp. 207-214 ◽  
Author(s):  
N. J. Cromar ◽  
N. J. Martin ◽  
N. Christofi ◽  
P. A. Read ◽  
H. J. Fallowfield

Two High-Rate Algal Ponds were operated over residence times of 4 and 6 days respectively, at three COD loading rates equivalent to 600, 350 and 100 kg ha−1d−1 from early September to late October 1991. Samples of pond N and P feed were analysed to obtain nutrient input values to the system. Pond filtrates were also analysed for soluble nutrients. The pond biomass was separated into constituent components of algae and bacteria. Following separation, the discrete fractions were analysed for dry matter, chlorophyll content, and paniculate carbon, hydrogen, nitrogen and phosphorus. Nitrogen and phosphorus balances were then calculated which were used to partition the nutrients into soluble and paniculate phases, and to further separate the paniculate phase into algal and bacterial components. The partitioning of these nutrients, responsible for eutrophication, enables the calculation of removal rates of N and P from the pond systems and makes possible more effective strategies for the removal of the nutrient-rich biomass from receiving water bodies.


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