THE ESTIMATED NUMBER OF NEMAS IN THE SOILS OF MANITOBA

1934 ◽  
Vol 11 (5) ◽  
pp. 594-601
Author(s):  
E. H. J. Marchant
Keyword(s):  
United States ◽  
Organic Matter ◽  
Organic Matter Content ◽  
The United States ◽  
Matter Content ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Number Of Species ◽  
Moisture Equivalent

Samples of soil, taken from 29 different sections of the arable portions of Manitoba, have been analyzed. Twelve species of eight genera of nematodes have been identified. No species of the genus Heterodera were found.An endeavor has been made, first, to determine the approximate degree of infestation, and second, to correlate such factors as hydrogen ion concentration, moisture equivalent, and organic matter content with the nema counts.The nematode population is somewhat higher in the soils of Manitoba than in those of many parts of the United States, but considerably lower than in those of North China.The number of species seems to be limited.The degree of infestation appears to be negatively affected by either hydrogen ion concentration or moisture equivalent, but is decidedly influenced by organic matter content.

Dissipation of Herbicides at Three Soil Depths

Weed Science ◽  
1969 ◽  
Vol 17 (1) ◽  
pp. 27-31 ◽  
Author(s):  
C. I. Harris ◽  
E. A. Woolson ◽  
B. E. Hummer
Keyword(s):  
United States ◽  
Organic Matter ◽  
Puerto Rico ◽  
Soil Organic Matter ◽  
Organic Matter Content ◽  
The United States ◽  
Vertical Movement ◽  
Matter Content ◽  
Soil Organic Matter Content ◽  
Positive Correlation

Twelve locations in the United States and Puerto Rico were the sites for determining the loss of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) and 2,3,6-trichlorophenylacetic acid (fenac) from soil. The herbicides were contained in tubes (1.88 by 6 inches) placed at depths of 3, 9, and 15 inches in the field. The samples were placed horizontally to minimize losses due to vertical movement of water from the tubes. After at least 3 months in the soil, the samples were returned to Beltsville and analyzed. Average recoveries showed 61% more atrazine and 41% more fenac from the 15-inch depth than from the 3-inch depth. Five northern samples contained more than twice as much atrazine and fenac residue as four southern samples. A positive correlation existed between fenac retention and soil organic matter content. Increasing soil organic matter and depth of placement, and decreasing temperature, tended to make the herbicides more persistent. However, the data were quite variable and the variations were often unexplainable.

Soil Properties Influence Saflufenacil Phytotoxicity

Weed Science ◽  
2014 ◽  
Vol 62 (4) ◽  
pp. 657-663 ◽  
Author(s):  
Travis W. Gannon ◽  
Adam C. Hixson ◽  
Kyle E. Keller ◽  
Jerome B. Weber ◽  
Stevan Z. Knezevic ◽  
...  
Keyword(s):  
Organic Matter ◽  
Regression Analysis ◽  
Soil Properties ◽  
Texture Classification ◽  
Organic Matter Content ◽  
The United States ◽  
Exchange Capacity ◽  
Matter Content ◽  
Crop Tolerance ◽  
Wide Range

Saflufenacil, a pyrimidinedione herbicide, is used for contact and residual broadleaf weed control in various crops. Bioactivity of saflufenacil in soil was tested in greenhouse and laboratory studies on 29 soils representing a wide range of soil properties and geographic areas across the United States. A greenhouse bioassay method was developed using various concentrations of saflufenacil applied PPI to each soil. Whole canola plants were harvested 14 d after treatment, and fresh and dry weights were recorded. Nonlinear regression analysis was used to determine the effective saflufenacil doses for 50% (ED50,), 80% (ED80), and 90% (ED90) inhibition of total plant fresh weight. Bioactivity of saflufenacil in soil was strongly correlated to soil organic (R= 0.85) and humic matter (R= 0.81), and less correlated to cation exchange capacity (R= 0.49) and sand content (R= −0.32). Stepwise regression analysis indicated that organic matter was the major soil constituent controlling bioactivity in soil and could be used to predict the bioactivity of saflufenacil. Saflufenacil phytotoxicity was found to be dependent on soil property; therefore, efficacy and crop tolerance from PRE and PPI applications may vary based on soil organic matter content and texture classification.

Use of GAC after enhanced coagulation for the removal of natural organic matter from water for purification

2009 ◽  
Vol 9 (2) ◽  
pp. 173-180 ◽  
Author(s):  
I. García ◽  
L. Moreno
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Environmental Protection Agency ◽  
Organic Matter Content ◽  
The United States ◽  
Matter Content ◽  
Protection Agency ◽  
Enhanced Coagulation ◽  
Water Plant ◽  
Anionic Charge

Filtration with granular activated carbon (GAC) after an enhanced coagulation (EC) process was evaluated in order to determine the effectiveness of GAC in the reduction of natural organic matter (NOM), which should result in much lower formation of trihalomethane in the disinfection step. The results show that a combination of EC and GAC considerably reduces the organic matter content, which is mainly fulvic acid. This type of organic matter is removed with high coagulant dosages which neutralize their high anionic charge. A further reduction of NOM is achieved due the adsorption of NOM by GAC. As a result, the average trihalomethane (THM) concentration was only 14.5±5 μg L−1. Enhanced coagulation alone decreased the NOM concentration by 50%, but the remaining NOM reacted in the chlorination step and a higher average THM concentration was found (38±23 μg L−1). An average THM concentration of 73.8±41.2 μg L−1 was found at the drinking water plant of Boaco when conventional treatment was used. This THM concentration sometimes exceeds the maximum contaminant level of 80 μg L−1 established by the United States Environmental Protection Agency (USEPA), but not the Nicaraguan threshold of 460 μg L−1.

scholarly journals Preliminary Observations on the Relative Importance of the various Factors Responsible for the Death of Fishes in Polluted Waters

1927 ◽  
Vol 14 (3) ◽  
pp. 729-739 ◽  
Author(s):  
Hem Singh Pruthi
Keyword(s):  
Organic Matter ◽  
Oxygen Content ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Relative Importance ◽  
Present Communication ◽  
Straightforward Manner ◽  
Hydrogen Ion Concentration ◽  
The Subject ◽  
Polluted Waters

With the growth of modern, industry the problem of the influence of polluted waters on the bionomics of fishes is becoming very important. Fortunately, biologists anticipated this and many works on the subject have appeared, especially during the last twenty-five years. The polluting substances can be divided into two main classes, namely, (i) those that are directly poisonous to organisms, e.g. gas liquor, sulphites, oils, etc., and (ii) those that give rise to poisonous substances or otherwise make the water undesirable after putrefying, e.g. organic matter in solution and the decomposing bodies of plants and animals. The substances in the first category act in a relatively straightforward manner, and numerous investigators have studied them from several aspects (Shelford, '17; Matthews, '04; Powers, Wells, '15, etc.); it is with regard to those in the second class that many questions are yet unsettled and the present communication deals. We roughly know that the effect of the putrefying substances is to increase the hydrogen ion concentration and decrease the oxygen content of water. It has also been suggested that the byproducts of putrefaction themselves may be poisonous to animals.

scholarly journals THE MICRO-ORGANISMS IN PROFILES OF CERTAIN VIRGIN SOILS IN MANITOBA

1935 ◽  
Vol 13c (1) ◽  
pp. 32-46 ◽  
Author(s):  
M. I. Timonin
Keyword(s):  
Organic Matter ◽  
Anaerobic Bacteria ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Soil Organisms ◽  
Peat Soils ◽  
Hydrogen Ion Concentration ◽  
Bacteria And Fungi ◽  
Micro Organisms ◽  
Number Of Bacteria

Twelve profiles of five different kinds of virgin soils of Manitoba were sampled, described and critically examined for soil organisms, hydrogen ion concentration and the moisture and organic matter present. Usually the A horizon showed the highest count of each group of micro-organisms and the C horizon the lowest although the greatest number of bacteria were present in the B horizon of boil 1 in the month of May. The proportion of anaerobic bacteria and fungi to total numbers increased with the depth of the horizon. Moisture content of the soil was not found to exert any consistent effect upon the numbers of micro-organisms present. Fungi were most abundant in the wooded and peat soils, bacteria more so in soils of the meadow-prairie phase. In the wooded soils the microbiological horizons appeared to coincide with the morphological horizons.

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