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Nitrification In Acid Soils, R. E. Stepheson 2017 Iowa State College

Nitrification In Acid Soils, R. E. Stepheson

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

It is quite generally believed now that nitrification may occur in acid soils, at least to some extent. The addition of lime, however, results in practically all cases in an increased activity of the nitrifying flora. This is especially true when soils are strongly acid in reaction and low in organic matter and when ammonium sulfate is used to measure nitrification.

Probably it is not merely because lime neutralizes acid soil conditions that it increases nitrification. There may be very important indirect effects of liming which are responsible for greater nitrifying action. Lime makes the soil conditions more favorable for ...


Effect Of Seasonal Conditions And Soil Treatment On Bacteria And Molds In Soil, P. E. Brown, W. V. Halversen 2017 Iowa State College

Effect Of Seasonal Conditions And Soil Treatment On Bacteria And Molds In Soil, P. E. Brown, W. V. Halversen

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

The study of the microorganic population of the soil has revealed many interesting facts but none more significant nor of more far-reaching importance than the discovery that molds occur in soils and perform various functions which directly or indirectly exert considerable influence on soil fertility.

The occurrence and activities of bacteria in the soil has been the subject of extensive inquiry and much knowledge along this line has been accumulated. These organisms have been found to occur in large numbers in practically all soils and to play a prominent part in the reactions which must necessarily take place in soils ...


Effects Of Certain Alkali Salts On Ammonification, P. E. Brown, D. R. Johnson 2017 Iowa State College

Effects Of Certain Alkali Salts On Ammonification, P. E. Brown, D. R. Johnson

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

The occurrence of so-called" alkali spots" in certain Iowa soils has been nnted in recent publications, these spots are found only in the Wisconsin drift soil area, in association with peat deposits, and are the result of course of peculiarly poor drainage conditions. It is unnecessary here to consider further the causes of these formations or the methods which should be followed in reclaiming the areas affected as these points have been discussed in the publications referred to. It will be sufficient to call attention to the results of the chemical studies of the spots and to consider briefly some ...


Phosphorus, Potassium And Ph Management Issues Following Drought-Damaged Crops, Antonio P. Mallarino, John E. Sawyer 2017 Iowa State University

Phosphorus, Potassium And Ph Management Issues Following Drought-Damaged Crops, Antonio P. Mallarino, John E. Sawyer

John E. Sawyer

Exceptionally dry conditions this summer will result in low crop yield in much of Iowa, and weather forecasts call for normal or below normal rainfall through the fall. These dry conditions and low yields will significantly reduce phosphorus (P) and potassium (K) removal with crop harvest, and may also affect soil test P, K and pH results, complicating test interpretations.


Nitrogen Loss—Spring 2013, John E. Sawyer 2017 Iowa State University

Nitrogen Loss—Spring 2013, John E. Sawyer

John E. Sawyer

Dry soils across Iowa from deficit precipitation following the drought in 2012 have changed to excess wetness this spring. Unfortunately, precipitation to replenish subsoil moisture has been much more than needed. As I wrote in an ICM News article earlier this spring, one downside to the excess precipitation has been movement of carryover nitrate deeper into the profile and to tile lines, resulting in high nitrate-N concentrations in surface waters. This means there is less nitrate-N carryover to be utilized by 2013 crops, although as noted in the previous article, not all of the carryover N moved below the three-foot ...


Effect Of Sulfur And Manure On Availability Of Rock Phosphate In Soil, P. E. Brown, A. R. Gwinn 2017 Iowa State College

Effect Of Sulfur And Manure On Availability Of Rock Phosphate In Soil, P. E. Brown, A. R. Gwinn

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

The use of phosphorus fertilizers is now a recognized necessity in all systems of permanent agriculture. However well supplied naturally, all soils gradually become depleted in phosphorous thru the removal of crops and this element must be returned if crop production is to continue satisfactory. Many soils, especially those under long continued cultivation, have been found to respond very profitably to phosphorus fertilization while even the newer, more fertile soils are approaching a condition where phosphorus will soon become the controlling factor of growth. The interest in phosphorus fertilizers is therefore becoming more widespread and the use of these materials ...


Carbon Dioxide Production In Soils And Carbon And Nitrogen Changes In Soils Variously Treated, R. S. Potter, R. S. Snyder 2017 Iowa State College

Carbon Dioxide Production In Soils And Carbon And Nitrogen Changes In Soils Variously Treated, R. S. Potter, R. S. Snyder

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

The carbon dioxide of the soil atmosphere, along with the water, has long been recognized as the most active agent in the decomposition of comparatively inert minerals to give available and soluble plant food material. It is probable that herein lies the great benefit which comes from the application to soil of organic material which not only increases the energy material easily available for the bacteria, but also improves the physical condition of the soil. This in turn increases bacterial activity, which gives rise to increased carbon dioxide production.

At the Iowa Agricultural Experiment Station, for some time past, both ...


Influence Of Humus Forming Materials Of Different Nitrogen-Carbon Ratios On Bacterial Activities, P. E. Brown, F. E. Allison 2017 Iowa State College

Influence Of Humus Forming Materials Of Different Nitrogen-Carbon Ratios On Bacterial Activities, P. E. Brown, F. E. Allison

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

The determination of the nitrogen-carbon ratio in soils is now considered of much importance in fertility studies. Not only does it show the organic matter content of soils more accurately than the more or less arbitrary humus determinations, concerning which considerable difference of opinion exists, but it also throws some light on the rate at which decomposition processes are occurring.


The Effect Of Some Manganese Salts On Ammonification And Nitrification, P. E. Brown, G. A. Minges 2017 Iowa State College

The Effect Of Some Manganese Salts On Ammonification And Nitrification, P. E. Brown, G. A. Minges

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Manganese occurs in practically all soils, but the quantities present are exceedingly variable. Twenty-six typical soils analyzed by Robinson showed the presence of manganese in amounts varying from 0.01 to 0.51 per cent of MnO. Other studies have shown the occurrence of very large amounts in certain soils, but the average of 0.071 per cent MnO given in the work referred to above probably represents fairly accurately the manganese content of normal soils in this country.


Studies In Sulfofication, P. E. Brown, H. W. Johnson 2017 Iowa State College

Studies In Sulfofication, P. E. Brown, H. W. Johnson

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Recent experiments have shown that sulfofication or sulfuroxidation is an important process occurring in field soils. Plants have been found to require considerable amounts of sulfates for their best growth and inasmuch as sulfur is not present in soils in that form, but as unassimilable organic and inorganic compounds, the sulfur-feeding of crops will depend very largely upon the ability of a soil on which they grow to produce sulfates from these unavailable substances. In other words, the total sulfur content of a soil, alone, will not show the sulfur available for plant growth. The sulfofying power of the soil ...


Bacterial Activities And Crop Production, Percy Edgar Brown 2017 Iowa State College

Bacterial Activities And Crop Production, Percy Edgar Brown

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Until the present time studies in soil bacteriology have dealt almost exclusively with the occurrence and activities of microorganisms in the soil and no attempt has been made to interpret experimental results from the standpoint of crop production. This is due, of course, to the fact that as a science soil bacteriology is scarcely out of its infancy and the preliminary investigations in any science must of necessity deal mainly with underlying principles and such studies are always apt to be rather fragmentary in character.


Determination Of Amino Acids And Nitrates In Soils: Amino Acids, Ammonia And Nitrates In Manured And Limed Soil, R. S. Potter, R. S. Snyder 2017 Iowa State College

Determination Of Amino Acids And Nitrates In Soils: Amino Acids, Ammonia And Nitrates In Manured And Limed Soil, R. S. Potter, R. S. Snyder

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

In view of the fact that no data had ever been obtained on the quantitative relationships of the organic material in the soil by such methods as would preclude a chemical transformation, two things seemed desirable, in continuing the humus investigations at the Iowa Agricultural Experiment Station. First, to attempt the analysis of the organic material of the soil without subjecting it to hydrolysis or other chemical change, and second, to correlate the proportionate quantities of the compounds or classes of compounds found with the kind of soil, its history, treatment, fertility, etc.


Sulfofication In Soils, P. E. Brown, E. H. Kellogg 2017 Iowa State College

Sulfofication In Soils, P. E. Brown, E. H. Kellogg

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Sulfur has long been known to be one of the essential plant food constituents. It has always been believed, however, that there was sufficient present in all soils for the optimum growth of crops. This assumption has been very largely based on Wolff's analyses of the ashes of various crops which showed the presence of very small amounts of sulfur.

The recent work of many investigators has demonstrated, however, that the amount of sulfur in plant materials as determined in the ash is, in most cases, entirely too low; that there is a considerable loss of sulfur in the ...


Bacteriological Studies Of Field Soils, Iii. The Effects Of Barnyard Manure, Percy Edgar Brown 2017 Iowa State College

Bacteriological Studies Of Field Soils, Iii. The Effects Of Barnyard Manure, Percy Edgar Brown

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

The conclusions which may be drawn from the experiments upon the effects of barnyard manure on bacteriological activities of field S'oils presented in this bulletin are as follows:

1. Applications of manure up to sixteen tons per acre increased the numbers of organisms in the soil as shown by the growth on modified synthetic and albumen agar. The ammonifying power of the soil as shown by tests with the casein-fresh soil, albumen-fresh soil, dried blood-fresh soil, and dried blood-air-dried soil methods, and the nitrifying power tested by the ammonium sulfate-fresh soil, and the ammonium sulfate-air- dried soil methods were ...


Rapid Surface-Water Volume Estimations In Beaver Ponds, Daniel J. Karran, Cherie J. Westbrook, Joseph M. Wheaton, Carol A. Johnston, Angela Bedard-Haughn 2017 University of Saskatchewan

Rapid Surface-Water Volume Estimations In Beaver Ponds, Daniel J. Karran, Cherie J. Westbrook, Joseph M. Wheaton, Carol A. Johnston, Angela Bedard-Haughn

Watershed Sciences Faculty Publications

Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia, and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface-water storage among the range ...


Methods For The Bacteriological Examination Of Soils, Percy Edgar Brown 2017 Iowa State College

Methods For The Bacteriological Examination Of Soils, Percy Edgar Brown

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

Because the idea of examining soils bacteriologically owed its inception to the development of the gelatine plate method for isolating pure cultures, very naturally the first investigations of soil bacteria were by the use of plate cultures. the studies, therefore, were purely quantitative in nature. The results secured by the pioneers in this work demonstrated some facts of considerable interest, but it soon became evident that mere quantitative determinations of the bacteria in soils were inadequate to give information regarding the relation of such organisms and their activities to the fertility of the soil.


Amino Acids And Acid Amides As Sources Of Ammonia In Soils, S. L. Jodidi 2017 Iowa State College

Amino Acids And Acid Amides As Sources Of Ammonia In Soils, S. L. Jodidi

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

l'he nitrogen recognized as one of the most important elements for plants, if not the most necessary, is being studied and discussed by many investigators ana among them the opinion is quite general that there is a considerable difference between the various forms of nitrogen. this is particularly true of soil nitrogen. Wile in some soils the nitrogen is readily ammonified and furter ifled and further oxidized to nitrites and nitrates, it does not undergo those processes in other soils. In other words, soil nitrogen is available or can easily be made available for plants in some cases, in ...


Bacteria At Different Depths In Some Typical Iowa Soils, Percy Edgar Brown 2017 Iowa State College

Bacteria At Different Depths In Some Typical Iowa Soils, Percy Edgar Brown

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. In the different soil types, as well as in the same soil under different rotations, the greatest number of organisms occurred at a depth of 4 inches.

2. Bacteria were found in considerable numbers at much lower depths in the loess soil than in the drift soil.

3. There was a more or less gradual decrease in numbers to a depth of 3, 5 and in one case of fifteen feet. No sudden increases were observed even where gains in moisture occurred.

4. The greatest decrease in numbers of organisms occurred within the first 12 inches and in some ...


Bacteriological Studies Of Field Soils, Ii. The Effects Of Continuous Cropping And Various Rotations, Percy Edgar Brown 2017 Iowa State College

Bacteriological Studies Of Field Soils, Ii. The Effects Of Continuous Cropping And Various Rotations, Percy Edgar Brown

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

From a bacteriological study of soil plots under both continuous cropping and various crop rotations, these general conclusions were drawn:

1. The rotation of crops caused the development of greater numbers of organisms in the soil and of greater ammonifying, nitrifying, and nitrogen-fixing power by the soil, than continuous cropping either to corn or to clover.

2. Greater numbers of organisms, greater ammonifying, nitrifying, and nitrogen-fixing powers were found in a soil under a three year rotation of corn, oats, and clover, than in a soil under a two year rotation of corn and oats, or in a soil under ...


Bacteriological Studies Of Field Soils, I. The Effects Of Lime, Percy Edgar Brown 2017 Iowa State College

Bacteriological Studies Of Field Soils, I. The Effects Of Lime, Percy Edgar Brown

Research Bulletin (Iowa Agriculture and Home Economics Experiment Station)

1. Applications of limestone up to three tons per acre increased the total number of soil bacteria which develop on "modified synthetic" agar plates.

2. These increases probably occurred in species more resistant to drought.

3. The three ton application gave a proportionately greater increase in numbers than the two tons.

4. Application of limestone up to three tons per acre increased the ammonlfying, the nitrifying, anil the nitrogen fixing powers of the soil.

5. The ammonification of dried blood and cottonseed meal did not run parallel in tests of field soils subjected to continued drought.

6. The three ton ...


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