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Iowa State University

Plant Sciences

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

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Aflatoxin In Corn New Perspectives, D. T. Wicklow Jun 2017

Aflatoxin In Corn New Perspectives, D. T. Wicklow

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Preharvest contamination of com (Zea mays L.) with aflatoxin, a metabolite produced by the fungus Aspergillus flavus Link: Fr., is a recurrent problem in the southeastern United States, but occasional serious outbreaks also occur in the Midwest Com Belt (21). Aflatoxins are recognized as potent hepatotoxins and carcinogens, causing mortality or reducing the productivity of farm animals (89). Aflatoxin-contaminated foodstuffs also have been associated with increased incidence of liver cancer in humans (39). In com-producing regions, the economic impact from yield loss is not very large, but A. flavus contaminates the grain with aflatoxin. Fungal toxins reduce the value of ...


Correlated Responses To Recurrent Selection For Grain Yield In Maize, M. A. B. Fakorede, J. J. Mock Jun 2017

Correlated Responses To Recurrent Selection For Grain Yield In Maize, M. A. B. Fakorede, J. J. Mock

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Experiments were conducted in three field environments with the following objectives: (1) to evaluate the progress from seven cycles of reciprocal recurrent selection in Iowa Stiff Stalk Synthetic (BSSS(R)] and Iowa Corn Borer Synthetic #1 (BSCBl(R)] and six cycles of half-sib family selection in 'Alph' (i.e., BS12) maize (Zea mays L.) populations, (2) to compare the response of unimproved and improved maize variety hybrids to different levels of nitrogen fertilizer and plant density, and (3) to evaluate the influence of nitrogen and plant density on the morphological and physiological traits associated with recurrent selection for grain yield ...


Comparison Of Meadow-Kill Treatments On A Corn-Oats-Meadow-Meadow Rotation In Northwestern Iowa, R. P. Mowers, W. A. Fuller, W. D. Shrader Jun 2017

Comparison Of Meadow-Kill Treatments On A Corn-Oats-Meadow-Meadow Rotation In Northwestern Iowa, R. P. Mowers, W. A. Fuller, W. D. Shrader

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

An experiment was conducted at the Moody Research Center (formerly Moody Experimental Farm) in northwestern Iowa to examine the effects of meadow-kill on crop yields and on soil moisture in the spring. The experiment utilized a corn-oats-meadow-meadow rotation with meadow-kill treatments applied to the second-year meadow at various times of the growing season. Twenty years (1958-1977) of data were used for the analyses presented in this bulletin.

Three treatments were used in the experiment. In the first, the control treatment, the second-year meadow was harvested two or three times. The plots were plowed the following spring before corn was planted ...


Chemical Composition Of Sewage Sludges In Iowa, M. A. Tabatabai, W. T. Frankenberger Jr. Jun 2017

Chemical Composition Of Sewage Sludges In Iowa, M. A. Tabatabai, W. T. Frankenberger Jr.

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Knowledge of the chemical composition of sewage sludges produced by wastewater treatment plants in Iowa is essential for future attempts to recycle this material on agricultural land. Sewage sludges produced by treatment plants in 44 Iowa communities, ranging in population from < 1,000 to >50,000, were analyzed for 30 constituents to survey the quality of the sludges and to assess the potential of this material as a source of plant nutrients for crop production in this region. Results showed that, expressed on an oven-dry basis, the median values of organic C, and total N, P, K, and S were 31, 2.6 ...


Selection Procedures In The Development Of Maize Inbred Lines And The Effects Of Plant Densities On The Relationships Between Inbred Traits And Hybrid Yields, W. A. Russell, Veronica Machado Jun 2017

Selection Procedures In The Development Of Maize Inbred Lines And The Effects Of Plant Densities On The Relationships Between Inbred Traits And Hybrid Yields, W. A. Russell, Veronica Machado

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The purpose of this research was to use five selection procedures to develop inbred lines of maize (Zea mays L.):

(1) to compare the selected lines for performance per se and in testcrosses at various plant densities, thereby evaluating the selection procedures; and

(2) to determine the effects of plant densities on the relationships among plant, ear, and grain traits of the inbred lines and between these traits and hybrid yield performance.

The source population was an Iowa Synthetic, BS1. Five groups of lines were obtained: Group 1, selected visually at a density of 59,000 plants/ha in rows ...


Range And Forage Research Needs For Red Meat Production In The North Central Region, S. A. Ewing, Herman J. Gorz Jun 2017

Range And Forage Research Needs For Red Meat Production In The North Central Region, S. A. Ewing, Herman J. Gorz

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The 12 contiguous states of the North Central Region constitute one of the most productive agricultural areas in the world. Before the region was settled, vegetation consisted primarily of forest in the east, grasses in the west, and an intermingling of grass and forest in the central portions. Although the region contains a high proportion of productive soils, there are great differences within the region in soils, as well as in climate, vegetation, and geology. The short-grass soils in the western areas are higher in pH, lighter in color, and thinner than the tail-grass soils in the central and west-central ...


Missouri River History, Floodplain Construction, And Soil Formation In Southwestern Iowa, R. V. Ruhe, T. E. Fenton, L. L. Ledesma Jun 2017

Missouri River History, Floodplain Construction, And Soil Formation In Southwestern Iowa, R. V. Ruhe, T. E. Fenton, L. L. Ledesma

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The Platte River has influenced the Missouri River below the mouth of the Platte by contributing sizable suspended and coarser-textured bed loads. Consequently, the Missouri River has been and is a braided stream in a reach about 43 miles long below the mouth of the Platte. In this reach the channel is wider, is less sinuous, has greater low-water slope profile, and contains numerous bars and islands. The Otoe Bend area, in this reach of the Missouri River near the southwestern corner of Iowa, has inherited these channel characteristics.

By use of historic maps and aerial photographs, the lateral shifting ...


Available-Sulfur Status Of Some Representative Iowa Soils, John P. Widdowson, John J. Hanway Jun 2017

Available-Sulfur Status Of Some Representative Iowa Soils, John P. Widdowson, John J. Hanway

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Greenhouse experiments with ryegrass were conducted to evaluate and characterize plant availability of native and added sulfur in samples of Iowa soils. Fourteen surface soil (0-6 inches) and five subsoil (18-24 inches) samples from different sites in Iowa and two surface soil samples from S-deficient out-of-state sites were studied. Laboratory analyses were made to characterize the soil samples and to evaluate the results of different extractants as indexes of the S-supplying abilities of the soils. Plant uptake of S from the soil samples with no added S during a 202-day cropping period (five harvests) varied from 1 to 39 mg ...


Analysis Of Crop-Rotation Experiments, With Application To The Iowa Carrington-Clyde Rotation-Fertility Experiments, G. E. Battese, W. A. Fuller, W. D. Shrader Jun 2017

Analysis Of Crop-Rotation Experiments, With Application To The Iowa Carrington-Clyde Rotation-Fertility Experiments, G. E. Battese, W. A. Fuller, W. D. Shrader

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

This report presents a model by which several crop rotations are compared, and optimal fertilization and rotation practices determined. The model is developed with specific applicability to the rotation- fertility experiments at the Carrington-Clyde Experimental Farm near Independence, Iowa. The substitutability of legume meadow and chemical nitrogen fertilizer and the effect of carry-over of applied nitrogen from crop to crop are incorporated into the analysis. The split-plot nature of the rotation- fertility trials is noted, and a transformation of the yield data is employed to create nearly uncorrelated observations. Response functions are estimated for each crop in each rotation. Optimal ...


Response In Yield And Leaf Composition Of Soybean Varieties To Phosphorus, Potassium, And Calcium Carbonate Materials, C. J. Demooy, John Pesek Jun 2017

Response In Yield And Leaf Composition Of Soybean Varieties To Phosphorus, Potassium, And Calcium Carbonate Materials, C. J. Demooy, John Pesek

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Yield responses of soybeans [Glycine Max (L.) Merrill] to phosphorus and potassium fertilizers have the reputation of being small and inconsistent unless the soil tests low to very low with respect to these elements. Consequently, soybean fertilization is commonly left to the residual effect of fertilization of other crops in the rotation such as corn. Field experiments were conducted with the general objective to investigate means whereby the magnitude and consistency of soybean responses to fertilization may be improved.

Differential responses exist in corn. Jones (18) concluded that some inbred lines have a lower K requirement than others and also ...


Plant Availability Of Added Phosphorus In Different Iowa Soils, Oetit Koswara, John J. Hanway Jun 2017

Plant Availability Of Added Phosphorus In Different Iowa Soils, Oetit Koswara, John J. Hanway

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Laboratory and greenhouse experiments were conducted to study the availability of fertilizer P in 20 samples of different soils representing 10 of the principal soil associations in Iowa.

Ryegrass plants recovered an average of approximately 50 percent of the added fertilizer P during a 385-day cropping period in the greenhouse. It appeared that continued cropping would have resulted in very little additional recovery of the added P. Differences in recovery of the added P from the different soils were relatively small, despite differences in rate of fertilizer addition or differences in soil pH, CaCO3 content, level of available soil ...


Advance Of Irrigation Water On The Soil Surface In Relation To Soil Infiltration Rate: A Mathematical And Laboratory Model Study, Mohamed Asseed, Don Kirkham Jun 2017

Advance Of Irrigation Water On The Soil Surface In Relation To Soil Infiltration Rate: A Mathematical And Laboratory Model Study, Mohamed Asseed, Don Kirkham

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Mathematical equations describing the horizontal advance of an irrigation stream on a soil surface are derived and discussed for different types of infiltration equations corresponding to different known field conditions. Complex variable theory is applied to transform certain complicated forms of infiltration equation solutions to algebraic forms. An irrigation model having a visible Plexiglas photographic front was constructed and operated to test the theory and obtain data not covered by the theory. Glass beads or soil aggregates constitute the porous medium; water is used as the seepage fluid. Potassium dichromate dye is injected into the porous medium to trace the ...


Interrelationships Of Plant Population, Soil Moisture And Soil Fertility In Determining Corn Yields On Colo Clay Loam At Ames, Iowa, C. E. Beer, W. D. Shrader, R. K. Schwanke Jun 2017

Interrelationships Of Plant Population, Soil Moisture And Soil Fertility In Determining Corn Yields On Colo Clay Loam At Ames, Iowa, C. E. Beer, W. D. Shrader, R. K. Schwanke

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

This investigation included a 6-year study of the effects of irrigation, stand and fertility treatments on com yields on a clay loam soil near Ames, Iowa. The data obtained from 1956 to 1961 indicated that variations in yields were caused by all three variables. Significant yield differences caused by irrigation treatments were greatest in 1956, 1959 and 1960. The highest mean irrigated yields averaged over stand and fertility treatments usually correlated best with the irrigation treatment where the soil moisture was maintained at or above 60 percent of the available moisture content (AMC). The greatest yield response to irrigation occurred ...


Fertilizer Production Functions In Relation To Weather, Location, Soil And Crop Variables, John T. Pesek Jr., Earl O. Heady, Eduardo Venezian Jun 2017

Fertilizer Production Functions In Relation To Weather, Location, Soil And Crop Variables, John T. Pesek Jr., Earl O. Heady, Eduardo Venezian

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

This study is based on several long-term experiments of crop fertilization at three Iowa locations: Howard County, with Clyde and Cresco soils; Hancock County, with acid and calcareous Webster soils; and Wayne County, with Seymour soil. The trials at these widely separated experimental farms included corn and oats fertilized in a 3-year rotation of corn-oats-meadow. The periods of the trials were: Clyde and Cresco soils, 1945-1960; Webster soils, 1954-1960; Seymour soil, 1949-60. Although meadow was not fertilized, residual nutrients from fertilization of the oats nurse crop were expected to affect hay yield. Applied nutrients included only phosphorus and potassium.

The ...


Selection In Zea Mays L. By Inbred Line Appearance And Testcross Performance In Low And High Plant Densities, W. A. Russell, A. H. Teich Jun 2017

Selection In Zea Mays L. By Inbred Line Appearance And Testcross Performance In Low And High Plant Densities, W. A. Russell, A. H. Teich

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The development of inbred lines and the search for their best hybrid combinations are the main bases of corn improvement in the United States. The most commonly used method for inbred development is to enforce self fertilization for several generations while practicing visual selection for the more highly heritable characteristics. During these generations, surviving stocks maintained on an ear-to-row basis become highly homozygous and highly homogeneous. Because' evaluation for combining ability by using test-cross procedures is expensive, it is usually delayed until after three to five generations of visual selection. Visual selection for combining ability among inbred progenies is rarely ...


Postglacial Environments In Relation To Landscape And Soils On The Cary Drift, Iowa, Patrick H. Walker Jun 2017

Postglacial Environments In Relation To Landscape And Soils On The Cary Drift, Iowa, Patrick H. Walker

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The objectives of this study were to evaluate environmental and time factors in the genesis of soils and soil landscapes on the Cary drift in Iowa, with special reference to soils of the Clarion toposequence.

The stratigraphy of five bogs along the Des Moines lobe was studied in detail; and as a result, a general bog stratigraphy was established for the Cary drift in Iowa. The stratigraphic zones and appropriate radiocarbon dates are as follows: upper muck zone (UM), 0-3,000 years; upper silt zone (US), 3,000- 8,000 years; lower muck zone (LM), 8,000-10,500 years; lower ...


Comparisons Of Laboratory And Greenhouse Indexes Of Nutrient Availability In Soils, John J. Hanway, Turgut Ozus Jun 2017

Comparisons Of Laboratory And Greenhouse Indexes Of Nutrient Availability In Soils, John J. Hanway, Turgut Ozus

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Accurate indexes of the availability to plants of nutrients in soils are needed for comparisons of different chemical tests to determine which tests should be used in the laboratory for any given group of soils. This study was conducted to develop and improve techniques for obtaining such standard indexes of nutrient availability to plants. Emphasis was placed on: (a) treating the soil similarly (or uniformly) before testing in the greenhouse and laboratory and (b) avoiding treatments during the greenhouse cropping that might influence the availability of the soil nutrient being tested.

The greenhouse technique involved growing plants on undried samples ...


Fertilizer Production Functions From Experimental Data With Associated Supply And Demand Relationships, Earl O. Heady, John T. Pesek, V. Y. Rao Jun 2017

Fertilizer Production Functions From Experimental Data With Associated Supply And Demand Relationships, Earl O. Heady, John T. Pesek, V. Y. Rao

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

This study includes (1) estimation of physical production functions from fertilizer experiments designed for this purpose, (2) prediction of corresponding marginal products, isoquants and isoclines, (3) estimation of economic optima under various price situations, (4) prediction of confidence regions for isoquants, isoclines and economic optima, (5) derivation of static corn supply and fertilizer demand functions and (6) estimation of gross marginal rates of substitution of fertilizer for land.

The analysis of this study is based on two sets of experiments conducted in 1959 and 1960 on corn. The experiments, conducted on Clarion, Nicollet and Webster soil series, included nitrogen (N ...


Yield Response Of Corn In A Planosol Soil To Subsurface Drainage With Variable Tile Spacings, C. E. Beer, H. P. Johnson, W. D. Shrader Jun 2017

Yield Response Of Corn In A Planosol Soil To Subsurface Drainage With Variable Tile Spacings, C. E. Beer, H. P. Johnson, W. D. Shrader

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The Edina soil series of southeastern Iowa and northern Missouri are soils of relatively flat topography and poor internal drainage. The need for research data on the feasibility of drainage (both surface and subsurface) on the Edina soils was recognized at the time experiments were begun on the Southern Iowa Experimental Farm, Davis County, Iowa. The yield response of corn to surface drainage by bedding was summarized and reported by Beer et al.3 in 1961. Since initiation of the subsurface drainage experiment in 1949, data on crop-yield response to tile drainage have been collected. The purpose of this bulletin ...


The Influence Of Nitrogen And Phosphorus Ferilization On Nutrient Status And Profitability Of Bromegrass On Ida Soils, W. C. Moldenhauer, G. V. Holmberg, J. T. Pesek, L. C. Dumenil, J. J. Hanway Jun 2017

The Influence Of Nitrogen And Phosphorus Ferilization On Nutrient Status And Profitability Of Bromegrass On Ida Soils, W. C. Moldenhauer, G. V. Holmberg, J. T. Pesek, L. C. Dumenil, J. J. Hanway

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

This study was undertaken to determine the profitability and the feasibility of fertilizing bromegrass for grazing in the Monona-Ida-Hamburg soil association area. This area is well adapted to growing forage crops. Because of the high content of calcium and potassium, alfalfa grows well if phosphorus is applied. Bromegrass is able in some way to get nitrogen from alfalfa, and the two crops grow well together. The bloat danger in pasturing alfalfa or bromegrass-alfalfa mixtures, however, is well known to cattlemen in the area. Many believe the cost of nitrogen fertilizer to maintain productivity of bromegrass pastures is less than the ...


Soybean Yields And Plant Composition As Affected By Phosphorus And Potassium Fertilizers, R. J. Miller, J. T. Pesek, J. J. Hanway, L. C. Dumenil Jun 2017

Soybean Yields And Plant Composition As Affected By Phosphorus And Potassium Fertilizers, R. J. Miller, J. T. Pesek, J. J. Hanway, L. C. Dumenil

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The primary objective of this study was to determine if soybean grain yields could be predicted by the P and K content of the growing plant. A supporting objective was to find what plant parts should be taken, and at what stage of growth, to give the best relationship. Multiple curvilinear regression analysis was used to determine this relationship from data collected in four field experiments.

Yields, chemical composition of soybean plant parts and other data were available from four similar fertilizer experiments conducted at various locations in Iowa in 1958. A randomized block 9 x 9 central composite design ...


Solving Tile Drainage Problems By Using Model Data, Ben L. Grover, Don Kirkham Jun 2017

Solving Tile Drainage Problems By Using Model Data, Ben L. Grover, Don Kirkham

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Our purpose in this bulletin is to report, to analyze, and to use in problem solving, extensive model data of tile drainage of land.

The data were obtained with a glassbead-glycerol model (Grover et al., 1960; Grover and Kirkham, 1961) and inc1ude: (a) values of depths and of corresponding times of fall of the surface of saturation to these depths at various distances from the drain tubes and (b) values of the drain tube discharge rates. The zero reference time for the fall of the surface of saturation and also for the discharge rate is the instant at which the ...


Role Of Nitrogen, Phosphorus And Potassium Fertilizers In Continuous Corn Culture On Nicollet And Webster Soils, A. J. Englehorn, John Pesek, W. D. Shrader Jun 2017

Role Of Nitrogen, Phosphorus And Potassium Fertilizers In Continuous Corn Culture On Nicollet And Webster Soils, A. J. Englehorn, John Pesek, W. D. Shrader

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The possibility of growing continuous corn is receiving increasing consideration with the changing agricultural patterns. Farmers are devoting more and more acres to intensive cropping sequences in which corn follows corn more often. The practice of continuous corn-growing consecutive corn crops on the same land-is on the increase. This is because corn is the most profitable crop generally grown in the Corn Belt, because limitations in production technology have been eased, and because farm product demands or values have altered.

Early research with crop rotations generally resulted in conclusions that continuous culture of inter tilled crops, especially of corn, was ...


Estimation Of Soil Moisture Under Corn, R. H. Shaw Jun 2017

Estimation Of Soil Moisture Under Corn, R. H. Shaw

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

This study was undertaken as an attempt to develop a simplified approach to a complex problem- the prediction of soil moisture under corn which, at times, may have a limited moisture supply. Soil moisture under corn was estimated for June, early August and early November by using April, June and August soil-moisture survey data as the starting points. All computations were made on the basis of the amount of plant-available water present. To obtain this value, both the field capacity and the wilting point of a soil need to be known. Precipitation amounts were added to the data for soil ...


Profit-Maximizing Plans For Soil-Conserving Farming In The Spring Valley Creek Watershed In Southwest Iowa, Jay C. Andersen, Earl O. Heady, W. D. Shrader Jun 2017

Profit-Maximizing Plans For Soil-Conserving Farming In The Spring Valley Creek Watershed In Southwest Iowa, Jay C. Andersen, Earl O. Heady, W. D. Shrader

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The purpose of this study is to determine whether farmers in the Spring Valley Creek Watershed in Mills County, Iowa, can profitably conserve their soil to an increased extent. These farmers presently fall far short of conservation goals of public agencies. Although the conservation goals are stated in terms of preventing loss of topsoil, closely related problems of gullying, flooding and channel siltation are important. Solution of these interrelated problems is stressed by the activities of various governmental agencies. The need for control of the headwaters and tributary streams was recognized in Public Law 566-the Small Watershed Act. The limited ...


Production Functions And Methods Of Specifying Optimum Fertilizer Use Under Various Uncertainty Conditions For Hay, Earl O. Heady, John T. Pesek, W. Owen Mccarthy Jun 2017

Production Functions And Methods Of Specifying Optimum Fertilizer Use Under Various Uncertainty Conditions For Hay, Earl O. Heady, John T. Pesek, W. Owen Mccarthy

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Farmers who use fertilizer on a crop are concerned with at least two uncertainty problems relating to the amount of fertilizer that maximizes profits. Both of these problems arise, in part, from weather, a common underlying cause. First, crop yield is uncertain. Thus, a quantity of fertilizer applied, with the decision made before planting, may not be optimum for the yield actually obtained. Second, at the time of planting, future crop use or price may also be indefinite. The value of hay, for example, may differ according to the method of utilization. Hence, a particular amount of fertilizer applied in ...


Beef-Cattle Production Functions In Forage Utilization, Earl O. Heady, Glenn P. Roehrkasse, Walter Woods, J. M. Scholl Jun 2017

Beef-Cattle Production Functions In Forage Utilization, Earl O. Heady, Glenn P. Roehrkasse, Walter Woods, J. M. Scholl

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Little information has existed on substitution rates between pasture forages and corn in a beef-fattening enterprise. Without this knowledge it is difficult to determine which combinations of pasture forage and com would maximize profits. Profits in feeding depend not only on the cost of feed but also on the time of marketing. The pasture forage-corn ration that minimizes costs may not necessarily be the ration that maximizes profits, since profits are affected by the time of marketing. Both the quality and the price of beef are subject to change during the beef-fattening period. Consequently, the beef-cattle feeder is confronted with ...


Effects Of Light And Soil Moisture On Forest Tree Seedling Establishment, G. E. Gatherum, A. L. Mccomb, W. E. Loomis Jun 2017

Effects Of Light And Soil Moisture On Forest Tree Seedling Establishment, G. E. Gatherum, A. L. Mccomb, W. E. Loomis

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The present studies were designed to aid in the solution of forest tree seedling establishment problems common to stand conversion practices in Iowa. The primary objectives were: (1) to determine the minimum treatment needed to insure successful survival and growth; (2) to study the relationships of light and soil moisture in plant competition resulting from stand conversion; and (3) to evaluate five species of conifers - European larch, Scotch pine, eastern white pine, Norway spruce and red pine - for adaptability to region, site and underplanting.

Field studies were made at the Brayton Forest in northeastern Iowa and consisted of ( 1 ) practical ...


North Central Regional Potassium Studies Iii. Field Studies With Corn, J. J. Hanway Jun 2017

North Central Regional Potassium Studies Iii. Field Studies With Corn, J. J. Hanway

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

Corn is sensitive to a deficiency of potassium (K),2 and yields of corn on K-deficient soils often are increased by K fertilizer applications. K deficiencies in corn have been observed or yield increases have been obtained from K fertilizer applications on many soils in the North Central Region of the United States. However, many other soils in the region have high levels of available K, and applications of K fertilizers on these soils have not increased corn yields. Therefore, it is important to have effective methods of estimating plant availability of K in different soils and to develop methods ...


Response Of Corn Yields In A Planosol Soil To Surface Drainage, Cropping System And Variable Fertilizer Treatments, C. E. Beer, H. T. David, W. D. Shrader Jun 2017

Response Of Corn Yields In A Planosol Soil To Surface Drainage, Cropping System And Variable Fertilizer Treatments, C. E. Beer, H. T. David, W. D. Shrader

Iowa Agriculture and Home Economics Experiment Station Research Bulletin

The Edina soil series of southeastern Iowa and northern Missouri are areas of relatively flat topography and poor internal drainage. For these areas, where the topography and soils permit, surface drainage is the most practical method of removing excess water from the land. One method of surface drainage that has been used on the Edina soils is bedding, in which the field is divided into narrow-width plow lands with the deadfurrows running parallel to the prevailing land slope.

Little is known about the relative returns from investment in a bedding system in comparison with other surface or subsurface drainage methods ...