bluuebunny/crossref_metadata_2025_split huggingface dataset:
DDT and Toxaphene Movement in Surface Water from Cotton Plots
Authors: Bradley J. R. , Sheets T. J. , Jackson M. D. 
Published: July 2010

AbstractWhen 13.4 kg/ha of DDT were applied to cotton (Gossypium hirsutum L.) during the 1969 growing season, 2.83% was found in natural runoff between July 11, 1969 and January 5,1970. About 96% of the DDT in runoff was associated with suspended sediment. Of 26.8 kg/ha of toxaphene applied, 0.36% was detected in runoff, and 75% of the toxaphene in runoff was in the sediment fraction. When DDT and toxaphene were applied to the same plot (13.4 and 26.8 kg/ha, respectively, over the season) only 1.03% of the DDT was found in runoff, and the percentage for toxaphene was 0.61. A much greater percentage of DDT and toxaphene remained as soil residues than was found in runoff, but a high percentage of the pesticides applied was not recovered. Residues of DDT in water from a small pond within one experimental watershed ranged from <0.35 ppb before spraying to 13.4 ppb during the spraying season. Toxaphene residues in pond water varied from <1 ppb before spraying to 65 ppb about midseason.
Tolerance and Susceptibility of Kentucky Bluegrass (Poa pratensis L.) Cultivars to Air Pollution: In the Field and in an Ozone Chamber
Authors: Wilton A. C. , Murray J. J. , Heggestad H. E. , Juska F. V. 
Published: July 2010

AbstractDuring late summer and autumn of 1970, differential injury, believed to be due to air pollution, was observed on five Kentucky bluegrass (Poa pratensis L.) cultivars: ‘Merion’, ‘Kenblue’, ‘Windsor’, ‘117‐27‐6’, and ‘Belturf’. Belturf was injured most, 117‐27‐6 least, and the other three cultivars were intermediate as to injury. Damage was less severe on parts of plots fertilized with N at 293 kg/ha than on parts of plots fertilized with 146.5 kg/ha of N.Subsequent tests of three of these cultivars in an ozone chamber (30 pphm 2 and 4 hours) showed cultivar injury ratings corresponding to field injury ratings. Belturf was most severely injured, Windsor next, and 117‐27‐6 least. Differences among cultivars were highly significant at both levels of ozonation. Injury was significantly greater when ozone was applied at 30 pphm for 4 hours, than at the same level for 2 hours. The 117‐27‐6 was unique in that it tolerated ozone considerably better than did previously investigated Kentucky bluegrass cultivars. The chance selection of this extremely tolerant cultivar was possibly related to its having been selected from M3 progeny of irradiated Merion seed.This ozone experiment also indicated that bluegrass may build up some tolerance to repeated ozone treatments.
Agriculture, Man, and His Environment
Authors: Bentley Orville G. 
Published: July 2010

AbstractThe relationship between the scientific and social aspects of environmental problems imposes responsibilities and constraints on both scientist‐educators and laymen. Scientists now have much of the technological knowledge needed to help clean up the American environment, but pollution control can be successful only if Americans are made aware of and accept the tremendous social and dollar costs involved. In some way, every American will be affected in the process of implementing solutions to pollutional problems. The problem for the businessman is whether the public will buy his product if he spends millions on his plant to reduce pollution, and then passes this “social” cost on to the consumer in the form of higher prices for products. Caution is needed, for some small businessmen may be forced out of business if strict enforcement of pollution controls call for production changes that the small businessman cannot afford. In the area of the quality of life, public universities must make education available to all who are qualified for it, and should help produce social leaders who can reside in and help resolve the problems of violence‐torn communities. A list is presented of seven environmental problem areas in which colleges of agriculture are conducting or should conduct research.
Agriculture's Contribution to Open Space and Natural Beauty
Authors: Skinner Henry T. 
Published: July 2010

AbstractIn addition to the economic, recreational, or conservation values of open spaces of our rural and urban landscapes, we can no longer afford to ignore the factors of esthetics. As an item of increasing public concern, esthetics pegs open spaces at values which call for new methods of prediction and calculation. A major element of open space, of natural beauty, and of esthetics, is plant life: the trees, shrubs, and groundcovers of the hillside, the home lot, and the city street.A review of plant cultural problems, especially problems of the artificial urban environment, points up need for discovering superior plants or for breeding improved ones. Improvements involve upgraded quality for esthetic effect, adaptability to man‐made environments, but especially the increase of resistance to pests of diverse kinds and to pollutants of the air and soil. A recently “remade” London plane (Platanus acerifolia) or sycamore (Platanus) tree, likely to be both pest‐ and pollution‐resistant, provides an example of manufactured plants of this sort.An urgent need of the 1970's is for the development of workable programs designed to preserve and protect the total values of the countryside—agricultural, conservation, scenic, and recreational—on a countywide, statewide, and nationwide basis. Within these objectives, the environmentalist is concerned for the threatened species of animals and plants. But our concern should go further. Within the species, it is the variant individual which can become immensely valuable as genetic studies progress, and which, when identifiable, should not be lost.
Role of Plants in Improving the Environment
Authors: Waggoner Paul E. 
Published: July 2010

AbstractFoliage, especially foliage that is well watered and rapidly taking in carbon dioxide, improves our environment in tangible ways as well as aesthetically. Properly arranged, foliage can shade us without stilling the breeze and thus balance our energy budgets comfortably. When the productivity of crops per acre is increased, this frees land for parks and wilderness. Plants can also heal scarred land and scavenge pollutants from waste. Finally, we have recently learned that foliage can take in air pollutants, and the estimated cleansing of the air is considerable.
An Interpretation of Reservoir Sedimentation: I. Effect of Watershed Characteristics
Authors: Paulet Manuel , Kohnke Helmut , Lund L. J. 
Published: July 2010

AbstractThe value of a water storage reservoir can decrease rapidly if its capacity is reduced by settling of eroded and suspended soil. Many factors determine the rate of this “siltation.” The purpose of this paper is twofold: to analyze to what extent the influence of the characteristics of the soils of the contributing watershed upon rate and type of sedimentation of reservoirs can be assessed quantitatively and to determine how these effects are correlated with other geomorphological factors.This study was made on 14 reservoir‐watershed combinations in Indiana and Illinois. The majority of the soils were silt loams. Under the conditions of this study, as the mean particle size decreases and the more uniform their particle size, the greater were the sedimentation rates. Sediment volume weight was found to be a function of particle size and organic matter content. The larger the mean particle size and the smaller the organic matter content of the sediment, the greater was the bulk density. The variation of sediment particle size and sedimentation rates could be evaluated quantitatively as functions of geomorphological and pedologic watershed characteristics.
Nitrification in Sediments of Selected Wisconsin Lakes
Authors: Chen R. L. , Keeney D. R. , Konrad J. G. 
Published: July 2010

AbstractNitrification rates in lake sediment‐water systems were investigated in the laboratory. Samples from Wisconsin eutrophic and oligotrophic hard‐ and soft‐water lakes were incubated at 10C or 25C in the dark using nonstirred (i.e. quiescent) and stirred (magnetic stirrer) systems open to the atmosphere. Nitrate was not formed in the acid sediments from soft‐water lakes. However, in calcareous sediments from hard‐water lakes, nitrification proceeded readily when the systems were stirred to increase oxygen diffusion. Nitrate did not accumulate when the samples were not stirred. Experiments with N‐Serve indicated that autotrophic organisms were mainly responsible for nitrification in the Lake Mendota samples.Considering the high oxygen diffusion rate required for nitrification in sediments, it is likely that this process occurs only at the sediment‐water interface in oxygenated waters.
Denitrification and Nitrate Reduction in Wisconsin Lake Sediments
Authors: Chen R. L. , Keeney D. R. , Graetz D. A. , Holding A. J. 
Published: July 2010

AbstractThe fate of 15N‐labelled NO3‐N in Wisconsin lake sediment‐water systems was investigated in laboratory and field experiments. In the laboratory, approximately 90% of the added NO3‐N disappeared from a calcareous sediment (Lake Mendota) compared to about 40% from a noncalcareous sediment (Trout Lake) after 48 hours when incubated under He. About 10% (Mendota) and 5% (Trout) of the added NO3‐N was recovered as organic‐N and NH4‐N. The presence of significant amounts of 15NH4‐N, particularly in Lake Mendota sediment, indicated that immobilized N was subject to rapid mineralization. Nitrate‐15N not accounted for was assumed lost through denitrification. Under aerobic conditions 10% (Mendota) and 2% (Trout) of the 15N was recovered as organic N but little 15N appeared in the NH4‐N fraction.In a field investigation, 15NO3‐N, added to Lake Mendota sediment samples and returned to the lake bottom in wide‐mouth plastic bottles, disappeared within 4 days. After 4 days about 37% of the added NO3‐N was in the organic and NH4‐N fractions, while the remaining 63% was likely lost through denitrification. These data illustrate that denitrification and NO3‐N reduction in sediments receiving NO3‐N in ground waters must be evaluated in calculating nitrogen budgets of seepage lakes.
Lead Uptake by Lettuce and Oats as Affected by Lime, Nitrogen, and Sources of Lead
Authors: John Matt K. , Van Laerhoven C. 
Published: July 2010

AbstractUptake of lead by lettuce (Lactuca sativa L.) and oats (Avena sativa L.) as a result of application of lime, nitrogen, and various sources of lead to the soil was studied in a growth chamber experiment. Soil application of lead increased the uptake of lead by lettuce to a greater degree than by oats. Application of lime repressed the uptake of added lead by both plants, while application of low levels of nitrogen reduced the uptake of lead by lettuce and oat roots only. Application of lead chloride lowered the amount of sulfur and phosphorus in plants, but levels of other elements studied were not affected by any lead treatment.
Nitrogen Balance in Soil Columns Intermittently Flooded with Secondary Sewage Effluent
Authors: Lance J. C. , Whisler F. D. 
Published: July 2010

AbstractShort, frequent cycles of flooding soil columns (2 days flooded and 5 days dry) with secondary sewage effluent caused no net removal of N but transformed almost all of the N to nitrate. The net N removal during longer cycles (9–23 days flooded and 5 days dry) was 30%, and half of the N remaining in the water was concentrated into a wave of high‐nitrate water, which represented 10% of the total volume of reclaimed water and was collected immediately after the dry period. Water collected from the columns after the wave of high‐nitrate water passed contained 67% less N than the incoming sewage water.Alternate flooding and drying periods were necessary for consistent N removal. The net N removal was probably due to a combination of several reactions dominated by denitrification. Cation exchange was important in holding NH4+ in the soil until it could be nitrified, thereby concentrating N into smaller volumes of high‐nitrate water. Denitrification is the logical reaction to investigate for higher net N removal because the soil microorganisms nitrified most of the NH4+ and N can be removed from the system as an inert gas by denitrification.
Molybdenum Availability as Influenced by Application of Fly Ash to Soil
Authors: Doran J. W. , Martens D. C. 
Published: July 2010

AbstractRelationships between fly ash application to soil and Mo availability were evaluated by greenhouse and laboratory procedures. Seventeen samples of fly ash under study ranged from 5.6 to 39.3 ppm in total Mo content. Thirteen of the fly ash samples were alkaline in reaction, and these samples neutralized from 0.01 to 3.74 meq H3O+/g. Incorporation of two samples of fly ash, which contained the extremes in the range of total Mo content, increased alfalfa (Medicago sativa L.) yield on an acidic Groseclose silt loam. The increase in yield was attributed to alleviation of toxicities associated with low levels of soil pH. Molybdenum uptake data indicated approximately equal availability of Mo in fly ash and in Na2MoO4·2H2O.
Copper Toxicity in Snapbeans (Phaseolus vulgaris L.)
Authors: Walsh L. M. , Erhardt W. H. , Seibel H. D. 
Published: July 2010

AbstractA 2‐year field experiment was conducted to determine whether Cu applied for pathogen control could accumulate to a level that would be toxic to snapbeans (Phaseolus vulgaris L.). Copper sulfate and Cu(OH)2 were applied at rates varying from 0 to 486 kg/ha Cu on a Plainfield loamy sand to approximate 1, 3, 9, and 27 years of fungicidal treatment. Correlation and regression analyses were used to compare the amount of Cu extracted from the soil by 3 extraction procedures (0.1N HCI, EDTA, and DTPA) with crop yield and the concentration of Cu in snapbean tissue.Rates of up to 54 kg/ha Cu had no deleterious effect on the yield of snapbeans in either year. Slight yield decreases were noted when the rate of Cu exceeded 130 kg/ha, and a marked reduction in yield occurred when 405 kg/ha of Cu as Cu(OH)2 or 486 kg/ha of Cu as CuSO4 was applied. Yield decreases were similar the 1st and 2nd years after Cu application, indicating that Cu toxicity was not being ameliorated over a 2‐year period of time. Soil Cu and yield were highly correlated for each of the extraction methods. Based on the regression equations, a significant yield depression was obtained when HCI or DTPA‐extractable Cu exceeded 20 ppm, and when EDTA‐extractable Cu exceeded 15 ppm. Soil Cu extracted by each extraction procedure was highly correlated with Cu in the leaf tissue, especially for the immature first trifoliate leaf. Yield reductions were noted when the Cu concentration in the seedling trifoliate increased from 20 to 30 ppm, and severe toxicity was observed at tissue concentrations in excess of 40 ppm Cu.
Genetics of Disaster
Authors: Harlan Jack R. 
Published: July 2010

AbstractErosion of some of the most vital resources for human survival goes on with no notice from the public and very little attention from the scientific community, which should be better informed. The germ plasm base required for improvement of the basic food crops that feed the world is being rapidly destroyed. This destruction of genetic resources is caused primarily by the very success of modern plant breeding programs.
Fungicidal Management of Pathogen Populations,
Authors: Rowell J. B. 
Published: July 2010

AbstractFungicides are the only means of controlling disease epidemics in a susceptible crop when conditions favor a virulent fungal pathogen that produces air‐borne spores rapidly and abundantly. Most available fungicides are surface protectants that act externally on the host to prevent infection by the pathogen. A high percentage of the plant tissue must be protected because large amounts of inoculum are produced by small numbers of infections. Maintenance of a protective chemical deposit effective throughout the vulnerable period of crop development requires frequent fungicidal spray applications of relatively high dosages. In contrast, systemic fungicides now under development act within the host and control disease with one or two applications at low dosages. Many of these materials are highly selective; they are effective against specific groups of pathogens. Some systemic fungicides suppress epidemics of rust and mildew diseases when applied as seed or soil treatments at planting. Such fungicides have great potential for preventing severe disease epidemics in field crops threatened by virulent, aggressive fungal pathogens.
Stabilizing Racial Populations of Plant Pathogens by Use of Resistance Genes
Authors: Nelson R. R. 
Published: July 2010

AbstractVertical resistance (VR) genes in plants function by restricting the infection site and the infection process of parasites. Such genes are effective against certain races and ineffective against others. Horizontal resistance (HR) genes in plants function by reducing the amount of disease by reducing disease increase. Horizontal resistance is effective to some extent against all races. The use of resistance genes to curb population shifts is examined herein. It is probable that HR curbs population shifts by virtue of its polygenic inheritance which requires that the parasite obtain and accumulate a number of new virulence genes. The use of VR genes in multilines holds some promise, deployment of VR genes probably does not, and pyramiding of VR genes seems most worthy. The concept of stabilizing selection is presented, discussed, evaluated, and deemed of doubtful validity as a means of curbing racial shifts.
New Concepts in Chemical Seed Treatment of Agronomic Crops
Authors: Futrell Maurice C. 
Published: July 2010

AbstractThe presence of Helminthosporium maydis Nisik. & Miyaka race T in corn (Zea mays L.) seed reduced germination and vigor of the seedlings. Ten percent of the seedlings damped‐off in soil in a growth room. Treating seed with Vitavax (5, 6‐dihydro‐2‐methyl‐1, 4‐oxathiin‐3‐carboxanilide) and Vitavax‐Thiram (Tetramethylthiurum disulfide) reduced the activity of H. maydis in the seed. Benomyl [Methyl 1(butylcarbamoyl)‐2‐benzimidazolecarbamate] and thiobendazole [2(4‐thiazolyl)‐benzimidazole] arrested Fusarium moniliforme Sheldon infection in corn seed. Mixtures of Vitavaxthiram and benomyl were effective in controlling both species of fungi in seed.
Southern Leaf Blight of Corn—Present Status and Future Prospects
Authors: Hooker A. L. 
Published: July 2010

AbstractTwo races, T and O, of Helminthosporium maydis Nisikado & Miyake cause southern blight of corn (Zea mays L.). The new race T spread widely in the USA in 1970 and to a lesser extent in 1971. It produces a pathotoxin specific to cms‐T cytoplasm of corn plants and infects the leaf, leaf sheath, husk, and ear parts. Race O, normally confined to the warmer parts of the USA, does not produce a specific pathotoxin and infects leaves primarily. Other races may exist or appear in the future.Resistance to race O is based on nuclear genes, and in most sources is quantitative in expression and polygenic in inheritance; one source with recessive gene inheritance expresses chlorotic lesions with reduced fungus sporulation. Resistance to race T is both cytoplasmic and nuclear. Normal cytoplasms and many cytoplasms for male‐sterility such as the cms‐C and cms‐S types are highly resistant in the field. Resistance in cms‐T cytoplasm is partial and probably due to the same nuclear genes that give resistance to race O.A diversity of cytoplasms within hybrids and the selection of high levels of nuclear‐gene resistance in a stalk rot resistant background are suggested as breeding and seed production objectives.
Soil Nitrogen Balance in selected Row‐Crop Sites in Southern California
Authors: Adriano D. C. , Takatori F. H. , Pratt P. F. , Lorenz O. A. 
Published: July 2010

AbstractNine row‐crop sites, where data for nitrogen fertilizer use, crop yields, and amounts of irrigation water used were available for a number of years, were studied to estimate the N balance as related to NO3− in water in the unsaturated zone from below the zone of root influence to the water table or to the 15‐m depth.The system of predicting NO3− concentrations in drainage waters based on the difference between N inputs and N removal in harvested crop sand the drainage volume in which the excess N, converted to NO3−, is dissolved, was valid in open‐porous soils containing no layers that restrict water movement within the soil profile (0‐ to 2‐m depth). A combination of losses plus net immobilization of up to 56% had to be assumed in some soils to account for all the N loss. In two soils that had been used for disposal of feedlot manure, net mineralization of N from the organic N pool had to be assumed to explain the data obtained.The current fertilization and irrigation practices used for some row crops in southern California leave varying amounts of NO3− in the drainage water. The amounts depend on the total N added, crop removal, drainage volume, net mineralization, and losses.
Cadmium Absorption and Growth of Various Plant Species as Influenced by Solution Cadmium Concentration
Authors: Page A. L. , Bingham F. T. , Nelson C. 
Published: July 2010

AbstractSolution culture techniques were used to study the response of corn, turnips, beets, beans, tomatoes, cabbage, lettuce, green peppers, and barley to Cd levels in solution in the range of 0.1 to 10 µg/ml. Tolerance of the plants to Cd varied. Growth of beets, beans, and turnips was reduced by 50% at Cd solution concentrations of 0.2 µg/ml. Similar growth reductions for corn and lettuce occurred where the solution concentration level was about 1 µg Cd/ml. Tomatoes and barley were somewhat more tolerant with levels of about 5 µg Cd/ml required to produce 50% growth reduction. Cabbage, the most tolerant plant species tested, showed 50% growth reduction at Cd solution concentrations of 9 µg/ml.Cadmium concentrations of plant leaves increased as the amount of Cd added to the substrate solution increased. Amounts accumulated when the solution concentration was 0.1 µg/ml varied between 9 µg/g (bean leaves) and 90 µg/g (corn leaves). At solution concentrations of 1.0 µg Cd/ml the range was 35 µg/g (bean leaves) to 469 µg/g (turnip leaves). Similarly at 10 µg Cd/ml the range was 175 µg/g (barley) to 112 µg/g (tomato leaves). The results presented show that plants vary in their tolerance to Cd solution levels and their leaves are capable of accumulating excessive Cd amounts when the solution concentration is of the order of a few tenths of a µg/ml.
Lead Availability Related to Soil Properties and Extractable Lead
Authors: John Matt K. 
Published: July 2010

AbstractLead content of lettuce (Lactuca sativa L.) and oats (Avena saliva L.) was related to lead extracted from 29 contaminated soils by several different extraction procedures. Correlation studies showed that 1N nitric acid extractable lead was significantly related to lead in lettuce; however, milder extraction with 0.01N nitric acid and 1N ammonium acetate provided a better correlation with lead content of oat shoots and roots. Soil properties, particularly soil pH, were also important when attempting to predict plant lead. Lead availability was related to soil pH, extractable aluminum, and total nickel. No relationship with organic matter was observed.