Showing papers in "Journal of Environmental Quality in 1973"

An Open-Top Field Chamber to Assess the Impact of Air Pollution on Plants

Abstract: Reasonable air pollution control policies depend upon a comparison of the costs of air pollution losses with the costs of controls. Present estimates of national economic losses to agricultural and ornamental vegetation are based primarily on field observations and partially on growth and yield data obtained from closed-top field chambers and greenhouses. This research describes the design and evaluation of an open-top field chamber that was developed to provide an environment more closely resembling ambient conditions than the environment found in closed-top chambers. Temperature and relative humidity within open-top chambers were similar to ambient conditions. Direct sunlight reached the plants for a portion of each day and rain entered, although not always uniformly over the chamber base. Chambers receiving charcoal-filtered air protected sensitive ‘Bel W₃’ tobacco plants (Nicotiana tabacum L.) from ambient ozone concentrations. Plants growing in chambers receiving unfiltered air or in ambient air plots were severely injured.

Significance of pH and Chloride Concentration on Behavior of Heavy Metal Pollutants: Mercury(II), Cadmium(II), Zinc(II), and Lead(II)

Abstract: Calculations were performed (i) to assess the degree to which Hg(II), Cd(II), Zn(II), and Pb(II) complex with hydroxyl and chloride ions and (ii) to evaluate the significance of such complexation in natural systems. Results indicate that both the hydroxy and chloride complexes may contribute to the mobilization of these heavy metal ions in the environment. Hydrolysis of Hg(II) becomes important at pH values above 1 whereas Pb(II), Zn(II), and Cd(ll) hydrolyze above pH 5, 7, and 8, respectively. Chlorides complex with Hg(II) at chloride concentrations above 10⁻⁹M (35 × 10⁻⁶ ppm). HgCl₂ forms above 10⁻⁷.⁵M Cl⁻(1.1 × 10⁻³ ppm), and HgCl₃⁻ and HgCl₄²⁻ formation occurs above 10⁻²M Cl⁻(350 ppm). The MCl⁺ species of Zn(II), Cd(II), and Pb(II) appear at chloride concentrations above 10⁻³M (35 ppm), and MCl₂ complexes occur above 10⁻²M (350 ppm Cl⁻). The respective MCl₃⁻ and MCl₄²⁻ species become important above 10⁻¹M Cl⁻(3,500 ppm). Hydrolysis and chloride complexation of these heavy metal ions are important factors affecting the solubility of the sparingly soluble salts of these metal ions. This is most pronounced for mercuric salts. Intrinsic solubilities of the metal-ion hydroxides allow for 160 ppm Zn(II) and 107 ppm Hg(II) to be soluble as complexed Zn(OH)₂ and Hg(OH)₂, respectively. These values are higher than calculated solubilities based on solubility products. An example of the competition between hydroxy and chloride complexes shows that at pH 8.5 and a chloride concentration range of 350–60,000 ppm, Hg(II) and Cd(II) are mainly complexed by chlorides. Zn(II) and Pb(II), under these conditions, are predominantly in the form of hydroxy complexes.

Cadmium Uptake by Plants

Abstract: Absorption of /sup 115m/Cd by soybean (Gylcine max l.) plants via foliar and root systems and translocation into the seed was determined. The uptake of /sup 115m/Cd by soybeans via the root system was more efficient than that of the foliar placement. Growth and Cd concentrations of soybean and wheat (Triticum aestivum l.) tops were influenced by soil-applied Cd. In both crops, the Cd concentration of plant tops increased while yield decreased with increasing levels of applied Cd. Cadmium toxicitiy began to occur in both crops at the lowest level of soil applied Cd (2.5 ppM). With soybean plants, Cd toxicity symptoms resembled fe chlorosis. For wheat plants there were no visual symptoms other than the studied growth. The relative concentration of Cd found in several vegetable crops varied depending on the plant species. The relative Cd concentration in descending order for various vegetables was lettuce (Lactuca sativa l.) > radish top (Raphanus sativus l.) > celery stalk (Apium graveolens l.) > celery leaves greater than or equal to green pepper (Capsicum frutescens l.) > radish roots.

The Nitrogen Cycle in Sediment-Water Systems

Abstract: The available literature on the fate of nitrogen in waters and sediments is reviewed. Emphasis is placed on the importance of N to aquatic productivity, the pathways leading to N gains or losses in aquatic ecosystems, and the availability of N in sediments to the overlying waters. Important biological reactions include N mineralization and immobilization, nitrification and denitrification, and N fixation. The effect of sediment properties, lake morphology and environmental factors (pH, temperature, dissolved oxygen, oxidation-reduction potential) on the pathways and rates of turnover are considered. The mixing process in sediments appear to be the most important in releasing sediment-N to waters. Several facets of the N cycle in waters and sediments require further elucidation. Research needs are outlined.

Nitrogen Tracers in Nitrogen Cycle Studies—Past Use and Future Needs

Abstract: Nitrogen research is directed toward two main objectives, food and fiber production and environmental control. To achieve N balance in productive ecosystems, better quantitative estimates of N transformation rates are needed. Nitrogen tracers are indispensable for making many of these estimates. Either / sup 15/Ndepleted or /sup 15/N-enriched materials can be used. The use of /sup 15/ Ndepleted materials is limited to studies where dilution from other N is less than 2,000-fold, but these materials are potentially available in ton amounts. Use of variations in natural /sup 15/N abundance may be useful in observing qualitative relationships among N cycle processes over large areas or extremely long time periods. Such use is questionable for obtaining quantitative information for short-term N transformation processes. Obvious information gaps are quantitative data on atmospheric N/sub 2/ fixation and denitrification in cropped field soils and N transformation data for many other ecosystems. A program for computer data retrieval and correlation is outlined.

Nitrogen Transformations During Subsurface Disposal of Septic Tank Effluent in Sands: I. Soil Transformations

Abstract: Soil physical and chemical studies of five subsurface septic tank seepage beds were conducted to determine the biochemical transformations of N and thereby its potential for ground-water pollution. Effluent was found to be ponded in all the seepage beds examined due to the presence of an impeding layer, a “crust”, at the boundary between the gravel bed and adjacent soil. The crust reduced infiltration rates approximately from 500 to 8 cm/day. Soil atmospheric composition 5 cm below the crust averaged 19.6% O₂ and 0.66% CO₂. Nitrogen in the septic tank effluent occurred as NH₄-N (80%) and organic N (20%) with virtually no NO₃-N. Organic-N was largely concentrated in the crust zone. Nitrification of NH₄-N to NO₃-N was essentially complete and commenced in the unsaturated subcrust soil within about 2 cm of the crust. Nitrification did not occur and NH₄-N was absorbed by the soil below a seepage bed that was submerged in the ground water.

Nitrogen Losses in Surface Runoff from Agricultural Watersheds on Missouri Valley Loess

Abstract: Nitrogen losses from surface runoff from four field-size (30 to 60.8 ha) watersheds in southwestern Iowa, near Treynor, were measured during 1969, 1970, and 1971. A contour-planted corn watershed and a pasture watershed were fertilized at the recommended N rate (168 kglha). A level-terraced and a contour-planted corn watershed were fertilized at 2.5 times this rate. The conservation practice of level-terraced corn or pasture was very effective in reducing water, sediment, and N yields when compared with the contour-planted corn watersheds. Annual water-soluble N losses were low from all watersheds. The Byear average annual solution N loss from the contourplanted corn watershed, fertilized at 2.5 times the recommended rate, was 3.05 kglha; the comparable watershed, fertilized at the recommended rate, lost only 1.89 kglha. Nitrogen losses associated with sediment in the runoff accounted for 92% of the total loss for the Byear period from the contourplanted corn watersheds. A large portion of the N loss for the terraced watershed was also associated with the sediment; however, N loss was only one-tenth that of the contour-planted watersheds. Sediment-N concentrations were similar for watersheds receiving 168 kglha and 448 kglha annual N applications. Water-soluble-N and sediment-N losses in runoff were usually highest at the beginning of the cropping season and decreased progressively throughout the year, reflecting a seasonal effect believed to be associated with nutrient removal by the crop, leaching, and N tie-up in organic matter. Additional Index Words: fertilizer, sediment, erosion. nitrate content of water resources, since accumulations can be hazardous to human health (8). Nitrogen concentrations in excess of 10 ppm NO3-N have been found in water supplies during the period that use of commercial fertilizers has increased rapidly (1 3). Viets (15) points out that circumstantial evidence indicates waterquality deterioration should be associated with increased fertilizer use, but positive evidence is not available. Nitrogen losses in runoff from agricultural lands and forested areas have been reported by many researchers (2, 10, 11). Losses from forested areas generally range from less than 1 to 3.36 kg/ha and represent land areas that have been affected least by man's activities (5, 7). Timmons et al. (14) found N losses as high as 14.5 kg/ha per year from corn-cropped plots. These losses were affected greatly by the management practices used. Total N loss was much greater from nonfertilized, cultivated fallow and normally fertilized, continuous corn than from land in a 3-year rotation receiving normal, annual fertilization.The sediment in the runoff contained most of the N lost. The present study provides information on N losses in surface runoff from field-size agricultural watersheds (30 to 61 ha) as related to conservation management practices, rate of N fertilizer application, and seasonal differences in climate. Much public attention has been focused recently on enMATERIALS AND METHODS vironmental quality as influenced by agricultural practices. considerable interest has centered around the The four experimental watersheds are located in southwestern Iowa near Treynor. The topography of the area is characterized by . a loess cap, underlain by till, ranging in thickness from 24.4 m on 'contribution from the Agricultural Research Service, USDA, the ridges to less than 4.6 m in the valleys. Gully and sheetdl in with the Nebraska and Iowa Agr. Exp. Puberosion are serious problems, and many valleys have deeply incised lished as Paper No. 3400, Journal Series, Nebraska Agr. EXP. Sta., channels that extend upstream to an active gully head, Linzcoln 68503. Received July 10, 1972. Soil Scientist, USDA, Lincoln, Nebr.; Soil Scientist, USDA, Principal soil types are Marshall, Monona. Ida, and Napicr silt council ~ l ~ f f ~ , lows; ~ ~ d ~ ~ l ~ ~ i ~ Engineer, USDA, Columbia, MO.; loams. These loessial soils have good internal drainage. Slopes on and Agricultural Engineer, USDA, Council Bluffs, Iowa, respecthe watersheds range from 2 to 4% on the ridges and bottoms to 12 tively. to 18% on the sides (1 2). J. Environ. Quality, Vol. 2, no. 2,1973 299 The four watersheds were instrumented in 1964 to measure precipitation and streamflow. Precipitation measurements were obtained from recording raingages strategically located on each watershed. Streamflow discharge was measured by waterstage recorders used with calibrated broad-crested, V-notch weirs. Watershed size, crop, conservation practice, and fertilizer application are shown in Table 1. Watersheds 2 and 3 received the normal, recommended fertilizer applicationrates of 168 kg N/ha and 39 kg Plha in 1969, 1970, and 1971. Anhydrous ammonia was'knifed in to a depth of 25 to 35 cm on 100-cm row spacings, and P was broadcast and plowed down on Watershed 2. All fertilizer (NH4N03 and superphosphate) was broadcast on the sod surface of the bromegrass pasture on Watershed 3. Watersheds 1 and 4 received a high fertilizer application rate of 448 kg N/ha annually. A high rate of 97 kg P/ha was applied to these watersheds in 1969 and 1970, but the P fertilizer application rate was reduced to 39 kg P/ha in 1971. For these highfertility watersheds, anhydrous ammonia was knifed in to a 25to 30-cm depth on 50-cm shank spacings a t the rate of 389 kg Nlha in 1969 and 1971. An additional 59 kg N/ha as NH4N03 was broadcast and plowed down as a part of the preplant tillage operations on these watersheds. In 1970, only 60% of the N was applied as anhydrous ammonia, whereas 91% was applied as anhydrous ammonia in 1969 and 1971. The additional N was broadcast as NH4N03. Potassium was applied at the rate of 28 kg K/haannually on all watersheds. All fertilizer was applied in the spring before preplant tillage operations. All corn watersheds were harvested for grain and the stalks left on the watershed. The corn watershed yields ranged from 6780 to 8537 kglha. The pasture watershed also had considerable residues and animal wastes remaining in the fall after grazing by cattle during the summer. Animal numbers on pasture varied from 75 to 130 and grazed the pasture from May to November. Therefore, residue was present on all watersheds during the winter and precropping period. Approximately 500 ml of the soil-water runoff mixture was collected manually a t time intervals during each surface runoff event to determine the concentrations of sediment, NO3-N, NH4-N, and sediment N. Samples were usually collected a t the gully headcut site on Watersheds 1 and 2 and at the weir site on Watersheds 3 and 4. Gully headcut samples represent sheet-rill erosion from the cropland area, and weir samples represent sheet-rill plus gully erosion. The gullies on Watersheds 3 and 4 have been inactive, and samples collected at the weir represent cropland area discharges. Samples were collected during the rise, peak, and recession of streamflow for most surface runoff events. A minimum of four samples was collected for each sampled event. Samples were stored at 4C to minimize chemical and microbiological conversions. The liquid and solid phases were separated by Whatman No. 423 filter p a p a and checked by centrifugation to insure that the liquid was free of colloidal material. Ammonia-N and nitrate-N were determined on the clarified solution by steam distillation with MgO and Devarda's alloy into boric acid and titration with dilute H2S04 (3). A Technicon ~ u t o ~ n a l ~ z e r ~ was obtained in July 1970 w ~ t h which NH4-N and NO3-N were then determined, using continuousflow colorimetric procedures (1,9). The sediment content of each sample was determined gravimetrically, the sediment dried at 60C for 24 hours, then ground to 3 ~ a m e of product is listed for benefit of the reader only and does not imply endorsement or preferential treatment by the USDA. Table I -Watershed description, crop, conservation practice, and fertilizer application rates for 1969, 1970, and 1971, Treynor, lowa WplerConaervatlon Fertllher shed Size C ~ P prnctlce N P

Nitrogen Transformations and Availability of an Anaerobically Digested Sewage Sludge in Soil

Abstract: Samples (50 g) of Warsaw sandy loam soil (Typic Argiudoll) were incubated under aerobic conditions with varying levels of an anaerobically digested sewage sludge (up to 1,880 ppm N on an oven-dry soil basis). Total N, NH₄-N, (NO₃+NO₂)−N, NH₃ volatilization, and hydrolyzable forms of N were determined periodically during 16 weeks of incubation at room temperature (23 ± 3C). At low levels (≤ 235 ppm N), the inorganic N was all converted to (NO₃+NO₂)-N while at the higher levels (≥ 940 ppm N), a significant amount of NH₄-N was not nitrified even after 16 weeks of incubation. Recovery of added N was nearly quantitative at the low levels of sewage sludge addition. However, at the higher levels, there was evidence of concurrent nitrification-denitrification. The hydrolyzable N distribution results indicated that very little of the hydrolyzable N was mineralized at the low rates of application. At the high rates of application, apparent development of anaerobic conditions led to more rapid mineralization of the sewage sludge organic N than was found under aerobic conditions. The data indicate that from 4 to 48% of the organic N in the sewage sludge was mineralized to (NO₃+NO₂)−N in 16 weeks. Thus, the availability of sewage sludge organic N must be considered when evaluating the potential of the material as a fertilizer or a possible source of NO₃-N to ground waters.

Effect of Soil Application of Dairy Manure on Germination and Emergence of Some Selected Crops

Abstract: Germination and emergence of sudangrass (Sorghum sudanense Stapf ‘Piper’), barley (Hordeum vulgare L. ‘Numar’), radish (Raphanus sativus L. ‘Cherry Belle’), and spinach (Spinacea oleracea L. ‘Bloomsdale’) in a glasshouse were investigated using a Chino loam soil where various amounts (0, 5, 10, 15, and 20% dry manure by weight) of dairy manure were added. The degree of germination injury depended on the crop species and rate of application or the salt and N inputs. The crop sensitivity to salt or NH3 were as follows: barley < sudangrass and spinach < radish. Barley and sudangrass were more tolerant to salt or NH3 than spinach and radish. Barley germination data from treatments which had NaCl added to the soil extracts to obtain the same osmotic potential as those treated with urine, urea, or manure suggest that the germination injury was not salt specific and that other compounds such as NH3 were also contributing factors. Germination injury can be minimized by planting several days after soil application of large amounts of dairy or feedlot manure to allow volatilization of a significant quantity of NH3 or after adequate preirrigation, or both.

Chemical and Biochemical Considerations for Maximizing the Efficiency of Fertilizer Nitrogen

Abstract: Fertilizer nitrogen is subject to loss from the soil-root zone, and immobilization by the soil and rhizosphere microfloras, which can result in low recovery and use efficiency of the applied nitrogen. With increasing rates of application, fertilizer nitrogen efficiency decreases progressively, while leaving an increasing amount of unused nitrogen as a potential pollution hazard. Since the point of greatest economic return from this nutrient is usually somewhere below the point of maximum yield, it should be possible to adjust fertilizer nitrogen rates for maximum return and minimum loss to the environment. This can be achieved through improved soil and crop management practices, including proper timing of application of conventional nitrogen fertilizers and use of deep-rooted crops for recovery of leached nitrate. A rational approach to more meaningful nitrogen recommendations is needed, one which would account for residual fertilizer nitrogen and mineralizable soil nitrogen, and allow an accurate prediction of the amount of supplemental fertilizer nitrogen necessary to produce the desired yield. Efficiency of fertilizer nitrogen might also be increased with controlled release fertilizers, including the use of coated granules, and compounds of limited water solubility blended with conventional nitrogen fertilizers, to achieve a specific release rate coincident with the nitrogen requirements of a crop. Formulation of ammoniacal fertilizers with nitrification inhibitors offers considerable opportunity for increasing fertilizer nitrogen efficiency.

Pelletized Municipal Refuse Compost as a Soil Amendment and Nutrient Source for Sorghum

Abstract: The handling, processing, and disposal of solid waste have reached such proportions in the USA as to constitute one of our major environmental problems. Over 480 million metric tons of solid waste are discarded annually by American citizens. In the past, most of this waste was burned in open dumps or deposited in mismanaged landfills. Because of air and water pollution, more satisfactory methods must be developed for solid waste disposal. Composting with efficient machinery under sanitary conditions shows promise in helping to solve this problem. The end product of composting has value as a soil amendment and contains nutrients which are available for plant use. The objective of this study was to evaluate a pelletized compost of much improved physical conditions as compared to other composted municipal refuse. Pelletized compost was used in a greenhouse study as a soil amendment and plant nutrient source after incorporation in Arredondo sand. The application of 8 metric tons/ha of compost increased the yields of two sorghum (Sorghum bicolor L. Moench) crops as compared to the control. Also, the highest rate of compost (64 metric tons/ha) produced higher yields as compared 10-4.4-8.3 fertilizer at 2 tons/ha. Uptake of all plant nutrients measured, except for Mn, was increased by compost applications. In addition, water retention and cation exchange capacity of the Arredondo sand were generally increased by compost applications

Nitrogen-15 Enrichment of Soils and Soil-Derived Nitrate

Abstract: Nitrogen-isotope analysis of soils and soil-derived nitrate showed (i) that there is considerable variation in the /sup 15/N enrichment ( DELTA /sup 15/ N) of the nitrate nitrogen produced on aerobic incubation of different soils and (ii) that the DELTA /sup 15/N of this nitrate nitrogen depends upon the time of incubation and can differ markedly from that of the total soil N. The data reported illustrate the impracticability of a recently proposed method of assessing the contribution of fertilizers to nitrate in surface waters that requires measurement of the natural /sup 15/N enrichment of soil- and fertilizer- derived nitrate. (auth)

Experimental and Predicted Movement of Three Herbicides in a Water-Saturated Soil

Abstract: The equilibrium adsorption characteristics of 1,1-dimethyl-3-(a,a,a-trifluoro-m-tolyl) urea (fluometuron), 4-amino-3,5,6-trichloropicolinic acid (picloram), and 2,4-bis(isopropylamino)-6-(methylthio)-s-triazine (prometryne) on Ca-saturated Norge loam soil were measured and were found to fit the Freundlich equation. A solution of each herbicide was displaced through a water-saturated colume of Norge loam soil at various average pore-water velocities (5.6 to 0.57 cm/hour) and effluent samples evaluated to determine the importance of adsorption kinetics to the mobility of the herbicide. The displacement of each herbicide through the soil was significantly influenced by the average pore-water velocity. The use of a kinetic adsorption model in a convective transport equation did not adequately predict the shape of the effluent concentration distribution at the high pore-water velocities, but did give the left-hand shift exhibited by the data. The tailing noted in all the herbicide effluent concentration distributions resulted primarily from the nonsingularity between the adsorption-desorption process. Equilibrium adsorption and desorption isotherms were measured for picloram on Ca-saturated Norge loam soil.

Chemical Distribution of Residual Fertilizer Nitrogen in Soil as Revealed by Nitrogen-15 Studies

Abstract: Chemical distribution patterns were obtained for the residual N in field plots previously amended with ¹⁵N-labeled urea and oxamide. From 25 to 40% of the fertilizer N was present in the soil (0 to 25 cm) after the first growing season, about half of which still remained after 5 years. Essentially all of the fertilizer-derived N (97.0%) occurred in organic combination; only a small fraction (3.0%) was accounted for in inorganic forms, chiefly as fixed NH₄⁺. In comparison to the native humus N, higher percentages of the fertilizer N left after the first growing season occurred as amino acids (52.0 vs. 33.7%) and amino sugars (8.2 vs. 7.5%); lower percentages occurred in acid-insoluble forms (9.0 vs. 15.2%), as acid-hydrolyzable organic NH₃ (9.0 vs. 17.0%), and as unidentified acid-soluble N (8.8 vs. 20.3%). Considerable humification occurred during the subsequent 4 years with relocation of amino acids N (and possibly amino sugar-N) to more resistant humus forms. The findings suggest that fertilizer N, once incorporated into soil organic matter, becomes increasingly stable with time and is not readily mineralized or subject to leaching.