Search

Use of organic by-products as soil amendments in agricultural production exemplifies a strategy for converting wastes to resources. The overall objective of this research was to evaluate the short- and intermediate-term effects of repeatedly amending sandy soil with paper mill residuals (PMR) and composted PMR in a vegetable rotation in Wisconsin's Central Sands. Specifically, we investigated the effects of PMR and composted PMR on total soil C and related these to changes in water-holding capacity and plant-available water (PAW). Amendment effects on irrigation requirements were estimated with a simple soil water balance model. The experimental design was replicated five times as a randomized complete block with four organic amendments: raw PMR, PMR composted alone (PMRC), PMR composted with bark (PMRB), and peat applied at two rates and a non-amended control. All amended treatments significantly increased total soil C relative to the nonamended control following applications in 1998 and 1999. One year following the second serial amendment, all PMR treatments increased PAW by 5 to 45% relative to the control. There was a significant positive linear relationship between total soil C and PAW. All amended treatments reduced the average amount of irrigation water required for potato production by 4 to 30% and the number of irrigation events by 10 to 90%. There was a clear trend of greater reduction in irrigation requirements with more carbon added. The cumulative effects of repeated additions of PMRB suggest that certain composts might sustain elevated PAW and reduce irrigation requirements beyond one year.

This study was conducted to establish an appropriate mixture ratio of fly ash (F) to optimized cow dung-waste paper mixtures (CP) to develop a high-quality vermicompost using earthworms (). Fly ash was mixed with cow dung-waste paper mixtures at ratios of (F:CP) 1:1, 1:2, 1:3, 2:1, and 3:1 or CP alone and composted for 14 wk. Olsen P, inorganic N (NO, NO, and NH), C:N ratio, ash content, microbial biomass C, and humification parameters were measured together with scanning electron micrograph images to determine compost maturity. Based on C:N ratio, the extent of vermidegradation of the waste mixtures followed the decreasing order (F:CP) of 1:31:21:1CP alone2:13:1. Similarly, Olsen P was significantly higher (0.05) where earthworms were added. The mean percentage increase in extractable P was in the order CP alone1:21:31:12:13:1, with earthworm addition almost doubling P release across the 1:1, 1:2, and CP alone treatments. Fly ash incorporation enhanced conversion of organic N to the plant-available inorganic forms, with the 1:3 treatment resulting in the highest conversion. Scanning electron micrograph images confirmed the extent of vermidegradation reflected by the various humification parameters determined. Fly ash incorporation at the 1:2 ratio proved to be the most appropriate because it allows processing of more fly ash while giving a vermicompost with desirable maturity and nutritional properties.

Hydrothermal carbonization allows rapid conversion of biomass into a carbon-rich, lignite-like product (hydrochar). It is assumed to have beneficial effects on soil properties and plant growth, but detailed studies are lacking, especially in the field. The objective of our study was to investigate the effect of hydrochar incorporated into arable soils on soil mineral nitrogen (N) content and sugar beet growth. In 2010-2011, a field and a pot trial were conducted. Hydrochars (field: 10 Mg ha; pot: equivalent to 30 Mg ha) processed from sugar beet pulp (HSP) and beer draff (HBD) were tested against an untreated control. As a second factor, mineral nitrogen (N) fertilizer level (field: 0, 50, 100, 150 kg N ha; pot: 0, 100, 200 mg N kg soil) was varied. In both trials, hydrochars reduced initial sugar beet growth, especially when hydrochar with a high C/N ratio (38, HSP) was combined with a low N fertilizer level; high N supply partly compensated for the reduced seedling growth. Without N fertilization, no extractable N was present at the end of the pot trial in the HSP treatment, whereas in HBD even more N was extracted than in the control. This suggests remineralization of previously immobilized N when hydrochar with a low C/N ratio was applied (16, HBD). In the field, beet yield was equal at the high N fertilizer level in HSP and at all N levels in HBD treatment. Our results suggest that hydrochar can decrease plant-available N due to N immobilization. Other potential causes for the observed early growth reduction need to be studied more in detail.

The objectives of this study were to determine the effect of bedding material (corn stover, soybean stover, wheat straw, switchgrass, wood chips, wood shavings, corn cobs, and shredded paper) on concentration of odorous volatile organic compounds (VOC) in bedded pack material and to determine the effect of bedding material on the levels of total in laboratory-scaled bedded manure packs. Four bedded packs of each bedding material were maintained for two 6-wk periods ( = 64). Straight- and branched-chained fatty acids and aromatic compounds were measured. Corn cob bedding had the highest concentration of odorous VOC, and wood shavings had the lowest ( < 0.01). Calculated odor activity values were highest for corn cob bedding and shredded paper and lowest for wood shavings ( < 0.01). concentrations decreased from week to week for all treatments from Week 2 to Week 6. At Week 6, levels in bedded packs with shredded paper were higher ( < 0.05) than bedded packs containing wood shavings, wood chips, or switchgrass ( < 0.05). At Weeks 4, 5, and 6, concentrations in bedded packs with wood shavings were lower ( < 0.05) than bedded packs of all treatments except wood chips. Results of this study indicate that ground corn cobs or shredded paper may increase odor production and shredded paper may increase when used in deep-bedded livestock facilities, whereas wood shavings may have the least impact on air quality and .

A soil microcosm experiment was used to analyze effects of depleted uranium (DU) on soil function, and the concomitant changes in bacterial functional diversity. Uranium treatment levels were 0, 50, 500, 5000, 10,000 and 25,000 mg DU kg{sup {minus}1} soil. Three measures of soil function were made. Overall soil biological activity was assessed via measurement of soil respiration. Decomposition was assessed by measurement of mass loss of four different plant litter types: wood sticks, cellulose paper, high-N grass, and low-N grass. Mineral N availability in the microcosms was estimated using ion-exchange resin bags. Functional diversity of the microcosms was analyzed through the use of the Biolog-system of sole-C-utilization patterns. Soil respiration was the most sensitive measure of functional changes, with significant decreases observed starting at the 500 mg kg{sup {minus}1} treatment. No differences in N availability were observed across the U treatments. Litter decomposition was significantly decreased at the 25,000 mg kg{sup {minus}1} level relative to the control for all litter types except the high-N grass. Wood decomposition was reduced by 84% at the 25,000 mg kg{sup {minus}} treatment, cellulose paper by 68%, and low-N grass by 15%. Decreases in the functional diversity of the bacterial community were related tomore » the observed decrease in soil respiration, and to the greater effect on decomposition of the lower-quality litter types.« less

Although it is widely agreed that stocking density critically affects the rate of vermicomposting, there is no established stocking density for mixtures of fly ash and other waste materials. This study sought to optimize (Savigny, 1826) stocking density for effective biodegradation and nutrient release in a fly ash-cow dung-waste paper (FCP) mixture. Four stocking densities of 0, 12.5, 25, and 37.5 g worms kg were evaluated. Although the 12.5, 25, and 37.5 g worms kg treatments all resulted in a mature vermicompost, stocking densities of 25 and 37.5 g worms kg resulted in faster maturity, higher humification parameters, and a significantly lower final C/N ratio (range 11.1-10.4). The activity of β-glucosidase and fluorescein diacetate hydrolysis enzymes showed faster stabilization at stocking densities of 25 and 37.5 g worms kg, indicating compost stability and maturity. Similarly, a stocking density of 25 g worms kg resulted in the highest release of Olsen-extractable P and (NO + NO)-N contents. The 0-, 12.5-, 25-, and 37.5-g treatments resulted in net Olsen P increases of 16.3, 38.9, 61.0, and 53.0%, respectively, after 10 wk. Although compost maturity could be attained at stocking densities of 12.5 g worms kg, for faster production of humified and nutrient-rich FCP vermicompost, a stocking density of 25 g worms kg seems most appropriate.

Methane capture and use from intensive livestock industries is relatively new, and there is limited chemical and kinetic degradation information available for beef feedlot manure in Australia or internationally. This paper evaluates the biochemical methane (CH4) potential, apparent first-order hydrolysis rate coefficient, and losses in organic content of manure as it ages on feedlot pads and in stockpiles. Chemical characterization of fresh, pad, and stockpiled manure is assessed. Biochemical CH4 potential on volatile solids (VS) almost always decreased significantly from fresh to pad and from pad to stockpile, ranging (in mL CH4 g VS−1fed) from 230 to 360 in fresh manure, from 70 to 280 in pads, and from 60 to 200 in stockpiles. Kinetics of degradation also varied with manure age (fresh: 0.12 ± 0.01 d−1; pad: 0.06 ± 0.02 d−1; and stockpiled: 0.05 ± 0.04 d−1). At least 50%, and up to 80%, of the original biochemical CH4 potential of the manure (i.e., degradable material) was lost on drying in pads, and the loss after stockpiling was much greater (>85%). The loss of N was 15 to 60% as manure dried on pads and was much greater after stockpiling (40–90%). Phosphorus loss, though lower than nitrogenous losses, was still significant (25–65% on pads and 35–85% in stockpiles). Although digestion of stockpiled manure is still feasible to generate energy, collection of fresh manure is important to maximize outcomes, with a possible order of magnitude increase in CH4 production achievable.

The pastoral grazing of farmed red deer (Cervus elaphus) is common in New Zealand. However, red deer have a natural instinct to seek out water and wallow in it. Often, in headwater catchments, they will create a wallow in a wet area connected to a waterway. Aesthetically, wallowing areas can be unpleasant and give the impression they are significant sources of contaminants entering waterways. This paper aimed to quantify their contribution to loads of contaminants lost from three headwater catchments (4.1 to 32.1 ha). Monthly water samples were taken of base flow and of all storm flow events and analyzed for nitrogen (N) and phosphorus (P) species, suspended sediment (SS), and the fecal indicator bacteria-E. coli. Median concentrations were generally in excess of recommended guidelines for lowland water quality and contact recreation in New Zealand (guidelines=9 microg dissolved reactive P L(-1), 30 microg total P L(-1), 444 microg nitrate and nitrite N L(-1), 0.9 mg NH4+-N L(-1) at pH 7, 4 mg SS L(-1), and 260 cfu 100 mL(-1)). Loads of P (up to c. 3 kg P ha(-1)) and SS (up to 4.5 Mg ha(-1)) exceeded the highest loads measured (1.7 kg P and 2 Mg SS ha(-1)) for a range of pastoral catchments in New Zealand, including deer-farmed catchments without many wallows connected to waterways. More losses occurred during storm flow than base flow but, more importantly, the majority of losses only occurred when deer were in the paddock and wallowing. Hence, to mitigate most contaminant losses, management should focus on discouraging wallowing and/or breaking the connectivity between wallows and waterways.

Construction of wetlands is a possible supplement to best management practices (BMP) at the field level to mitigate phosphorus (P) pollution from agricultural areas. In this paper, annual results from 17 intensively studied wetlands in the cold temperate or boreal climatic zone are reported and analyzed. Surface areas varied from 0.007 to 8.7% of the catchment area. The average total phosphorus (TP) retention varied from 1 to 88%, and the dissolved reactive phosphorus (DRP) retention from -19 to 89%. Retention varied substantially from site to site, indicating the existence of site-specific factors in the catchment and wetlands that influenced the P removal. Factors important for P retention in wetlands were evaluated through multiple statistical analyses by dividing P into two fractions: particulate phosphorus (PP) and DRP. Both relative (%) PP and DRP retention increased with wetland surface area. However, PP retention was not as sensitive as DRP in terms of wetland size and retention: specific PP retention (gram P retention per m(2) and year) decreased as wetland area (A(w)) increased, suggesting the existence of a site-specific optimal wetland to catchment area (A(c)) ratio. Particulate P retention decreased with increasing DRP to TP ratio, while the opposite was found for DRP. Dissolved reactive P retention was higher in new than in old wetlands, while increasing age did not influence PP retention negatively. Effective BMP in the catchment is important to keep the P loss low, because the outlet concentration of P from wetlands is often positively correlated to the input concentration. However, wetlands act as the last buffer in a catchment, since the retention often increases as the P concentration in streams increases.

Received for publication October 29, 2004. Cost effective feeding strategies are essential to deal with P surpluses associated with intensive animal agriculture and the consequent impact on water quality. Reduction of P overfeeding, use of feed additives to enhance dietary P utilization, and development of high available phosphorus (HAP) grains have all been shown to decrease fecal P excretion without impairing animal performance. Much progress has been made, but more research will be needed to refine these strategies to maximize reductions in P excretion while maintaining animal performance. Recent research has focused on the impact of modifying dietary P on the forms of P excreted and the mobility of P in soils amended with these manures, with strong treatment trends becoming evident in the literature. In general, dietary strategies have been developed that can effectively reduce the total P concentration in manures produced, and combining strategies usually leads to greater reductions than individual practices. However, the impact of different approaches on the solubility of P in manures and amended soils has been more variable. Soluble P remains of particular concern due to links between solubility of P in manure and P losses from manure-amended soils. In this paper, we outline the major strategies for reducing dietary P in different species, review the literature on the impact of these approaches on P forms in manures and amended soils, and discuss the potential beneficial effects on animal agriculture and the environment.

Ammonia (NH3) from confined animal feeding operations is emitted from several sources including lagoons, field applications, and houses. This paper presents studies that were conducted to evaluate NH3 emissions from swine finisher and sow animal houses in the southeastern USA. Management and climate variables including animal weight, feed consumption, housing gutter water temperature, total time fans operated per day, house air temperature, house ambient NH3 concentration, and animal numbers were measured to determine their individual and combined effect on NH3 emissions. Ammonia emissions varied on daily and seasonal bases with higher emissions during warmer periods. For finishers, the summertime housing emissions on a per-animal basis were 2.4 times higher than wintertime (7.0 vs. 3.3 g NH3 animal(-1) d(-1)) or 3.2 times higher when compared on an animal unit (AU) basis (1 AU = 500 kg) because of climate and animal size differences between measurement periods. For summertime, the emission factor for the finishing pigs was 7.8 times higher than for sows on an animal basis and 25.6 times higher on an AU basis. Simple models were developed for housing emissions based on (i) all measured factors that were independent of each other and (ii) on three commonly measured management factors. The two models explained 97 and 64%, respectively, of variations in emissions. Ammonia emissions were found to be somewhat less than other studies on the same type housing due to more representative housing concentration measurements and calibration of exhaust fans; thus, emission factors for these type houses will be less than previously thought.

Phosphorus (P) in irrigation runoff may enrich offsite water bodies and streams and be influenced by irrigation water quality and antecedent soil surface conditions. Runoff, soil loss, and P fractions in runoff using reverse osmosis (RO) water or mixed RO and well water (RO/ Tap) were studied in a laboratory sprinkler study to evaluate water source effects on P transport. A top- or subsoil Portneuf silt loam (coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcid), either amended or not amended with manure and/or with cheese whey, with Olsen P from 20 to 141 mg kg(-1) and lime from 108 to 243 g kg(-1), was placed in 1.5 x 1.2 x 0.2-m-deep containers with 2.4% slope and irrigated three times from a 3-m height for 15 min, applying 20 mm of water. The first irrigation was on a dry loose surface, the second on a wet surface, and the third on a dry crusted surface. Surface (ca. 2 cm) soil samples, prior to the first irrigation, were analyzed for Olsen P, water-soluble P (Pws), and iron-oxide impregnated paper-extractable P (FeO-P) analyses. Following each irrigation we determined runoff, sediment, dissolved reactive phosphorus (DRP) in a 0.45-microm filtered sample, and FeO-P and total P in unfiltered samples. Soil surface conditions had no effect on P runoff relationships. Water source had no significant effect on the relationship between DRP or FeO-P runoff and soil test P, except for DRP in RO runoff versus water-soluble soil P (r2 = 0.90). Total P in RO runoff versus soil P were not related; but weakly correlated for RO/Tap (r20.50). Water source and soil surface conditions had little or no effect on P runoff from this calcareous soil.

This paper describes a study to determine the sorption of five herbicides and three organic contaminants by five polymeric microfilters. The five filters had different membrane and housing makeups: (i) nylon-polypropylene (NY-PP), (ii) borosilicate glass-acrylic (BA-AC) (iii) polyethersulfone-acrylic (PS-AC), (iv) polyvinylidene difluoride-polypropylene (PV-PP), and (v) PTFE-polypropylene (PT-PP). The herbicides were isoxaflutole, diketonitrile, atrazine, metolachlor, and 2,4-D; the contaminants were trichloroethylene, α-naphthol, and phenanthrene. All five filters strongly sorbed the eight chemicals (except for three filters for 2,4-D) and sorption was largest at the first passage and declined with the increasing number of passages. The first passage sorption of isoxaflutole followed a decreasing order: PV-PP (92%) > BA-AC (87%) > PS-AC (42%) > PT-PP (38%) > NY-PP (26%); diketonitrile: BA-AC (69%) > PV-PP (22%) > PS-AC (18%) = NY-PP (18%) > PT-PP (12%); metolachlor: BA-AC (76%) ≥ PV-PP (75%) > PT-PP (32%) > PS-AC (23%) = NY-PP (23%); atrazine: BA-AC (78%) > NY-PP (24%) > PS-AC (19%) ≥ PT-PP (17%) ≥ PV-PP (15%); 2,4-D: NY-PP (22%) > PV-PP (7.8%) > BA-AC (1.4%) ≥ PS-AC (0.99%) ≥ PT-PP (0.41%); trichloroethylene: BA-AC (86%) >PS-AC (35%) > PV-PP (18%) ≥ NY-PP (16%) ≥ PT-PP (15%); α-naphthol: BA-AC (99%) = NY-PP (99%) > PV-PP (49%) = PS-AC (49%) > PT-PP (6.8%); and phenanthrene: PV-PP (99%) = PS-AC (99%) = NY-PP (99%) = BA-AC (99%) > PT-PP (42%). These filters are not suitable for preparing and processing environmental samples involving these eight chemicals (except for three filters for 2,4-D) unless some corrected measures are taken.

In most intensive dairy farms, P input exceeds output, causing potential P losses to the environment, which results in leaching to ground water and eutrophication. Phosphorus in fertilizer and purchased feeds are the main contributors to P input, whereas milk P is the main output. In the Netherlands, new legislation has been introduced to substantially reduce P surpluses. However, since P is essential for maintenance and milk production, the dietary P supply must be maintained, especially for high-yielding dairy cows. This paper reviews how dairy cow diets can be manipulated to reduce potential P-loss to the environment without negative effects on animal health, feed intake, or milk production. The availability of P in forages, purchased feed, and inorganic phosphate supplements for ruminants may differ substantially and more research work is needed to elucidate the relevant factors influencing feed P availability. There is a lack of understanding of how and to what extent P is absorbed from the small intestine and the relationship to hydrolysis and microbial P utilization in the rumen. Comparing national P requirement systems indicates that the systems used in the UK and Italy should be revised to minimize unnecessary P accumulation in the soil. In addition, the impact of manipulating the dietary P supply to decrease P losses from dairy farming systems is evaluated. Whole farm system studies have illustrated the potential environmental benefits of more closely monitoring imports of purchased feeds onto the farm.

The purpose of this paper is to summarize the results of a series of greenhouse and open- top chamber studies on the effects of N and elevated atmospheric CO 2 on ponderosa and loblolly pine (Pinus ponderosa Laws. and P. taeda L.) to evaluate common patterns of response. Growth response to elevated CO 2 ranged from zero to more than 1000%, depending largely upon N status. In both species, growth response to CO 2 was greater under moderate N deficiency than under extreme N deficiency or N sufficiency/excess. Elevated CO 2 generally caused lowered tissue N concentrations in many (but not all) cases, which in turn resulted in smaller increases in N uptake than in biomass. Growth response to N ranged from -50 (in ponderosa pine) to more than 1000%, depending upon the N status of the control medium. Growth response to N was enhanced by elevated CO 2 when N was in the extreme deficiency range but not when N was in the moderate deficiency range. In two separate studies, ponderosa pine responded negatively to high N inputs. and in each case this response was mitigated by elevated CO 2 . Collectively, these results show that (i) N deficiency is a continuum rather than a step function, (ii) responses to elevated CO 2 vary across this continuum of N deficiency. and (iii) elevated CO 2 greatly enhances growth response to N additions when N is initially-in the extremely deficient range.

Incineration is practiced to reduce sewage sludge volume, but disposal of the resulting ash remains an important waste-management problem. The objectives of a field study conducted from 1987 to 1990 were to evaluate sewage-sludge-incinerator ash as a P fertilizer, determine trace metal availability, and assess the liming potential of the ash. The soil was an Estherville sandy loam (sandy, mixed, mesic Typic Hapludoll) with an initial pH of 5.7. Treatments compared P rates of 35, 70, and 140 kg ha⁻¹ yr⁻¹ from triple-superphosphate fertilizer with equivalent ash rates based on citrate-soluble (available) P. A control receiving no P application was included. Field corn (Zea mays L.) was grown the first 3 yr and sweet corn was grown in 1990. Limited effects on growth occurred the first 2 yr, but in 1989 and 1990 both ash and phosphate fertilizer significantly increased yield. Yield response to ash was equivalent to phosphate fertilizer for 1989 field corn, but significantly less for sweet corn in 1990. Ash and phosphate fertilizer both increased tissue P concentrations, but phosphate fertilizer was the more effective P source. Olsen's soil P extractant provided a more useful measure of plant available P than Bray P-1 for ash-amended soil. Ash increased diethylenetriaminepentaacetic-acid (DTPA) extractable Cu, Zn, and Cd in the 0- to 15-cm soil depth and slightly buffered soil pH. Concentrations of Cu and Zn in plant tissue were consistently higher, and Mn consistently lower, with ash than with phosphate fertilizer. In 1990, ash also significantly increased tissue Cd and Mo in sweet corn. Tissue trace metal concentrations were not in the range of anticipated phytotoxicity or animal health problems. Paper no. 20915 of the Journal Series, Minnesota Agric. Exp. Stn. Research supported by the Metropolitan Waste Control Commission, St. Paul, MN.

This study was conducted to compare the mineralization of S in soils amended with various types of sewage sludges, animal manures, and plant materials. Field-moist soils amended with organic waste materials at a 50-Mg-ha⁻¹ rate were mixed with glass beads, packed in leaching columns, leached with 5 mM CaCl₂ to remove the mineral S, and incubated at 30 °C. The leaching procedure was repeated every 2 wk for 26 wk. The leachates were analyzed for SO²⁻₄-S. The rate of SO²⁻₄ release from sewage sludges was rapid during the first 6 wk, followed by a slow linear release. The release of SO²⁻₄ from anhnal manures was linear with time of incubation. With the exception of alfalfa (Medicago sativa L.), which showed a rapid SO²⁻₄ release within the first 2 wk and a subsequent linear release with time up to 26 wk, the addition of all other plant materials resulted in net S immobilization. The total net S mineralized from the organic waste materials varied considerably, depending on the type of soil and the C/N/S ratio of the organic waste material. The amounts of S mineralized in soils amended with sewage sludges and animal manures ranged from 99 to 345 mg S kg⁻¹ and from 32 to 52 mg S kg⁻¹ soil, respectively. The total S mineralized in soils amended with plant materials ranged from 15 to 57 mg S kg⁻¹. Expressed as a percentage of total organic S added to soils, the S mineralized ranged from 41 to 97% for sewage sludges and from −62 to 127% for animal manures. The percentage of organic S mineralized in the plant materials ranged from −510% for cornstalk (Zea mays L.) to 87% for alfalfa. Soil types have marked effects on the mineralizable S (S₀) pool and first-order rate constants (k). Journal Paper no. J-13691 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, IA. Projects 2112 and 2710.

The chemical stability of weekly and biweekly throughfall collection intervals were compared at two northern hardwood stands in the Great Lakes region. Throughfall concentrations of Cl⁻, NO⁻₃, SO²⁻₄, Ca²⁺, Mg²⁺, and K⁺ were not significantly (p ≤ 0.05) affected by the increased collection time, where as throughfall concentrations of NH⁺₄ and H⁺ collected biweekly were significantly different (p ≤ 0.05) than concentrations of these ions in weekly samples. The 1-wk increase in collection interval at one stand decreased concentrations of NH⁺₄ and increased concentrations of H⁺ 88 and 131%, respectively. The chemical instability of these ions appeared to be related to biological assimilation and/or nitrification of NH⁺₄. Stability of these ions decreased with increasing concentrations of inorganic N in the throughfall. These changes in concentrations of NH⁺₄ and H⁺ may introduce sampling bias when estimating throughfall fluxes or concentrations of these ions from biweekly collections. The decreased stability of these ions with increased concentrations of inorganic N should be an important consideration when selecting sampling intervals for stands that receive differing deposition levels of atmospheric N or have different canopy retention rates of N. This study was supported by funds provided by the Quality Assurance Coop. and the Eastern Hardwood Res. Coop. within the joint USEPA/USDA-FS Forest Response Program. This paper has not been subject to USEPA, USDA-FS peer review and should not be construed to represent the policies of these agencies.

Feeding trials were conducted with rats (Rattus rattus) to examine effects of soil application, or dietary inclusion, of fluidized bed combustion residue (FBCR) on the composition and quality of foods. Four diets (vegetable protein, egg protein, chicken, chicken + dietary FBCR) prepared with either FBCR or lime (control) treatments, were fed to weanling, female rats in three growth and reproduction trials. Intake, growth rate, and composition of body and organs of rats were measured. Rats in one trial were bred, their litters maintained on dietary treatments, and the offspring rebred. Treatment (FBCR vs. lime) × diet interactions on food composition and animal responses generally were not significant. Treatment had little effect on element composition of diets; mineral concentrations were in normal ranges. Diet treatment with FBCR depressed (P < 0.01) food intake and growth of rats in one trial, but not in others, and had no effect (P < 0.05) on body water, protein, ether extract, or gross energy composition. Some differences in element concentrations in the carcass and organs of rats and pups resulted from FBCR treatment, but effects were small and inconsistent. Litters from the first reproductive cycle appeared normal, except for animals fed the chicken + dietary FBCR treatment, on which pups showed poor growth and anemia. Offspring from certain diets were rebred and litters showed a high mortality, although this was not associated specifically with FBCR treatment. Results indicated no major detrimental effects on food composition, or growth, tissue element accumulation, and reproduction in the rat relating to use of FBCR as a soil amendment. Scientific Paper no. 2079 of the West Virginia Agric. and For. Exp. Stn., Morgantown, WV.

Excessive applications of poultry (chicken, Gallus gallus domesticus) manure in some cropping systems have resulted in nitrate contamination of groundwater. To determine the application rates necessary for optimum crop growth and minimal nitrate leaching, estimates of the availability of N in poultry manure are necessary. This research investigated, under laboratory and field conditions, an approach that could be used to predict available N in poultry manure. In the laboratory study, 20 manures were incorporated with a Kalmia sandy loam (Typic Hapludults) at rates estimated to provide 100 mg predicted available N (PAN) kg⁻¹ soil, where PAN = 80% Nᵢ + 60% Nₒ and Nᵢ = (NH₄-N + NO₃-N), Nₒ = (Total N − Nᵢ). Actual available N, defined as Nᵢ initially extractable by 2 M KCl, plus N mineralized during a 140-d nonleached incubation study, ranged from 54 to 118 mg N kg⁻¹ soil. A field study was also conducted at two locations comparing three poultry manures, applied at rates of 0, 90, 180, and 270 kg PAN ha⁻¹, with ammonium nitrate (AN) applied at the same rates. Irrigated corn (Zea mays L.) was grown at both sites during 1985 and soil, plant, and yield data were obtained. Nitrogen content of ear leaf samples at mid-silking was significantly less, at both sites, for the three manures than for AN. No significant differences in grain yields were observed between N sources at site one, but average yields (across N rate) were significantly less with two of the poultry manures (PM-7, PM-11), relative to AN, at site two. Postharvest soil samples (0–100 cm) were obtained from the control (0N) and 270 kg PAN ha⁻¹ rates of all N sources. Residual Nᵢ was less than 10 mg kg₋₁ for all treatments and depths; however, significantly higher (P = 0.08) NO₃-N levels were found with AN at the 60 to 80 depth cm at site two and at the 80 to 100 cm (P < 0.05) depths at sites one and two. The field study was repeated at the same sites in 1986 to assess the residual N value of manure applied in 1985. Based on ear leaf N and grain yields, residual available N from manures was determined to be less than 45 kg N ha⁻¹. The second year decay constant for PM was estimated, by comparison with AN yields, to be 0.11 and 0.06 at sites one and two, respectively. Published by the Delaware Agric. Exp. Stn. as Misc. Paper no. 1171. Contribution no. 983 of the Dep. of Plant Sci., Univ. of Delaware, Newark, DE.