Hydrologic modeling of runoff from a livestock manure windrow composting site with a fly ash pad surface and vegetative filter strip buffers

Windrow composting of livestock manure materials provides a strategy for converting organic wastes into a recyclable soil fertility product that is less hazardous to the environment. Although outdoor windrow composting can produce runoff that is detrimental to surface water quality, vegetative filter strip (VFS) buffers were reported to significantly reduce runoff and contaminants from a windrow composting research site. To estimate the efficacy of VFS buffers and other best management practices on runoff from future windrow composting facilities, a computer hydrologic model may provide a valuable tool for predicting runoff losses from these proposed sites. This research evaluated a windrow composting/vegetative filter strip buffer (WCVFS) hydrologic model for estimating runoff volume losses from a livestock manure-based windrow composting site with a fly ash composting pad surface and VFS buffers. Runoff and physical attribute data from six rainfall events during 2002 to 2004 at a central Iowa windrow composting research site were used in the WCVFS model evaluation. Three rainfall events were designated as “wet” composting period events (2002 and 2003 seasons), and three were designated as “dry” composting period events (2004 season). Runoff data were comprised of average observed runoff volumes from three compost windrow area:VFS buffer area ratio treatments that included 1:1, 1:0.5 (large and small VFS buffer areas, respectively), and a 1:0 (no buffer) control. The WCVFS model performance was good to very good for the 2003 wet composting period model validation rainfall event with no significant differences among 1:1, 1:0.5, and 1:0 ratio treatments for simulated versus observed runoff volumes. In contrast, WCVFS model performance was unsatisfactory for the 2004 dry composting period validation event with significantly higher simulated runoff volume from the 1:0.5 ratio treatment versus observed runoff volumes. There were no significant differences for the 1:1 and 1:0 treatments. The WCVFS model effectively estimated 1:1, 1:0.5, and 1:0 treatment runoff volumes from the earlier wet composting period and 1:1 and 1:0 treatment runoff volumes from the later dry composting period rainfall events. However, the soils data-derived VFS buffer runoff and infiltration functions in the WCVFS model flow routing component may not have sufficiently accounted for some short-term hydrologic changes in VFS buffer soil and fly ash pad surfaces. This could have resulted in overestimation of dry composting period simulated runoff volume from the smaller 1:0.5 ratio VFS buffer area treatment. Consequently, the use of other alternatives to soils data-derived VFS buffer runoff and infiltration functions should be evaluated in future WCVFS model simulation trials to potentially improve runoff volume prediction accuracy

Livestock Manure Windrow Composting Runoff And Infiltration Characteristics from Laboratory Rainfall Simulations

Windrow-composted livestock manure has been shown to be less hazardous to the environment compared to manure directly applied to cropland and other agricultural areas. Although offsite contaminant losses through runoff and leaching can occur during the composting process, these losses are suspected to increase under different compost moisture conditions and as composted materials mature. This research quantified the effects of windrow-composted livestock manure and straw bedding components on runoff and infiltration characteristics from laboratory rainfall simulations. Compost samples collected on three dates at approximately the beginning (day 0), middle (day 30), and end (day 60) of a June-July 2004 field research windrow composting period were used for this rainfall simulation study. Replicated compost windrow-shaped cross-section samples were constructed in a specially-designed Plexiglas container apparatus for viewing and recording infiltrated leachate wetting front position boundary movement from simulated rainfall events. Runoff and leachate samples were collected and analyzed for drainage volumes and concentrations and total mass losses of sediment, nitrate-nitrogen (NO3-N), and ortho-phosphorus (PO4-P) during and following rainfall simulation trials. Leachate wetting front position boundary movement was significantly lower for day 60 compost samples compared among day 0 and day 30 compost sample material. Drainage volume analysis results indicated significantly higher average runoff versus leachate volumes within all compost sampling dates, and runoff volumes were significantly higher among day 30 and day 60 compost samples compared to runoff volumes from day 0 compost samples. Average sediment, NO3-N, and PO4-P concentrations were significantly higher in leachate versus runoff within all compost sampling dates. Conversely, the total mass losses of these contaminants were significantly higher in runoff compared to leachate within all compost sampling dates. Results of this study suggest that biological and mechanical functions of the composting process reduced compost sample aggregates and increased compost bulk density. We hypothesize that these changes in compost material structure and porosity volume decreased infiltration and increased runoff sediment, NO3-N, and PO4-P losses during the second and final compost sampling stages of a field windrow composting period

Pair distribution function and structure factor of spherical particles

The availability of neutron spallation-source instruments that provide total scattering powder diffraction has led to an increased application of real-space structure analysis using the pair distribution function. Currently, the analytical treatment of finite size effects within pair distribution refinement procedures is limited. To that end, an envelope function is derived which transforms the pair distribution function of an infinite solid into that of a spherical particle with the same crystal structure. Distributions of particle sizes are then considered, and the associated envelope function is used to predict the particle size distribution of an experimental sample of gold nanoparticles from its pair distribution function alone. Finally, complementing the wealth of existing diffraction analysis, the peak broadening for the structure factor of spherical particles, expressed as a convolution derived from the envelope functions, is calculated exactly for all particle size distributions considered, and peak maxima, offsets, and asymmetries are discussed.Comment: 7 pages, 6 figure

Swine Manure Rate, Timing, and Application Method Effects on Post-Harvest Soil Nutrients, Crop Yield, and Water Quality Implications in a Corn-Soybean Rotation

This report documents results from a six-year study (1996-2001) that evaluated effects of liquid swine manure application management practices on soil nutrients, organic matter, pH, crop yield; and also discussed water quality implications. Swine manure management practices included single-rate (SR) and double-rate (DR) nitrogen (N)-based application rates (168 and 336 kg N ha-1, respectively), three timings (fall injection [FI], winter broadcast [WB], and spring injection [SI]), and two methods (broadcast and injection) of liquid swine manure. Analysis of these practices involved comparing levels of residual soil total phosphorus (P) as Bray-1 available P (RSP), residual soil nitrate-N (RSN), percent organic matter (OM%), pH, carbon:nitrogen (C:N) ratio, and crop yields (kg ha-1) in a corn-soybean rotation. Results of this study indicated that long-term application of higher liquid swine manure rates during winter and spring application times resulted in significantly higher post-harvest accumulation of RSN and RSP in the soil profile, with no significant changes in soil OM%, pH, and C:N ratio. These results also showed that incorporation of swine manure during the spring application time produced significantly higher corn yields compared with fall and winter application times. Overall results suggest that while RSN and RSP content may be significantly higher from spring versus fall manure application times, N and P runoff losses and the potential threat to surface water quality may be substantially lower during spring and summer compared with fall and winter due to effects from crop nutrient uptake, microbial activity, leaching, and evapotranspiration during the growing season

ADVISORY SERVICE MARKETING PROFILES FOR CORN OVER 1995-2000

This report presents marketing profiles and loan deficiency payment/marketing loan gain profiles for the advisory services followed by the AgMAS Project for the 1995 through 2000 corn crops. Marketing profiles are constructed by plotting the cumulative net amount priced under each program's set of recommendations throughout a crop year. Loan deficiency payment/marketing loan gain (LDP/MLG) profiles are constructed by plotting the cumulative percentage of the crop on which the LDP/MLG was claimed during the crop year. Marketing profiles provide information to evaluate the style of advisory services in several ways. The percentage of crop priced is a measure of within-crop year price risk. The higher the proportion of a crop priced, the lower the sensitivity of the farmer's position value to crop price changes. For example, when 100% of the crop is priced there is no price sensitivity, which means that changes in price do not affect the value of the farmer's position. On the other hand, when the amount priced is 0%, the value of the farmer's position will vary in the same proportion as the change in price. Marketing profiles, therefore, allow investigating the evolution of price sensitivity under each service's set of recommendations along the marketing window. Marketing profiles also provide other useful information. The number of steps in the profile lines and the location of these steps in the marketing window provide information about timing, frequency and size of recommended transactions. It is also possible to determine from the marketing profile figures how intensely a program uses options markets, since when options positions are open the profile line is irregular. In the same way, LDP/MLG profiles provide information about the size and timing of LDP/MLG claims.Marketing,

ADVISORY SERVICE MARKETING PROFILES FOR SOYBEANS OVER 1995-2000

This report presents marketing profiles and loan deficiency payment/marketing loan gain profiles for the advisory services followed by the AgMAS Project for the 1995 through 2000 soybean crops. Marketing profiles are constructed by plotting the cumulative net amount priced under each program's set of recommendations throughout a crop year. Loan deficiency payment/marketing loan gain (LDP/MLG) profiles are constructed by plotting the cumulative percentage of the crop on which the LDP/MLG was claimed during the crop year. Marketing profiles provide information to evaluate the style of advisory services in several ways. The percentage of crop priced is a measure of within-crop year price risk. The higher the proportion of a crop priced, the lower the sensitivity of the farmer's position value to crop price changes. For example, when 100% of the crop is priced there is no price sensitivity, which means that changes in price do not affect the value of the farmer's position. On the other hand, when the amount priced is 0%, the value of the farmer's position will vary in the same proportion as the change in price. Marketing profiles, therefore, allow investigating the evolution of price sensitivity under each service's set of recommendations along the marketing window. Marketing profiles also provide other useful information. The number of steps in the profile lines and the location of these steps in the marketing window provide information about timing, frequency and size of recommended transactions. It is also possible to determine from the marketing profile figures how intensely a program uses options markets, since when options positions are open the profile line is irregular. In the same way, LDP/MLG profiles provide information about the size and timing of LDP/MLG claims.Marketing,

Kidney after nonrenal transplantation-the impact of alemtuzumab induction

BACKGROUND.: Calcineurin inhibitor nephrotoxicity in nonrenal allograft recipients can lead to end-stage renal disease and the need for kidney transplantation. We sought to evaluate the role of alemtuzumab induction in this population. PATIENTS AND METHODS.: We evaluated 144 patients undergoing kidney transplantation after nonrenal transplantation between May 18, 1998, and October 8, 2007. Seventy-two patients transplanted between January 15, 2003, and October 8, 2007, received alemtuzumab induction and continued their pretransplant immunosuppression. Seventy-two patients transplanted between May 18, 1998, and July 21, 2007, did not receive alemtuzumab induction, but received additional steroids and maintenance immunosuppression. Donor and recipient demographics were comparable. RESULTS.: Overall, 1-and 3-year patient survival and renal function were comparable between the two groups. One-and 3-year graft survival was 93.0% and 75.3% in the alemtuzumab group and 83.3% and 68.7% in the no alemtuzumab group, respectively (P=0.051). The incidence of acute rejection was lower in the alemtuzumab group, 15.3%, than in the no alemtuzumab group, 41.7% (P=0.0001). The incidence of delayed graft function was lower in the alemtuzumab group, 9.7%, than in the no alemtuzumab group, 25.0% (P=0.003). The incidence of viral complications was comparable. CONCLUSION.: Alemtuzumab induction with simple resumption of baseline immunosuppression in patients undergoing kidney transplantation after nonrenal transplantation represents a reasonable immunosuppressive strategy. Copyright © 2009 by Lippincott Williams & Wilkins

Livestock grazing and vegetative filter strip buffer effects on runoff sediment, nitrate, and phosphorus losses

Livestock grazing in the Midwestern United States can result in significant levels of runoff sediment and nutrient losses to surface water resources. Some of these contaminants can increase stream eutrophication and are suspected of contributing to hypoxic conditions in the Gulf of Mexico. This research quantified effects of livestock grazing management practices and vegetative filter strip buffers on runoff depth and mass losses of total solids, nitrate-nitrogen (NO3-N), and ortho-phosphorus (PO4-P) under natural hydrologic conditions. Runoff data were collected from 12 rainfall events during 2001 to 2003 at an Iowa State University research farm in central Iowa, United States. Three vegetative buffers (paddock area:vegetative buffer area ratios of 1:0.2, 1:0.1, and 1:0 no buffer [control]) and three grazing management practices (continuous, rotational, and no grazing [control]) comprised nine treatment combinations (vegetative buffer ratio/grazing management practice) replicated in three 1.35 ha (3.34 ac) plot areas. The total 4.05 ha (10.02 ac) study area also included nine 0.4 ha (1.0 ac) paddocks and 27 vegetative buffer runoff collection units distributed in a randomized complete block design. The study site was established on uneven terrain with a maximum of 15% slopes and consisted of approximately 100% cool-season smooth bromegrass. Average paddock and vegetative buffer plant tiller densities estimated during the 2003 project season were approximately 62 million and 93 million tillers ha−1 (153 million and 230 million tillers ac−1), respectively. Runoff sample collection pipe leakage discovered and corrected during 2001 possibly reduced runoff depth and affected runoff contaminant mass losses data values. Consequently, 2001 runoff analysis results were limited to treatment comparisons within the 2001 season and were not compared with 2002 and 2003 data. Analysis results from 2001 showed no significant differences in average losses of runoff, total solids, NO3-N, and PO4-P among the nine vegetative buffer/grazing practice treatment combinations. Results from 2002 indicated significantly higher losses of runoff and total solids from 1:0 no buffer/rotational grazing and 1:0 no buffer/continuous grazing treatment combination plots, respectively, compared among other 2002 season treatment combinations. The 2003 results showed significantly higher runoff and total solids losses from 1:0 no buffer/no grazing treatment combination plots compared among all 2003 treatment combinations and from 1:0.1 vegetative buffer/no grazing treatment combination plots compared among all 2003 treatment combinations and with respective 2002 treatment combinations. However, the 2003 results indicated effective vegetative buffer performance with significantly lower runoff, total solids, and NO3-N losses from the larger 1:0.2 buffer area compared among the smaller 1:0.1 buffer area and 1:0 no buffer treatment combinations. The 2003 results also indicated a highly significant increase in losses of NO3-N from 1:0.1 buffer/no grazing treatment combination plots compared among other 2003 season treatment combinations and with respective 2002 treatment combinations. Overall results from this study suggest a shift from significantly higher 2002 season plot losses of continuous and rotational grazing treatment combinations to significantly higher 2003 season losses of no grazing treatment combinations. We speculate this shift to significantly higher runoff and contaminant losses from no grazing treatment combination plots during 2003 reflects the variability inherent to a complex and dynamic soil-water environment of livestock grazing areas. However, we also hypothesize the environmental conditions that largely consisted of a dense perennial cool-season grass type, high-relief landscape, and relatively high total rainfall depth may not necessarily include livestock grazing activities

Vegetative Buffer and Fly Ash Pad Surface Material System Application for Reducing Runoff, Sediment and Nutrient Losses from Livestock Manure Windrow Composting Facilities

Applying livestock manures to agricultural cropland continues to contribute significant levels of sediment and nutrient pollutants to streams and other water bodies. Vegetative buffers have been extensively demonstrated to reduce surface runoff flow, sediment, and nutrient losses. The coal-fired combustion by-product fly ash also has been shown to exhibit significant water-absorption and phosphorus-sorbing properties. This study investigated a vegetative buffer and fly ash pad surface material system for reducing runoff flow and water quality effects from a livestock manure windrow composting facility. Surface runoff, runoff percent of rainfall, total solids, nitrate-nitrogen, ortho-phosphorus, and total phosphorus were researched during 2002-2004 at a central Iowa dairy cow manure windrow composting research facility. Three compost windrow: vegetative buffer area ratios comprised the surface runoff treatments that included 1:1, 1:0.5, and 1:0 (no buffer control) area ratios, respectively. The 1:1 and 1:0.5 area ratios represented a 6.0 m-wide x 23 m-long fly ash composting pad area compared to vegetative buffer areas of equal and one-half size, respectively, with three replications of each treatment for a total of nine runoff plots in a randomized complete block design. Results from this study showed significantly high levels of runoff flow, sediment, and nutrients from the 1:0 control plots compared to the 1:1 and 1:0.5 vegetative buffer plots. The 1:1 and 1:0.5 vegetative buffer treatments were not significantly different and average runoff loss reductions from the 1:1 and 1:0.5 vegetative buffer plots were 98% and 93%, respectively, when compared to the 1:0 control plots. These findings underscore the efficacy of vegetative buffers in reducing surface runoff flow, sediment, and nutrient losses from a livestock manure windrow composting operation. Mass balance analysis results also indicated 41% and 26% of ortho-phosphorus were lost from the compost windrows during the 2004 early season and late season composting periods, respectively. However, only 0.1% and 0.4% of ortho-phosphorus were lost to runoff from the 1:0 control plots during the respective 2004 early season and late season composting periods. These results indicate the significantly lower ortho-phosphorus losses in runoff are attributed to the inherent chemical and physical phosphorus-sorption characteristics of the fly ash composting pad surface material. This vegetative buffer and fly ash pad surface material system application can significantly reduce surface runoff flow, sediment, and nutrient losses from a livestock manure windrow composting facility