Jeffery C. Lorimor

Vegetative Treatment Systems for Management of Open Lot Runoff: Review of Literature

Runoff from open lot livestock systems (beef and dairy) defined as Concentrated Animal Feeding Operations (CAFO) must be controlled by systems designed and managed to prevent the release of manure-contaminated runoff for storms equal to or less than a 25-yr, 24-h design storm. This performance standard has been attained for open lot systems with some combination of clean water diversion, settling basins, runoff collection ponds, and irrigation systems (baseline system). An alternative approach is to rely on overland flow and infiltration into cropland with perennial forage or grasses for treatment of open lot runoff. Such vegetative systems have been researched since the late 1960s. This article reviews the research literature on vegetative treatment systems (VTS) for managing open lot runoff summarizing available science on system performance, design, and management. Based upon this review of the literature, the following conclusions are drawn about the application of VTS to manage runoff from open lot livestock production systems: (1) Substantial research (approximately 40 identified field trials and plot studies) provides a basis for understanding the performance of VTS. These performance results suggest that a vegetative system consisting of a settling basin and VTA or Vegetative Infiltration Basin (VIB) has the potential to achieve functional equivalency to conventional technologies. (2) The existing research targeting VTS is confined to non-CAFO applications, likely due to past regulatory limits. Unique challenges exist in adapting these results and recommendations to CAFO applications. (3) The pollutant reduction resulting from a VTS is based upon two primary mechanisms: 1) sedimentation, typically occurring within the first few meters of a VTS, and 2) infiltration of runoff into the soil profile. Systems relying primarily on sedimentation only are unlikely to perform equal to or better than baseline technologies. System design based upon sedimentation and infiltration is necessary to achieve a required performance level for CAFO application. (4) Critical design factors specific to attaining high levels of pollutant reduction within a VTS include pre-treatment, sheet flow, discharge control, siting, and sizing. Critical management factors include maintenance of a dense vegetation stand and sheet flow of runoff across VTA as well as minimization of nutrient accumulation.

NEAR-INFRARED SENSING OF MANURE NUTRIENTS

The effectiveness of near-infrared (NIR) technology for quickly analyzing the nutrient content of three types of animal manure was evaluated. Swine lagoon effluent, liquid swine pit manure, and solid beef feedlot manure were tested. An NIRSystems 6500 scanning monochromator unit was calibrated against wet chemistry data. Total solids (TS), total Kjeldahl nitrogen (TKN), ammonia nitrogen (NH3-N), total phosphorus (P), and potassium (K) were measured. Correlation coefficients (r) ranged from 0.688 to 0.976, Ratios of data range:standard error of prediction (SEP) varied from 7.0 to 13.6 for the various chemical constituents and manure sources. Based on the individual ratios we conclude that NIR techniques will allow us to predict TS, TKN, NH3-N, and K in all three manure types. Further work will be required before P is predictable.

Manure Incorporation Equipment Effects on Odor, Residue Cover, and Crop Yield

Land application of manure may produce unacceptable odors. Field experiments in undisturbed (no-till) soybean and corn residue were conducted to evaluate six liquid swine manure application/incorporation methods. The methods were injection with a commercial (1) chisel or (2) sweep, (3) incorporation with tandem disk harrow after broadcast application, (4) broadcast application with no incorporation, (5) injection with a narrow-profile knife, and (6) surface application behind row cleaners. The row cleaner and all injection treatments used spoke-covering wheels. Air samples over the soil surface were obtained immediately following and one day after manure application, and odor level was measured by olfactometry (i.e., the amount of air dilutions to reach odor threshold). Residue cover and yield were also measured. Incorporation techniques typically reduced odor level by a factor of three to ten as compared with a broadcast application. One day after application, odor was greatly reduced and often indistinguishable from that of untreated soil (no manure application). Residue cover differences among application methods were more pronounced in soybean residue. Application by the narrow-profile knife, row cleaner, and chisel maintained soybean residue cover better than other incorporation methods yet limited odor similar to these methods. Although cover was reduced over winter, greater soybean residue cover remained after planting with fall than with spring manure applications. Differences in odor level and residue cover among methods were less in corn than soybean residue. All incorporation techniques reduced odor levels, and chisel incorporation maintained corn residue cover after planting similar to broadcast application. For both crops, broadcast application maintained the greatest residue cover but had the highest odor level. Incorporation of manure generally reduced odor, reduced residue cover, increased corn yield, and did not affect soybean yield.

Nitrogen Losses from Laying Hen Manure in Commercial High-rise Layer Facilities

Nitrogen (N) losses from four high-rise laying hen houses, representing four commercial layer farms in Iowa, were determined from measured performance data of Hy-Line W-36 White Leghorn layers (i.e., manure production, egg production, feed intake, body weight, and mortality). Nitrogen loss was 25, 33, 37, and 41% for Farms A, B, C, and D, respectively, based on the Total Kjeldahl Nitrogen (TKN) in feed. A significant factor contributing to the difference in the N losses was the moisture content (MC, percent on an as-is basis) in manure stored in the ventilated manure storage area of the layer houses. The higher the MC, the higher the ratio of NH 3 /TKN Manure in the stored manure, and therefore, the higher the percentage of N loss. Mathematical relationships were developed. Manure handling systems played an important role in N loss by influencing MC of the manure which, in turn, affects rate of manure decomposition. Understanding the factors affecting decomposition and N loss mechanisms of layer manure could provide a means to significantly reduce ammonia emissions to the atmosphere from poultry facilities.

Fecal Indicator Bacteria in Subsurface Drain Water Following Swine Manure Application

Appropriate manure application parameters are necessary to maximize nutrient utilization by plants from manure while minimizing water pollution potential. This study focused on the movement of bacteria to receiving tile drains following swine manure application. Specifically, the impacts of different manure application regimes on fecal coliform (FC), Enterococcus (EN), and Escherichia coli (EC) densities in subsurface tile drain water were examined for three years. Manure treatments, including fall, spring, and late winter application at a recommended rate of 168 kg N ha-1 (1X) and at 336 kg N ha-1 (2X) were compared with a non-manure treatment where commercial urea-ammonium nitrate (UAN) was applied. Results indicate that flow-weighted average and maximum observed EN and EC levels in tile water were significantly higher where manure had been applied during late winter at the 2X rate versus the UAN and fall treatments. Levels of FC were highly variable, and the spring injection 1X treatment yielded the highest flow-weighted average and maximum tile water FC levels. Results of this study suggest that manure broadcast onto frozen ground may lead to significantly elevated EN and EC levels in tile water in similar environments, especially when applied in excess of crop nutrient requirements.

Effects of Laying Hen Manure Application Rate on Water Quality

Excessive use of animal manure on agricultural lands can impact the quality of surface and groundwater resources. A three–year study (1998–2000) was conducted on nine 0.4–ha plots and on six 2.1–m 2 lysimeters to investigate the effect of two nitrogen (N) application rates from laying hen manure and one N application rate from urea ammonium nitrate (UAN) fertilizer on surface and groundwater quality. Experimental treatments included N application rates of 168 kg–N/ha from UAN fertilizer, and 168 kg–N/ha and 336 kg–N/ha from laying hen manure to corn plots. Subsurface drain and runoff water samples were collected and analyzed for nitrate–nitrogen (NO3–N) and orthophosphate (PO4–P). Results of this study indicate that application of hen manure at 336 kg–N/ha resulted in the highest average NO3–N and PO4–P concentrations in subsurface drain water in comparison with the application of 168 kg–N/hafrom either hen manure or UAN fertilizer. Application of manure at 168 kg–N/ha resulted in significantly lower NO3–N loss with subsurface drain water in comparison with NO3–N loss from the other two N treatments. Manure application at a rate of 336 kg–N/ha resulted in a higher concentration of PO4–P in surface runoff in comparison with manure application rate of 168 kg–N/ha. Application rate of manure had no significant effect on NO3–N concentration in surface runoff water. In addition, higher PO4–P losses were observed with surface runoff water in comparison with subsurface drain water. The use of manure at both low and high application rates in field plots resulted in significantly higher corn and soybean yields in comparison with the use of UAN fertilizer. Results of this study led to the conclusions that application of hen manure at a lower rate of 168 kg–N/ha can result in higher crop yields and minimal water pollution in comparison with same amount of UAN fertilizer or higher manure application rate.

Indicator Bacteria in Subsurface Drain Water Following Swine Manure Application

Appropriate manure application rates, timing, and methods are necessary to maximize nutrient utilization by plants from manure, while minimizing water resource pollution potential, including that of enteric organisms. A field study and a soil column study examined the response of indicator bacterial densities in subsurface drain water to different swine manure applications. The field study focused on the impacts of different manure management regimes on fecal coliform, fecal streptococcus, and Escherichia coli (E. coli) densities in subsurface tile drain water. Eight swine manure treatments were compared with a control treatment where commercial urea ammonium nitrate was applied. Manure treatments included fall injection, spring injection, and late winter broadcast at application rates of 168 kg N/ha and 336 kg N/ha. Results indicated that the highest incidence of significantly elevated bacterial levels occurred where manure had been broadcast in late winter at a rate of 336 kg N/ha.

Application of Near-Infrared Reflectance Spectroscopy for Determination of Nutrient Contents in Liquid and Solid Manures

Proper application of livestock manure to agricultural land converts waste to fertilizer, but relies on knowing the nutrient content of the manure. Manure samples (111 solid poultry layer, 95 solid poultry broiler litter, 39 swine solid hoop, 72 beef cattle, 85 swine slurry, and 88 swine liquid lagoon) were collected from farms in three states to investigate the feasibility and limitations for using near-infrared reflectance spectroscopy (NIRS) to analyze manure nutrients. Spectral data in the near-infrared (NIR) region (1100-2500 nm) from manure samples were correlated with chemical analytical data from the same samples using partial least squares regression techniques in conjunction with six mathematical data pretreatments. The best calibration equations were selected on the basis of the smallest standard error of prediction (SEP) and the largest coefficient of determination (R 2 ) of cross-validation. The ratio (abbreviated as RPD) of the standard deviation (SD) of the constituent in the sample population to the SEP was used to evaluate the future prediction performance of calibration models. After using the mathematical pretreatments, the R 2 values of the one-out cross-validation for total solids (TS), volatile solid (VS), total nitrogen (TN), and ammonia nitrogen (NH3-N) were between 0.80 and 0.97 for all manure samples. The R 2 values of the one-out cross-validation for minerals ranged from 0.71 to 0.81, 0.50 to 0.78, 0.74 to 0.94, 0.66 to 0.91, 0.73 to 0.91, and 0.70 to 0.90 in poultry solid layer, poultry broiler litter, swine solid hoop, beef cattle, swine liquid lagoon, and swine slurry manure samples, respectively. The RPD values indicate that NIRS can predict TS, VS, TN, NH3-N, and some minerals in manures. NIRS has potential to predict some nutrient concentrations in manure rapidly and accurately.

Manure Production and Nutrient Concentrations from High-rise Layer Houses

Four commercial high-rise layer houses were monitored for a year to determine manure production and nutrient concentration characteristics. Each house contained 80,400 to 124,500 mature Hy-Line W-36 birds. The solid manure collected as it accumulated beneath the cages for a year prior to being hauled out. The objective of the research was to accurately characterize the manure production to facilitate better nutrient planning. Manure volume and bulk density were measured and samples were collected monthly and analyzed for moisture, Kjeldahl nitrogen, ammonia, phosphorus, potassium, calcium, and other chemical constituents. The measured manure production averaged 5.6 Mg (or 6.2 ton)·(1000 birds) –1 (year –1 on a dry basis. On a wet (as-is) basis the measured production was 9.52 Mg (or 10.5 ton)·(1000 birds) –1 (year –1 at 41% moisture. The measured manure N-P 2 O 5 -K 2 O contents were 18.5-41.0- 26.0 kg/Mg (37-82-52 lb/ton) on an “as-is” basis or 30.8-69.0-44.0 kg/Mg (62-138-88 lb/ton) on a dry basis. When manure production and nutrient concentrations were combined, measured nitrogen production was 52.8% less, phosphorus was 29.5% greater, and potassium was 27.8% greater, than the respective current Iowa estimates. The average calcium concentration for all four sites studied for the year was 10.0% (as-is basis). The manure handling system had a significant impact on manure characteristics. Scraper systems had a lower moisture content and a lower percentage of the nitrogen in ammonia form (29.8% moisture, NH 3 = 20% of TKN) than systems that dropped the manure into storage immediately (46.9% moisture, NH 3 = 30% TKN).

SOIL INFILTRATION AND WETLAND MICROCOSM TREATMENT OF LIQUID SWINE MANURE

Management systems are needed to minimize water quality concerns associated with liquid swine manure from large swine production facilities. Experiments were conducted to investigate the removal of ammonium–N, nitrate–N, and total phosphorus from liquid swine manure through the use of a soil infiltration and wetland system. Experimental treatments applied directly to the soil infiltration areas included a full–rate application of liquid swine manure, a mixture of 3/4 manure and 1/4 water, and a control application of water only. For three months during both summers of 1998 and 1999, nutrient concentrations were determined in the infiltration area influent, the infiltration area effluent, and the wetland effluent on a weekly basis. Approximately 93% of the ammoniacal nitrogen (NH3–N and NH4–N) from the applied swine manure was removed by the soil infiltration areas with a corresponding 99% increase in the nitrate nitrogen (NO3–N) concentrations were found. The wetland systems removed 94% of the remaining NH3–N and NH4–N and 95% of the NO3–N. The total P levels were decreased in the soil infiltration areas and wetlands by 89 and 84%, respectively.