The placement of stiff-stemmed grass hedges on the contour along a hillslope has been shown to decrease nutrient transport in runoff. This study was conducted to measure the effectiveness of a narrow grass hedge in reducing runoff nutrient transport from plots with a range of soil nutrient values. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha(-1) to a silty clay loam soil and then incorporated by disking. Soil samples were collected 243 days later for analysis of water-soluble phosphorus (WSP), Bray and Kurtz No. 1 phosphorus (Bray-1 P), NO3-N, and NH4-N. Three 30 min simulated rainfall events, separated by 24 h intervals, were then applied. The transport of dissolved phosphorus (DP), total P (TP), NO3-N, NH4-N, total nitrogen (TN), runoff, and soil erosion were measured from 0.75 m wide x 4.0 m long plots. Compost application rate significantly affected soil measurements of WSP, Bray-1 P, and NO3-N content. The transport of DP, TP, NO3-N, NH4-N, TN, runoff, and soil erosion was reduced significantly on the plots with a grass hedge. Mean runoff rates on the hedge and no-hedge treatments were 17 and 29 mm, and erosion rates were 0.12 and 1.46 Mg ha(-1), respectively. Compost application rate significantly affected the transport of DP, TP, and NO3-N in runoff. The experimental results indicate that stiff-stemmed grass hedges, planted at selected downslope intervals, can significantly reduce the transport of nutrients in runoff from areas with a range of soil nutrient values.

Adsorption and desorption of phosphorus (P) and nitrogen (N) by stalk residues may influence the concentrations of P and N in runoff. A laboratory study was conducted to measure the effects of P and N constituents in solution on adsorption and desorption of P and N by corn, soybean, and wheat stalk residues. Experimental variables included type of stalk material (corn, soybean, and wheat), inorganic nutrients in solution (PO(4)-P and NO(3)-N; PO(4)-P and NH(4)-N; NO(3)-N and NH(4)-N; and PO(4)-P, NO(3)-N, and NH(4)-N), solution concentration (0, 6, 12, and 24 mu g g(-1) residue), and stalk immersion period (25, 250, 2500, 25000, and 86400 s). The initial concentration of each of the P and N constituents in a particular test solution was the same (0, 6, 12 or 24 mu g mL(-1)). Corti-stalk residues released PO(4)-P, NO(3)-N, and NH(4)-N. The quantity of PO(4)-P released generally increased as the length of time the corn stalks were immersed became greater. The presence of P and N constituents in solution in general did not affect the quantity of NO(3)-N released by corn-stalk residues. Soybean-stalk residues released PO(4)-P and adsorbed relatively small amounts of NH(4)-N. Wheat-stalk residues released PO(4)-P and adsorbed NO(3)-N and NH(4)-N. The presence of stalk residues, P or N solution concentration, and residue immersion period may influence P and N concentrations of overland flow. The amount of P and N adsorbed or desorbed by residue materials can be significantly different if more than one nutrient constituent is present in solution.

Little information is currently available concerning the effects of varying flow rate on nutrient transport by overland flow. The objective of this study was to measure the effects of overland flow rate on nutrient transport following the application of beef cattle or swine manure to plots containing 0, 2, 4, or 8 Mg ha(-1) of corn residue. After addition of residue materials to 0.75 in wide by 2.0 in long plots, beef cattle or swine manure was added and the plots were then either disked or maintained in a no-till condition. Three 30 min simulated rainfall events, separated by 24 h intervals, were applied at an intensity of approximately 70 mm h(-1). The transport of dissolved phosphorus (L)P), particulate P (PP), total phosphorus (TP), NO3-N, NH4-N, total nitrogen (TN), and soil loss was measured. Nutrient load from the plots on which manure was applied was not significantly affected by the amount of corn residue on the soil surface. Transport of DP in runoff was greater under no-till than till conditions. Rate of overland flow significantly affected PP and TP load. The transport of NO3-N and TN was affected by runoff rate but was not significantly influenced by tillage. Both tillage and runoff rate were found to affect the transport of NH4-N in runoff. Soil loss was significantly influenced by the amount of residue on the soil surface and runoff rate. Tillage condition and runoff rate should be considered when nutrient transport from land application areas is estimated.

Manure is applied to cropland areas managed under diverse conditions, resulting in varying amounts of residue cover. The objective of this study was to measure the effects of crop residue on nutrient concentrations in runoff from areas where beef cattle or swine manure were recently applied but not incorporated. Plots 0.75 m wide by 2 m long were established at the study site. Existing residue materials were removed, and corn, soybean, or winter wheat residue was added at rates of 2, 4, or 8 Mg ha-1. Manure was then applied at rates required to meet estimated annual nitrogen requirements for corn. Control plots with manure but no residue, and plots with no residue and no manure were also established. Three 30 min simulated rainfall events, separated by 24 h intervals, were conducted at an intensity of approximately 70 mm h-1. Dissolved phosphorus (DP), total phosphorus (TP), NO3-N, NH4-N, total nitrogen, runoff, and soil loss were measured for each rainfall event. When beef cattle or swine manure was applied to plots containing residue materials, nutrient concentrations in runoff were not affected by the amount of crop residue on the soil surface. Concentrations of DP and NO3-N in runoff from the plots with beef cattle manure were significantly greater on the plots with residue than on the no-residue treatments. No significant differences in runoff nutrient concentrations were found between the residue and no-residue treatments with swine manure. Concentrations of DP and TP were significantly less on the no-residue/no-manure treatment than on the plots with beef cattle or swine manure.

The excessive application of manure on cropland areas can cause nutrients to accumulate near the soil surface. This study was conducted to measure the effects of moldboard plowing on the redistribution of nutrients within the soil profile and nutrient transport by overland flow. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha(-1) to a silty clay loam soil and then incorporated by disking. Selected plots were moldboard plowed 244 days later to a depth of approximately 23 cm. Soil samples for analysis of water-soluble phosphorus, Bray and Kurtz No. 1 phosphorus (Bray-1 P), NO3-N, and NH4-N were collected at depths of 0-5, 5-15, and 15-30 cm before and after moldboard plowing. Three 30 min simulated rainfall events, separated by 24 h intervals, were then applied. Dissolved phosphorus (DP), NO3-N. NH4-N, and total nitrogen (TN) content of runoff were measured from 0.75 wide x 2.0 m long plots. Bray-1 P content at the 0-5 cm soil depth was reduced from 200 to 48.0 mg kg(-1) and NO3-N content decreased from 9.49 to 2.52 mg kg-1 as a result of the moldboard plowing operation. Consequently, mean concentrations of DP and NO3-N in runoff decreased from 1.76 and 2.29 mg L-1 under no-till conditions to 0.03 and 0.60 mg L-1 on the moldboard plow plots. Thus, the experimental results suggest that moldboard plowing can significantly reduce concentrations of DP and NO3-N in runoff from land application areas.

Little information is currently available concerning temporal changes in nutrient transport following the addition of manure to cropland areas. This study was conducted to measure nutrient transport in runoff as affected by tillage and time following the application of beef cattle or swine manure to a site on which corn (Zea mays L.) was grown. Rainfall simulation tests were initiated 4, 32, 62, 123, and 354 days following land application. Three 30 min simulated rainfall events, separated by 24 h intervals, were conducted at an intensity of approximately 70 mm h-1. Dissolved phosphorus (DP), particulate phosphorus (PP), total phosphorus (TP), NO3-N, NH4-N, total nitrogen (TN), electrical conductivity (EC), and pH were measured from 0.75 m wide by 2 m long plots. Concentrations of DP, TP, and NH4-N, in general, declined throughout the year on both the no-till cattle and no-till swine manure treatments. Tillage did not significantly affect concentrations of DP, PP, TP, NH4-N, or pH on the swine manure treatments, but significant variations in these variables were measured over time. Under no-till and tilled conditions on both the cattle and swine manure treatments, the smallest concentrations of DP, NO3-N, NH4-N, and TN occurred on the final test date. The increase in pH of runoff during the study is attributed to the addition of CaCO3 to the rations of beef cattle and swine. Tillage appeared to have less of an impact on runoff nutrient transport from cropland areas than length of time since manure application.

To utilize manure P for crop production, P release and plant availability needs to be quantified. An incubation study was conducted to determine P availability from swine (Sus scrofa) and cattle (Bos taurus) feedlot manure in three soils. Treatments for each manure included temperature (11, 18, 25, and 32°C), water regime [constant 60% water‐filled pore space (WFPS) vs. four dry‐down cycles of 60 to 30% WFPS], time, and soils (Catlin silt loam, Sharpsburg silty clay loam, and Valentine fine sand). In another study, synthetic P fertilizer was used to determine the fraction of P that becomes unavailable with time to compare with manure P. Time, soil, and manure application were factors that influenced soil test P and water‐soluble P during incubation. At the low synthetic P fertilizer rate of 6 μg g−1, about 12 kg P ha−1, none of the applied P remained available in the Catlin soil while about one‐third remained plant available in the Sharpsburg soil and two‐thirds in the Valentine soil. At the high P rate, 68 mg kg−1, 38 to 83% of fertilizer P remained available in the three soils. Phosphorus availability was 60 to 100% of applied cattle manure P and 52 to 100% of swine slurry P in the three soils. Phosphorus availability in the Sharpsburg soil was 100% of P in both manure types. Phosphorus availability from manure is high, and manure can be used similar to inorganic P fertilizer in soils where P‐based application is made in areas susceptible to P loss in runoff. In P‐deficient soils, a P availability of 70% should be used.

The National Program structure of USDA-ARS provides an opportunity to coordinate research on problems of national and global significance. A team of USDA-ARS scientists is conducting nationally coordinated research to develop predictions of manure N availability to protect water quality and improve farm solvency. Experimental design and research protocols were developed and used in common across all participating locations. Laboratory incubations are conducted at each location with a minimum of three soils, three temperatures, two wetting/drying regimes, and two manure treatments. A soil from the central United States (Catlin silt loam, fine-silty, mixed, superactive, mesic Oxyaquic Argiudoll) is used as an internal reference across all locations. Incubation data are compiled across locations to develop generalized predictions of manure nitrogen mineralization (Nmin). Field validation data are then obtained by monitoring nitrogen (N) transformations in manure-amended soil cores equipped with anion exchange resin to capture leached nitrate. This field data will be used to compare laboratory-based predictions with field observations of Nmin in each soil, climatic zone, and manure type represented. A Decision Support System will then be developed for predicting manure N mineralization across ranges in soil, climate, and manure composition. Protocols used by this research team are provided to 1) document the procedures used and 2) offer others detailed information for conducting research on nutrient transformation processes involving collaboration across locations or complementary research between laboratory and field environments.

Practical tools are needed to identify and advance sustainable management practices to optimize economic return, conserve soil, and minimize negative off-site environmental effects. The objective of this article is to review current research in non-saline soils of the central U.S. to consider bulk soil electrical conductivity (ECa) as an assessment tool for: (1) tracking N dynamics, (2) identifying management zones, (3) monitoring soil quality trends, and (4) designing and evaluating field-scale experiments. The interpretation and utility of ECa are highly location and soil specific; soil properties contributing to measured ECa must be clearly understood. In soils where ECa is driven by NO3-N, ECa has been used to track spatial and temporal variations in crop-available N (manure, compost, commercial fertilizer and cover crop treatments) and rapidly assess N mineralization early in the growing season to calculate fertilizer rates for site-specific management (SSM). Selection of appropriate ECa sensors (direct contact, electromagnetic induction, or time domain reflectometry) may improve sensitivity to N fluctuations at specific soil depths. In a dryland cropping system where clay content dominates measured ECa, ECa-based management zones delineated soil productivity characteristics and crop yields. These results provided a framework effective for SSM, monitoring management-induced trends in soil quality, and appraising and statistically evaluating field-scale experiments. Use of ECa may foster a large-scale systems approach to research that encourages farmer involvement. Additional research is needed to investigate the interactive effects of soil, weather, and management on ECa as an assessment tool, and the geographic extent to which specific applications of this technology can be applied.

Summary This study was established on sitesthat had three or seven years of compostproduction history. Corn, wheat, barley,sorghum and alfalfa were planted in2001. In the first year, wheat, barley andsorghum performed better than corn inthe windrow areas while alfalfa did noteven establish because of excessive salt inthe soil. Soil electrical conductivity, Kand Na in the 0-6 inch depth underwindrows were high and caused soilcrusting and poor germination and cropyields. Growing salt tolerant crops, suchas barley, can rehabilitate sites used forcomposting and the process can beaccelerated by appropriate field culturalpractices. Introduction Composting manure is a usefulmethod of producing a stabilizedproduct that can be stored orspread with little odor or fly breed-ing potential. The other advantagesof composting include killingpathogens and weed seeds, andimproving handling characteristicsof manure by reducing its volumeand weight. Composting also hassome disadvantages, which includenutrient and C loss during com-posting, the cost of land, equipmentand labor required for composting,and odor associated with com-posting.Composting manure on earthensites can increase nitrate, phospho-rus and salt levels in the soil underthe compost windrows. When thecomposting operation is termi-nated, there is a need to reclaim thesites for agricultural crops. Salt tol-erant crops such as barley or wheatcan be established for one or twoyears before the site is ready foralfalfa establishment. Alfalfa hasdeep roots that can extract nitratefrom deeper in the soil profile. Theobjective of this study was to evalu-ate soil properties and performanceof corn, sorghum, barley, winterwheat and alfalfa on land previ-ously used as composting sites, andto arrive at recommendations onhow to best return such compostingsites to agricultural production.

Residual effects of manure or compost application on crop production and soil properties can last for several years. This study was conducted to evaluate residual effects of annual or biennial applications of N- and P-based composted and noncomposted beef cattle (Bos taurus) feedlot manure, chemical fertilizer, and no-treatment check on corn (Zea mays L.) production and soil properties. Manure and compost were applied from 1992 to 1995, and the residual effects were determined from 1997 to 1999. Residual effects of N- and P-based manure and compost applications on corn grain yield and N uptake lasted for at least one growing season while the effects on soil properties were longer lasting. Soil P can contribute to crop P uptake for >4 yr after N-based manure or compost application had ceased. The residual effects of manure and compost applications significantly increased soil electrical conductivity and pH levels and plant-available P and NO3-N concentrations. Four years after the last application, P leaching to a soil depth of 45 to 60 cm was observed with N-based manure or compost application. No residual effects of manure and compost applications on soil NH4-N were observed. Averaged across years, soil total C concentrations or quantities were not different among the treatments, indicating that total C was not a sensitive indicator. Residual effects of N- or P-based manure or compost application increased crop production for one year and influenced soil properties for several years.

High levels of residual soil NO3-N can contaminate ground water by leaching through the soil. Our objective was to reduce the level and spatial variability of residual soil NO3-N while maintaining optimum corn (Zea mays L.) production by variable rate N fertilizer application. The experiment was located on a 60-ha sprinkler-irrigated corn field in central Nebraska and included four N management practices: uniform rate, variable rate (VRAT), variable rate at 75% of recommended amount (VRAT @ 75%), and variable rate plus 10% (VRAT + 10%). VRAT @ 75% decreased the amount of residual NO3-N in the soil while maintaining similar grain yield to the other treatments, indicating over-application of N with treatments receiving the recommended rate. Increasing the recommended rate by 10% (VRAT + 10%) did not increase corn yield or residual soil NO3-N. Based on multifractal spectrum, no consistent pattern of spatial variability of soil NO3-N was observed for each treatment across years. Spatial variability in corn grain yield was much lower than that for soil NO3-N, indicating noneffectiveness of using soil NO3-N spatial distribution for variable rate N application unless some areas in the field are severely N deficient. Variable rate N application, did not reduce variability of residual soil NO3-N or corn grain yield as compared with uniform N. Multifractal analysis quantitatively characterized the extent and pattern of spatial and temporal variability in corn grain yield and residual soil nitrate.

Understanding how carbon, nitrogen, and key soil attributes affect gas emissions from soil is crucial for alleviating their undesirable residual effects that can linger for years after termination of manure and compost applications. This study was conducted to evaluate the emission of soil CO2, N2O, and CH4 and soil C and N indicators four years after manure and compost application had stopped. Experimental plots were treated with annual synthetic N fertilizer (FRT), annual and biennial manure (MN1 and MN2, respectively), and compost (CP1 and CP2, respectively) from 1992 to 1995 based on removal of 151 kg N ha(-1) yr(-1) by continuous corn (Zea mays L.). The control (CTL) plots received no input. After 1995, only the FRT plots received N fertilizer in the spring of 1999. In 1999, the emissions of CO2 were similar between control and other treatments. The average annual carbon input in the CTL and FRT plots were similar to soil CO2-C emission (4.4 and 5.1 Mg C ha(-1) yr(-1), respectively). Manure and compost resulted in positive C and N balances in the soil four years after application. Fluxes of CH4-C and N2O-N were nearly zero, which indicated that the residual effects of manure and compost four years after application had no negative influence on soil C and N storage and global warming. Residual effects of compost and manure resulted in 20 to 40% higher soil microbial biomass C, 42 to 74% higher potentially mineralizable N, and 0.5 unit higher pH compared with the FRT treatment. Residual effects of manure and compost on CO2, N20, and CH4 emissions were minimal and their benefits on soil C and N indicators were more favorable than that of N fertilizer.

Soils with high levels of P can contribute to excess P in runoff and subsequently pollute the surface water. Excess P in the soil can be removed from the system by harvesting crops. The objectives of this study were to evaluate corn ( Zea mays L.) P removal effects on soil P reduction, and to evaluate various corn hybrids and soybean [ Glycine max (L.) Merr.] varieties for differences in grain P concentration and P removal. Soil with varying P levels as a result of annual or biennial beef cattle ( Bos taurus ) feedlot manure or compost application was cropped to corn for 4 yr without any P addition. In other studies under various water and N regimes, corn hybrids and soybean varieties were evaluated for grain P concentration and P removal. Four years of corn production without P addition lowered surface soil (0–15 cm) extractable P level (Bray and Kurtz no. 1) from 265 mg kg −1 to 171 mg kg −1 in the biennial N‐based compost treatment. Based on a decay equation, it would have required 10 yr of corn P removal to lower the soil P level to the original 69 mg kg −1 that existed before treatment application. The rate of decrease in extractable soil P was greater when soil P was higher and reduced with decreasing soil P level. Most of the P in the plants was absorbed from the 0‐ to 15‐cm soil depth since no significant reduction in soil P level was observed from 1996 to 1999 in the 15‐ to 30‐cm soil depth. Across 2 yr, there was as much as 54% difference among corn hybrids for grain P removal. The differences in P concentrations among corn hybrids indicated that hybrids could be selected for low P uptake when lower P level in ethanol production by‐product or in animal ration and subsequently in manure is desired. Soybean grain P concentration was nearly twice that for corn but grain P removal was less for soybean than for corn. Crop P removal can significantly reduce soil P level with time.

Long-term manure and fertilizer applications to a soil can increase phosphorus (P) and nitrogen (N) transport in runoff. This study was conducted to determine P and N transport in runoff following long-term (since 1953) manure and fertilizer applications. Duplicate soil samples (32) were collected in 1998 from the top 0.1 m of selected plots of a long-term manure and fertilizer applications field experiment and later placed in 1 m(2) soil pans in the laboratory. Manure and fertilizer were mixed with 16 of the soil samples, while no treatment was applied to the other half (long-term residual effect). Simulated rainfall was then applied to the soil during initial and wet (24 hours later) events.Manure added just before simulated rainfall resulted in significantly greater concentrations of dissolved P (DP), bioavailable P (BAP), particulate P (PP), total P (TP), NO3-N, and NH4-N than when the last manure application was the previous year in 1997. Soil test P level was not a significant factor in DP loss when manure was applied just before rainfall. When the last manure application was the previous year, similar concentrations of DP, BAP, PP and TP were measured on the manure and no-manure treatments. Concentrations of NO3-N and NH4-N in runoff were not influenced by long-term fertilizer application, but significantly increased with increasing N application rate when N was applied just before rainfall. Phosphorus concentration in runoff decreased with time of runoff up to 45 minutes, after which the P concentration remained constant. NO3-N and total N concentrations continued to decrease for the entire runoff period. Manure and fertilizer should not be applied when the probability of rainfall immediately following application is great.

Accurately predicting the amount of nitrogen (N) made available for crop use by N mineralization (N-min) of native soil organic matter (SOM) is complicated by different soils, climate, and management, all highly variable from one location to the next. In this paper, we have compiled seasonal estimates of N in from eleven field studies. We only include data for native SOM and do not include organically-amended soils. Initially, the data sets were graphed and regression was performed on the data as is. To further analyze the data, and because different incubation times were used for the different studies, we normalized reported N-min to a twenty-week incubation period. Values of N-min. for a season range between 0.4 and 152 kg N ha(-1) (0.3 and 136 lb N ac(-1)). The average amount of N-min for all of these studies was 49.3 kg N ha(-1) (44 lb N ac(-1)). A graph of Nmin for all of the data against SOM shows a negative relationship. A simple linear fit on that data results in a non significant R-2 of 0.0008. A similar fit of all of the data against total N was also of little value. Eliminating the data collected from short incubations (less than fifteen weeks long) improved the fit; 42% of the variability in normalized twenty-week N-min could be explained by total N. Regression analyses of the total soil N and of SOM content on the seasonal N-min indicated that neither SOM nor total N is a good predictor for the seasonal N-min amount. Soil type, management, and climate at the various locations obviously influence the magnitude of the estimates. More importantly, this review supports the push for an accurate predictive simulation model for seasonal N-min that is non site-specific.

Rainfall patterns, soil factors, topography, climate, and land use may all influence runoff. To minimize environmental concerns, excessive runoff should be avoided on areas where manure has been applied. Management practices used to control runoff include contouring, strip cropping, conservation tillage, terraces, and buffer strips. In some cases, secondary containment systems, sedimentation basins, or ponds may be necessary to collect runoff. More than one runoff-control practice may be necessary for protection in areas with high runoff potential. Soil properties, including infiltration, may be improved by manure application. The method, rate and timing of manure application should be considered to reduce environmental impacts. The transport of nutrients and pathogens by overland flow is influenced by manure characteristics, loading rates, incorporation, and the time between manure addition and the first rainfall. Through proper management, manure can serve as a valuable nutrient source and soil amendment without causing environmental concerns.

Manure or compost application based on N needs of corn ( Zea mays L.) may result in soil accumulation of P, N, and other ions, since the manure or compost N/P ratio is usually smaller than the corn N/P uptake ratio. This study was conducted from 1992 to 1996 to evaluate the effects of annual or biennial application of N- and P-based composted and noncomposted beef cattle ( Bos taurus ) feedlot manure on soil properties. Fertilized and unfertilized checks were also included. Soil surface (0–15 cm) pH significantly increased with N-based manure (MN) or compost application (CN), but decreased with NH 4 –N fertilizer application as compared with the check. Soil bulk density was unaffected by manure or compost application. After 4 yr of manure and compost applications, soil surface (0–15 cm) C and N concentrations and quantities were greater for N- than P-based management systems. About 25% of applied manure C and 36% of applied compost C remained in the soil after 4 yr of application, indicating greater C sequestration with composted than noncomposted manure. No significant difference was observed between fertilizer and check plots for soil total C or N. Soil properties in the 15- to 30-cm increment were unaffected by the applied treatments except soil electrical conductivity (EC). Residual soil NO 3 to a depth of 1.2 m was greater for inorganic fertilizer than manure and compost treatments in drier years. Soil property changes were greater for the annual or biennial N-based than P-based manure or compost applications, reflecting the differences in application amounts.

The application of compost or fertilizer at rates that exceed crop nutrient requirements can result in phosphorus (P) and nitrogen (N) accumulation in soil. This study was conducted to determine the influence of soil P and N contents on the concentrations and total amounts of P and N transported in runoff. Composted beef cattle feedlot manure or inorganic fertilizer were added from 1992 to 1995 to a Sharpsburg silty clay loam soil at rates sufficient to meet P or N requirements for corn and incorporated following application. After four years of corn production following the last compost application, P concentration, EC, and pH of the surface soils on the N-based compost treatments were significantly greater than the check plots. Simulated rainfall was applied to the experimental site in 2000. Concentrations and total amounts of P and N in runoff were similar on the compost and inorganic fertilizer plots. The application of corn residue at a rate of 6 Mg ha -1 did not significantly affect the nutrient concentration of runoff or total nutrient transport when compared to a no-residue condition for a study site with a slope varying from 0.15% to 2.70%. On an adjoining field, compost or inorganic fertilizer were applied at rates in excess of crop P and N requirements to increase soil test P levels. For Bray and Kurtz No. 1 soil test P levels ranging from 42 to 267 mg kg -1 and water-soluble soil test P values varying from 5 to 61 mg kg -1 , the dissolved P (DP) concentration of runoff did not correlate well with soil test P. Thus, factors other than soil test P appear to influence P loss in runoff for the bare soil used in this investigation.

ABSTRACT: In order to apply manure or compost to fulfill the nutrient requirements of a crop, knowledge of the amount of nutrients mineralized following application is needed. Nutrient mineralization from applied manure depends on temperature, soil moisture, soil properties, manure characteristics, and microbial activity. Since these factors cannot be accurately predicted, nutrient mineralization from applied manure can only be approximated. Nitrogen (N) availability from applied manure includes the inorganic N (NO3-N and NH4-N) in manure plus the amount of organic N mineralized following application. Nitrogen mineralization differs for different manure types since the inorganic/organic fraction and quality of organic N varies among manure types. Mineralization of organic N is expected to be low for composted manure (∼ 18%) and high for swine or poultry (hens) manure (∼ 55%). Phosphorus (P) availability from all animal production sources of manure is high (> 70%), as most of the manure P is inorganic and becomes plant-available after application. Potassium (K) availability from manure is nearly 100%; therefore, manure can be used similar to K fertilizer. When manure was analyzed for plant-available nutrients, greater than 55% of calcium (Ca) and magnesium (Mg) and less than 40% of zinc (Zn), iron (Fe), manganese (Mn), copper (Cu), sulfur (S), and boron (B) were plant-available. To effectively utilize the nutrients in manure, their mineralization potential should be considered when determining application rates.