J. T. Sims

PHOSPHORUS AVAILABILITY AND SORPTION IN AN ATLANTIC COASTAL PLAIN WATERSHED DOMINATED BY ANIMAL BASED AGRICULTURE

The Inland Bays watershed in southern Delaware is dominated by a large and growing poultry industry that uses land application as the primary means for disposal of manure. Runoff and drainage waters from an extensive ditch drainage system in the area eventually enter the Inland Bays. Phosphorus in these waters has been suggested as a contributing factor to eutrophication of the Inland Bays. Soil test P (STP, Mehlich 1, 0.05N HCI + 0.025N H2SO4) levels in cultivated and field border areas and P sorption maxima (PSM) were determined for selected profiles of agricultural fields and non-cultivated field borders. Relationships between PSM and soil properties and a rapidly determined p sorption index (PSI) were also investigated. STP in cultivated topsoils from 48 sites ranged from 43 to 632 mg/kg and from 42 to 568 mg/kg at 0–5 and 5–20 cm, respectively, relative to a high value for STP for agronomic crops of 35 mg/kg. STP levels were consistently greater in cultivated profiles than in field borders. Downward movement of P in some cultivated profiles occurred to a depth of 40 cm. PSM ranged from 95 to 2564 mg/kg in cultivated soils and from 200 to 2000 mg/kg in field borders. PSM was highly correlated (r = 90) with clay content and was consistently higher in subsoil horizons. When clay contents were similar, P sorption was usually greater in field borders than in cultivated fields. PSI was highly correlated with PSM (r† = 0.94) except when PSI exceeded 1400 mg/kg. This study suggests that past and current P management practices in the Inland Bays have increased soil P levels in this watershed to levels that may require much more intensive management of manure and fertilizer P in the future. Although subsoil horizons may prevent direct P leaching into groundwater, the high P values noted at the 0 to 5-cm depth and in some subsoils point to the need to assess the potential for soluble P losses in runoff and drainage waters.

Comparison of mehlich 1 and mehlich 3 extractants for P, K, Ca, Mg, Mn, Cu and Zn in atlantic coastal plain soils

Abstract The Mehlich 3 (M3) extractant was introduced in 1981 to improve the efficiency of soil testing laboratories by eliminating the need for multiple extractants for P, K, Ca, Mg, Mn, Cu and Zn. The M3 was also intended to be suitable for a wide range of soils, perhaps to serve as a “universal”; soil test extractant. At present, regional soil testing committees throughout the U.S. are investigating the M3 in this regard. Development of a field calibration data base for a new soil testing extractant is an essential, but expensive and time‐consuming process. An interim measure is the use of conversion equations between new and current extractant(s). These equations allow for use of the new extractant with existing field calibration data. The objectives of this study were (i) to develop conversion equations for the Mehlich 1 (M1) and M3 extractants for Atlantic Coastal Plain soils, and (ii) to determine the influence of soil pH and organic matter content on the relative extractability of P, K, Ca, Mg, Mn...

Nutrient removal by corn grain harvest

for crop nutrient removal are an important component of nutrient management planning and crop production. Effective nutrient management requires an accurate accounting of Although state agronomy guides and other sources nutrients removed from soils in the harvested portion of a crop. Because the typical crop nutrient values that have historically been used often publish values for crop nutrient removal, the origimay be different under current production practices, a study was nal studies on which those values are based are seldom conducted to measure nutrient uptake in grain harvested in 1998 and cited. Also, the values that were established in the past 1999 from 23 site-years in the Mid-Atlantic region of the USA. There may not be correct for current agronomic technologies were 10 hybrids included in the study, but each site grew only one such as hybrid, higher plant population, yield potential, hybrid each year. Corn (Zea mays L.) production practices followed fertilizer practice, and soil conditions. Furthermore, local state extension recommendations. Minimum, maximum, and there is a need to re-evaluate crop nutrient removal mean corn grain yields were 4.9, 16.7, and 10.3 Mg ha 1. Nutrient values for corn as several states in the Mid-Atlantic concentrations were determined on grain samples oven-dried at 70 C USA now mandate the development of comprehensive for 24 h. Minimum, maximum, and median nutrient concentration nutrient management plans (Simpson, 1998; Sims, 1999; values were as follows: 10.2, 15.0, and 12.9 g N kg 1; 2.2, 5.4, and 3.8 g P kg 1; 3.1, 6.2, and 4.8 g K kg 1; 0.13, 0.45, and 0.28 g Ca kg 1; 0.88, Pennsylvania State Conservation Commission, 1997). 2.18, and 1.45 g Mg kg 1; 0.9, 1.4, and 1.0 g S kg 1; 9.0, 89.5, and Nutrient removal values are a key component of nutri33.6 mg Fe kg 1; 15.0, 34.5, and 26.8 mg Zn kg 1; 1.0, 9.8, and 5.3 mg ent management planning because manure nutrient apMn kg 1; 1.0, 5.8, and 3.0 mg Cu kg 1; and 2.3, 10.0, and 5.5 mg B plications are being limited to the expected level of crop kg 1. Median nutrient uptake values found in this study are similar nutrient removal. to commonly used book values, but there was considerable variation The large volume of manure generated by concenamong samples of corn grain. Concentrations of P and K in grain trated animal-feeding operations in the Mid-Atlantic were positively associated with yield level, and concentrations of grain region and the environmental concerns associated with P were positively correlated with Mehlich-3 soil test P. The variability accumulation of soil P to excessive levels (Sims, 1998) in nutrient removal values seen in this study, even for the same hybrid, have focused much attention on P in nutrient manageraises questions about the usefulness of average values for estimating crop nutrient removal across a range of cropping conditions. Research ment planning. Until recently, manure application recomis needed to identify or develop a means to correct for the sources mendations were designed to match the N requirements of variability. of the crop, often leading to manure P applications in excess of crop removal. While at present, there is emphasis on P-based nutrient management planning, other F the viewpoint of sustainable agriculture, nutrinutrients may receive greater attention in the future. ent management ideally should provide a balance The objective of this study was to measure nutrient between nutrient inputs and outputs over the long term (N, P, K, S, Ca, Mg, Zn, Mn, Cu, B, and Fe) removal (Bacon et al., 1990). In the establishment of a sustainable by corn grain over a range of growing conditions in system, soil nutrient levels that are deficient are built the Mid-Atlantic region and to determine if nutrient up to levels that will support economic crop yields. To concentrations in grain were related to crop yield. The sustain soil fertility levels, nutrients that are removed study was conducted as part of a larger regional project by crop harvest or other losses from the system must on P fertility research. This allowed us to also examine be replaced annually or at least within the longer crop the relationship between soil test level and crop removal rotation cycle. When nutrient inputs as fertilizer, maof P. nure, or waste materials exceed crop removal over a period of years, soils become oversupplied and nutrient MATERIALS AND METHODS leaching and runoff become an environmental concern We grew corn in five states (Delaware, Massachusetts, (Daniel et al., 1998; Sims et al., 1998). Accurate values Maryland, New Jersey, and Pennsylvania) in 1998 and 1999 for a total of 23 site-years (Table 1). Sites were selected to J.R. Heckman, Dep. of Plant Biol. and Pathology, 59 Dudley Rd., represent the wide range of soils (Alfisols and Ultisols) and Foran Hall, Cook College, New Brunswick, NJ 08901-8520; J.T. Sims, P fertility levels within the Mid-Atlantic region. They included Dep. of Plant Sci., Univ. of Delaware, Newark, DE 19717-1303; D.B. both on-farm and research station land. Local recommendaBeegle, Dep. of Crop and Soil Sci., 116 Agric. Sci. Bldg., University tions guided cultural practices. Starter fertilizer at all sites Park, PA 16082; F.J. Coale, Nat. Resour. Sci. and Landscape Architecsupplied 15 kg P ha 1 in the form of monoammonium phosture, Univ. of Maryland, 214 H J Patterson Hall, College Park, MD phate. Spacing between rows was 0.76 m. We measured yields 20742; S.J. Herbert, Dep. of Plant and Soil Sci., Univ. of Massachusetts, from a harvested area of two 6-m rows in the middle of each Amherst, MA 01003; T.W. Bruulsema, Potash and Phosphate Inst., 18 of four replicated plots. Harris Laboratory, Lincoln, NE, anaMaplewood Drive, Guelph, ON, Canada N1G 1L8; and W.J. Bamka, Rutgers Coop. Ext. of Burlington County, 49 Rancocas St., Mount lyzed grain samples that were collected from each plot. They Holly, NJ 08060-1317. Received 2 May 2002. *Corresponding author were oven-dried at 70 C and ground in a Wiley mill to pass (heckman@aesop.rutgers.edu). Abbreviations: M3P, Mehlich-3 phosphorus. Published in Agron. J. 95:587–591 (2003).

Management and Utilization of Poultry Wastes

Waste by-products such as excreta or bedding material that are generated by the worldwide annual production of more than 40 million metric tons (t) of poultry meat and 600 billion eggs are generally land applied as the final step of a producers waste management strategy. Under proper land application conditions, the nutrients and organisms in poultry wastes pose little environmental threat. Environmental contamination occurs when land application of poultry wastes is in excess of crop utilization potential, or is done under poor management conditions causing nutrient loss from environmental factors such as soil erosion or surface runoff during rainfall. Environmental parameters of concern are N, P, and certain metals (Cu and Zn in particular), as well as pathogenic microorganisms that may be contained in poultry waste. The biochemical cycle of N is very dynamic, and N contained in poultry waste may either be removed by crop harvest, leave the animal production facility, waste treatment lagoon, or application field as a gas (NH3, NO, NO2, N2O, or N2), or, due to its mobility in soil, be transported in organic or inorganic N forms in the liquid state via surface runoff or leaching into groundwater. Elevated concentrations of NO3-N in groundwater used for human consumption is a health risk to infants that are susceptible to methemoglobinemia. An environmental impact resulting from elevated NO3-N is eutrophication of surface waters. Ammonia loss from poultry waste is an environmental concern because of volatilized wet and dry deposits of NH3 into nitrogen-sensitive ecosystems. Phosphorus in poultry wastes may contribute to environmental degradation by accelerating the process of eutrophication. Unlike N, P is very immobile in soil and must first be transported to a surface water environment to have an environmental impact. It is generally accepted, however, that this nutrient affects receiving waters via transport in eroding soil as sediment-bound P or in surface runoff as soluble inorganic or organic P. Numerous studies have reported that excess P contained in land-applied manures may contribute to eutrophication. Soils containing P concentrations that greatly exceed the agronomic potential of crops may require years or even decades to return to levels that are crop limiting for this nutrient. Environmental concerns include the capacity of such soils to adsorb new P and the amount of P loss from these soils from erosion, runoff, drainage, or leaching to groundwater. Although much information is available regarding the loss of P from agricultural fields from erosion and runoff, less information is available regarding P losses from fields receiving poultry wastes. However, studies have shown that there are many challenges to controlling P losses from fields receiving manures. In addition, subsurface transport of P resulting from repeated application of poultry manure onto soils that are artificially drained is an environmental concern where drainage waters enter or interact with water bodies sensitive to eutrophication. Trace elements such as As, Co, Cu, Fe, Mn, Se, and Zn are often added in excess to poultry feed to increase the animals rate of weight gain, feed efficiency, and egg production and to prevent diseases. Because most of the excess trace elements are not absorbed by the bird, the concentration of elements excreted in the manure will reflect dietary overformulation. Because trace elements are generally required in very small quantities for crop growth and, like P, are immobile in most soil types, their concentrations will increase with repeated land application of poultry wastes. Of particular concern are accumulations of Cu and Zn in certain soil types utilized for certain crops. Copper and Zn toxicity for some crops have been documented in some areas receiving repeated land-applied poultry wastes. A potential environmental concern relative to poultry litter and trace elements in receiving soils involves the transpor

Phosphorus soil testing: Environmental uses and implications

Abstract Phosphorus (P) soil testing has traditionally and successfully focused on rapidly measuring the level of plant‐available P in a soil and on interpreting the result in terms of the likelihood of crop response to applied P. Concern about the relationship between soil P and degradation of surface water quality has created a demand for soil testing laboratories to expand beyond their traditional scope and begin offering “Environmental P Tests”; ‐ soil tests that measure other pools of P or that offer an environmental interpretation of the analytical results. However, with new tests often come new challenges, such as the need for changes in sampling protocols, assimilation of the new test into the laboratory setting, and the development of interpretative guidelines without adequate data from long‐term field studies. In this paper we first present a summary of soil tests for P that could be used for environmental purposes, along with current interpretations and applications of these tests in the US. We...

The phosphorus footprint of China's food chain: implications for food security, natural resource management, and environmental quality.

Efficient use of phosphorus (P) for producing food, preventing water pollution, and managing a dwindling rock P reserve are major challenges for China. We analyzed P stocks and flows in the Chinese food chain to identify where P use efficiency can be improved, where P leaks to the environment, and the research, technologies, and policies needed to improve P use. We found a high degree of inefficiency; of 6652 Gg P entering the food chain, only 1102 Gg P (18%) exit as food for humans. The greatest inefficiencies were a large build-up of soil P (3670 Gg P yr; 52% of P inputs) and high P losses to the environment from animal production (1582 Gg P yr; 60% of excreted P). Improving P use in China must focus on national-scale nutrient management strategies, better animal nutrition, and adoption of technologies and policies to reduce P discharges from the animal sector and recycle P as manures in agriculture.

The driving forces for nitrogen and phosphorus flows in the food chain of china, 1980 to 2010.

Nitrogen (N) and phosphorus (P) use and losses in Chinas food chain have accelerated in the past three decades, driven by population growth, rapid urbanization, dietary transition, and changing nutrient management practice. There has been little detailed quantitative analysis of the relative magnitude of these driving forces throughout this period. Therefore, we analyzed changes in N and P flows and key drivers behind changes in the food (production and consumption) chain at the national scale from 1980 to 2010. Food (N and P) consumption increased by about fivefold in urban settings over this period but has decreased in rural settings since the 1990s. For urban settings, the integrated driving forces for increased food consumption were population growth, which accounted for ∼60%, and changing urban diets toward a greater emphasis on the consumption of animal products. Nutrient inputs and losses in crop and animal productions have continuously increased from 1980 to 2010, but the rates of decadal increase were greatly different. Increased total inputs and losses in crop production were primarily driven by increased crop production for food demand (68-96%) in the 1980s but were likely offset in the 2000s by improved nutrient management practices, as evidenced by decreased total inputs to and losses from cropland for harvesting per nutrient in crop. The contributions of animal production to total N and P losses to waters from the food chain increased by 34 and 60% from 1980 to 2010. These increases were caused mainly by decreased ratios of manure returned to cropland. Our study highlights a larger impact of changing nutrient management practice than population growth on elevated nutrient flows in Chinas food chain.

Comparison of soil test extractants used in mid-Atlantic United States

A study was conducted to develop conversion equations between the five soil test extractants commonly used by public and private soil testing laboratories serving clients in the Mid-Atlantic United States. Three hundred soil samples were selected from among the samples submitted to the University of Delaware Soil Testing Program for routine fertility analysis. The samples were extracted with Mehlich 1, Mehlich 3, Bray P1, 1 N pH 7.0 ammonium acetate and 0.1 N HCl and analyzed for phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), zinc (Zn), copper (Cu), and iron (Fe), as appropriate to the method. Significant linear relationships suitable for use as conversion equations were obtained between all extractants across a wide range of soil concentrations. Analysis of the 95% confidence bounds around the predictive equations showed large confidence intervals for some nutrient–extractant combinations (e.g., P, Mn, and Fe). Separation of the data into sub-populations based upon nutrient concentration (e.g., Mehlich 3 P200 mg P dm− 3) and subsequent statistical analysis reduced the width of the confidence interval for some, but not all, relationships. For nutrient–extractant combinations where multiple relationships have been produced for specific concentration ranges, selection of the appropriate equation should be made based upon the intended application of the resulting data and the relevant concentration range (e.g., development of agronomic nutrient recommendations would require accuracy at “low P” concentrations versus limiting P application might require accuracy at “high” P concentrations). Statistical analysis of the data set using regression analysis with the “no intercept” option produced simple conversion factors that could also be used to rapidly and easily convert the results obtained with one soil test to those of another extractant. These “simple conversion factors” had slopes and confidence intervals that were comparable to those produced using standard regression analysis. The absence of an intercept component in the resulting relationship, however, would make these conversion factors more simplistic and less cumbersome for clients to use when comparing soil test results.

Phosphorus adsorption and desorption in a sandy soil amended with high rates of coal fly ash

Abstract Amending sandy, drought‐prone soils with high rates of coal fly ash has the potential to improve plant growth by enhancing soil moisture relations. However, some studies have questioned the plant availability of native and fertilizer phosphorus (P) in ash‐amended soils. We used a batch adsorption study and a 42 day incubation study to examine the effects of amending an Evesboro loamy sand with fly ash (0–30%, w:w) on P availability and adsorption‐desorption. Fly ash increased soil test P from 13 mg/kg (soil) to 34 mg/kg (30% ash) but had little effect on readily desorbable P. The adsorption or desorption of P was not markedly influenced by fly ash in either batch or incubation studies except at the highest ash and P rates. In the batch study, the greatest increases in P adsorption were seen at the 20% and 30% ash rates and P equilibium concentrations >20 mg/L. Immediate and long‐term decreases in P desorption occurred in the incubation study at all ash rates when ≥500 mg P/kg were added but fly a...

Comparison of mehlich‐1 and mehlich‐3 extractable soil boron with hot‐water extractable boron

Abstract The standard hot water extractant for soil boron (B) was compared with two extractants currendy in use by routine soil testing laboratories, Mehlich‐1 (M‐1) and Mehlich‐3 (M‐3). If routine extractants could be used for B, it would save the time and expense required for a separate extraction. Six states (Delaware, Maryland, Virginia, North Carolina, South Carolina, and Georgia) each selected 100 soil samples sent by growers to their State laboratories which were analyzed for routine properties (pH, P, K, Ca, Mg, and organic matter) and B by M‐1 or M‐3. The samples were then analyzed for hot‐water B (HWB) using a plastic pouch procedure and inductively‐coupled plasma emission spectrometry (ICP). M‐3 extracted more B than M‐1, and the correlation coefficients for M‐3 B with HWB were higher (r = 0. 82∗∗) than were M‐l with HWB (r = 0. 74∗∗). Correlations of soil properties with M‐l and M‐3 B were higher than with HWB, but none were notable with two exceptions. Extractable Ca was positively correlated...