Leslie R. Cooperband

Relating Compost Measures of Stability And Maturity to Plant Growth

Assessment of compost maturity is important for successful use of composts in agricultural and horticultural production. We assessed the “maturity” of four different sawdust-based composts. We composted sawdust with either cannery waste (CW), duck manure (DM), dairy (heifer) manure (HM) or potato culls (PC) for approximately one year. Windrows were turned weekly for the first 60 days of composting, covered for four winter months and then turned monthly for six more months. We measured compost microbial respiration (CO2 loss), total C and N, C:N ratio, water soluble NO3-N and NH4-N, dissolved organic carbon (DOC), pH and electrical conductivity at selected dates over 370 days. Compost effects on ryegrass biomass and N uptake were evaluated in a greenhouse study. We related compost variables to ryegrass growth and N uptake using regression analysis. All composts maintained high respiration rates during the first 60 days of composting. Ammonium-N concentrations declined within the first 60 days of composting, while NO3-N concentrations did not increase until 200+ days. After 250+ days, DM and PC composts produced significantly more ryegrass biomass than either CW or HM composts. Total C, microbial respiration and water-extractable NO3-N were good predictors of compost stability/maturity, or compost resistance to change, while dissolved organic carbon, C:N ratio and EC were not. The compost NO3-N/CO2-C ratio was calculated as a parameter reflecting the increase in net N mineralization and the decrease in respiration rate. At ratio values >8 mg NO3-N/mg CO2-C/day, ryegrass growth and N uptake were at their maximum for three of the four composts, suggesting the ratio has potential as a useful index of compost maturity.

Effect of poultry litter and composts on soil nitrogen and phosphorus availability and corn production

Environmental problems associated with raw manure application might bemitigated by chemically or biologically immobilizing and stabilizing solublephosphorus (P) forms. Composting poultry litter has been suggested as a means tostabilize soluble P biologically. The objectives of this study were to assessthe nutrient (N, P) value of different-age poultry litter (PL) compostsrelativeto raw poultry litter and commercial fertilizer and determine effects ofpoultrylitter and composts on corn (Zea mays) grain yield andnutrient uptake. The research was conducted for two years on MarylandsEastern Shore. Six soil fertility treatments were applied annually to aMatapeake silt loam soil (Typic Hapludult): (1) a check without fertilizer, (2)NH4NO3 fertilizer control (168 kg Nha−1), (3) raw poultry litter (8.9 Mgha−1), (4) 15-month old poultry litter compost (68.7Mg ha−1), (5) 4-month old poultry litter compost(59 Mg ha−1) and (6) 1-month old poultry littercompost (64 Mg ha−1). We monitored changes inavailable soil NO3-N and P over the growing season and post harvest.We measured total aboveground biomass at tasseling and harvest and corn yield.We determined corn N and P uptake at tasseling.Patterns of available soil NO3-N were similar between raw PL-and NH4NO3 fertilizer-amended soils. LittleNO3-N was released from any of the PL composts in the first year ofstudy. The mature 15-month old compost mineralized significant NO3-Nonly after the second year of application. In contrast, available soil P washighest in plots amended with 15-month old compost, followed by raw PL-amendedplots. Immature composts immobilized soil P in the first year of study. Cornbiomass and yields were 30% higher in fertilizer and raw PL amendedplotscompared to yields in compost-amended treatments. Yields in compost-amendedplots were greater than those in the no-amendment control plots. Corn N and Puptake mirrored patterns of available soil NO3-N and P. Corn Puptakewas highest in plots amended with 15-month old compost and raw PL, even thoughother composts contained 1.5–2 times more total P than raw PL. There wasalinear relationship between amount of P added and available soil P, regardlessof source. The similar P availabilities from either raw or composted PL,coupledwith limited crop P uptake at high soil P concentrations, suggest that raw andcomposted PL should be applied to soils based on crop P requirements to avoidbuild-up of available soil P.

Effect of Organic Amendments on Soilborne and Foliar Diseases in Field-Grown Snap Bean and Cucumber

Several paper mills in Wisconsin have programs for spreading paper mill residuals (PMR) on land. A growing number of vegetable farmers recognize the agronomic benefits of PMR applications, but there have been no investigations on the use of PMR for control of vegetable crop diseases. Our objective was to determine the effect of PMR amendments on soilborne and foliar diseases of cucumber and snap bean grown on a sandy soil. Raw PMR, PMR composted without bulking agent (PMRC), or PMR composted with bark (PMRBC) were applied annually in a 3-year rotation of potato, snap bean, and pickling cucumber. Several naturally occurring diseases were evaluated in the field, along with in situ field bioassays. All amendments suppressed cucumber damping-off and Pythium blight and foliar brown spot of snap bean. Both composts reduced the incidence of angular leaf spot in cucumber. In a separate field experiment planted with snap bean for two consecutive years, all amendments reduced common root rot severity in the second year. In a greenhouse experiment, the high rate of PMRBC suppressed anthracnose of snap bean. These results suggest that the application of raw and composted PMR to sandy soils has the potential to control several soilborne and foliar diseases.

Strategies to Reduce Nitrate Leaching into Groundwater in Potato Grown in Sandy Soils: Case Study from North Central USA

There is increasing public concern to reduce nitrate pollution to groundwater, especially in sandy soils. Strategies to reduce nitrate leaching are developed to increase N use efficiency, reduce groundwater pollution, and increase tuber yield. A growing interest in N management should consider management strategies for N supply, soil moisture for transport, and crop N demand that are economical and compatible with local production systems. We present a review of the literature on conventional and innovative strategies for N, irrigation, and crop management for potato production in reducing N leaching in sandy soils. The amount of fertilizer-N should be decided based on an integrated evaluation of soil organic matter content, soil texture, residual soil N, crop residues, credit to organic N sources, crops to be grown including varieties and crop physiological needs, cropping systems, yield potential, water management, and N concentrations in irrigation water. Research advances have no quick fix for controlling NO3 leaching to groundwater. However, the best combination of proven strategies can reduce leaching potential significantly.ResumenExiste una preocupación pública en aumento para reducir la contaminación de nitrato en el agua del subsuelo, especialmente en suelos arenosos. Se han desarrollado estrategias para reducir la lixiviación de nitratos para aumentar el uso eficiente de N, reducir la contaminación del agua del subsuelo, y para aumentar el rendimiento de tubérculo. Un interés en aumento en manejo de N debería de considerar estrategias de manejo para suministro de N, humedad del suelo para el transporte, y demanda de N del cultivo que sean económicas y compatibles con los sistemas locales de producción. Presentamos una revisión de la literatura en las estrategias convencionales e innovativas para el manejo de N, riego y del cultivo para producción de papa en la reducción de la lixiviación de N en suelos arenosos. La cantidad del fertilizante nitrogenado deberá decidirse con base a una evaluación integrada del contenido de materia orgánica en el suelo, textura, N residual, residuos de cosecha, reconocimiento a las fuentes de N orgánico, cultivos a sembrarse incluyendo variedades y necesidades fisiológicas del cultivo, sistemas de cultivo, potencial de rendimiento, manejo del agua, y concentraciones de N en el agua de riego. Los avances en investigación no tienen un remedio rápido para controlar la lixiviación de NO3 al agua del subsuelo. No obstante, la mejor combinación de estrategias probadas pueden reducir significativamente el potencial de lixiviación.

Composting: Art and Science of Organic Waste Conversion to a Valuable Soil Resource

Composting is the manipulation of a biological process, decomposition; raw organic materials such as manure, leaves, grass clippings, food wastes, and municipal biosolids are converted to stable soil-like humic substances. Composting is an ancient technology undertaken on a variety of levels, from home to industrial. As landfills reach their capacity and ban acceptance of organic wastes, composting is an increasingly viable means of organic waste treatment. Moreover, the final product, finished compost, is a valuable soil resource with a variety of agricultural, horticultural, and silvicultural uses.

Compost Effects on Soil Physical Properties And Field Nursery Production

Field production of ornamental shrubs often results in significant topsoil removal and degradation of surface soil physical properties. Building soil organic matter through compost amendments is one way to ameliorate effects from topsoil removal in woody ornamentals production. We amended field soils with three composts to evaluate their effects on soil physical properties and shrub biomass production. Specifically, we applied either duck manure-sawdust (DM), potato cull-sawdust-dairy manure (PC) or paper mill sludge-bark (PMB) composts to a Plano silt loam soil using two application methods: 2.5 cm of compost incorporated into the top 15 cm of soil (incorporated-only) or 2.5 cm of compost incorporated plus 2.5 cm of compost applied over the soil surface (mulched). We grew three shrub species from liners: Spirea japonicum ‘Gumball’, Juniper chinensis ‘Pfitzeriana’, and Berberis thunbergia ‘Atropurpurea’. Shrub species and soil amendment treatments were established in triplicate in a randomized split plot design. Total soil carbon (TC), bulk density (ρb), aggregate stability, soil moisture retention capacity (MRC), volumetric moisture content (θv), and saturated hydraulic conductivity (Ksat) were measured over three years (1998 to 2000). We measured above and below ground shrub dry matter production at the end of the first (1998) and second (1999) growing seasons. Mulched treatments resulted in 15%-21% higher TC than the incorporated-only and no-amendment control treatments. Bulk density decreased with increasing TC contents. Greater aggregate stability and the formation of larger aggregates were related to increased TC. Field moisture retention capacity tended to be higher in the incorporated treatments compared to the mulched and nonamended control treatments. Compost amended treatments increased saturated hydraulic conductivity (Ksat) sevenfold over the nonamended control. There were no compost effects on shrub biomass until the second year of growth. Barberry was the only species to respond significantly and positively to compost application. Specifically, mulched DM compost produced 39-42% greater total Barberry biomass than the other compost treatments and the nonamended control. Our findings showed that compost effects on soil physical properties differed among composts and their subsequent effects on shrub growth were species specific.

Phosphorus source effects on soil test phosphorus and forms of phosphorus in soil

Phosphorus (P) is often supplied to field crops in organic forms such as manures or biosolids, but P availability and appropriate application rates may differ between sources. An incubation study was conducted using a Ringwood silt loam soil and seven P sources. The P sources were low, medium, and high P manure (feces) from a dairy feeding study, whole manure, fiber manure from a liquid–solid separator, biosolids from a municipal sewage treatment facility, and inorganic P applied as calcium phosphate (CaHPO4). Phosphorus sources were applied at rates of 0, 101, 202, and 404 kg total P ha−1 and incubated at 25°C. Five soil samplings were taken at 16-week intervals and analyzed for deionized water extractable P, Mehlich 3, Bray–Kurtz P1, ammonium oxalate extractable P, P saturation, bioavailable P, and anion exchange membrane extractable P. In general, the low P and fiber manures supplied the least available P, CaHPO4 the most, and medium, high, whole, and biosolids contributed intermediate amounts of P as determined by the soil P tests. The 101 and 202 kg total P ha−1 rates did not differ from each other, but were significantly lower than the 404 kg total P ha−1 rate. Except for fiber at 101 kg total P ha−1, all treatments significantly increased soil test P compared to the control. The amount of P available did not change over time except at the 404 kg total P ha−1 rate where available P usually increased with time. Correlations among soil P tests indicated significant positive relationships for each test. Bray–Kurtz P1 was most highly correlated to Mehlich 3 (r2=0.92) and least correlated to anion exchange extractable P (r2=0.13). Bioavailable P and deionized water extractable P were similarly correlated to Bray–Kurtz P1 with relatively high r2 values of 0.83 and 0.84, respectively. Ammonium oxalate extractable P and P saturation had lower r2 values (0.78 and 0.74, respectively), but were still positively correlated to Bray–Kurtz P1 and could have useful predictive value. These results indicate P availability in soil varies with the type and composition of the P source. Strong correlations among agronomic and environmental soil P tests suggest that routinely used agronomic tests or the simple DI water extractable P test could be used in place of more time consuming and expensive environmental tests to assess the P status of soils and to determine risks of various fields to release P in runoff.

Phosphorus Availability to Wheat from Manures, Biosolids, and an Inorganic Fertilizer

A greenhouse study was conducted to assess phosphorus (P) availability (as measured by plant uptake) from various P sources using Kaskaskia winter wheat (Triticum aestivum L.). The phosphorus sources included feces with low, medium, and high P concentrations from a dairy feeding study, whole (unfractionated) manure, fiber manure from a liquid–solid separator, biosolids from a municipal waste treatment facility, and calcium phosphate (CaHPO4). All P sources were applied at 0, 101, and 202 kg total P ha−1 to a sand medium. A randomized complete block design with four replicates was used. Top growth was harvested three times and roots were collected at the final harvest. An identical set of treatments was applied to a growing medium of sand plus 5% Ringwood silt loam soil. Additionally, a sub-experiment was conducted using Ringwood silt loam soil as the growing medium with whole manure, biosolids, and CaHPO4 as the P sources. Wheat total P uptake and total dry matter yield were determined for each treatment. In the sand medium, whole and low P manures produced the lowest P availability; medium P, high P, and fiber manures had intermediate P availability; and biosolids and CaHPO4 had the highest P availability. In contrast, the sand+soil experiment showed that CaHPO4, biosolids, and fiber manure produced the lowest P availability, while the other P sources (whole, low P, medium P, and high P manures) were significantly higher and similar to each other. In the soil sub-experiment, biosolids and whole manure produced significantly higher total P uptake and total dry matter yield than CaHPO4. In these studies P availability from sources with high soluble P contents was reduced in soil or sand+soil growing media possibly by reaction with Fe, Al, Mg, or Ca in the soil or adsorption of P to clay and mineral surfaces. This observation emphasizes the importance of growing media characteristics in greenhouse experiments to assess P availability. These results suggest that soluble P sorption by soil, available P contributions from soil, and mineralization of organic P from the P source treatments masked initial differences in P availability among these P sources.