Ardeshir Adeli

Rainfall simulation in greenhouse microcosms to assess bacterial-associated runoff from land-applied poultry litter.

Runoff water following a rain event is one possible source of environmental contamination after a manure application. This greenhouse study used a rainfall simulator to determine bacterial-associated runoff from troughs of common bermudagrass [Cynodon dactylon (L.) Pers.] that were treated with P-based, N-based, and N plus lime rates of poultry (Gallus gallus) litter, recommended inorganic fertilizer, and control. Total heterotrophic plate count (HPC) bacteria, total and thermotolerant coliforms, enterococci, staphylococci, Clostridium perfringens, Salmonella, and Campylobacter, as well as antibiotic resistance profiles for the staphylococci and enterococci isolates were all monitored in runoff waters. Analysis following five rainfall events indicated that staphylococci, enterococci, and clostridia levels were related to manure application rate. Runoff release of staphylococci, enterococci, and C. perfringens were approximately 3 to 6 log10 greater in litter vs. control treatment. In addition, traditional indicators such as thermotolerant and total coliforms performed poorly as fecal indicators. Some isolated enterococci demonstrated increased antibiotic resistance to polymixin b and/or select aminoglyocosides, while many staphylococci were susceptible to most antimicrobials tested. Results indicated poultry litter application can lead to microbial runoff following simulated rain events. Future studies should focus on the use of staphylococci, enterococci, and C. perfringens as indicators.

Bermudagrass Cultivar Response to Swine Effluent Application

Bermudagrass is the predominant forage grass grown in the region (Burton and Hanna, 1995), and hybrid Bermudagrass [Cynodon dactylon (L.) Pers.] has great potential bermudagrass responds readily to increasing N rates to recover nutrients due to its pronounced yield response to N. Our from either inorganic or organic sources (Overman et objective was to determine differences in forage dry matter (DM) al., 1993). When swine effluent was applied to Russell yield, nutrient concentration, and nutrient uptake among diverse berhybrid bermudagrass to provide 560, 1120, and 2240 kg mudagrass cultivars fertilized with swine effluent. ‘Alicia’, ‘Brazos’, N ha 1 yr 1, a yield response similar to that for inorganic ‘Coastal’, ‘Russell’, ‘Tifton 44’, and ‘Tifton 85’ hybrid bermudagrass N was observed, but efficiency of N and P recovery and common bermudagrass were grown on a Brooksville silty clay loam (fine, smectitic, thermic Aquic Hapludert) and fertilized with declined quickly with increasing effluent rate (Liu et effluent to provide 370 and 61 kg ha 1 yr 1 N and P, respectively al., 1997). Applying effluent at the two higher rates (mean of 3 yr), and on an Atwood silt loam (fine-silty, mixed, thermic resulted in large additions of N and P to the soil that Typic Paleudalf) and fertilized to provide 200 and 38 kg ha 1 yr 1 N were not recovered in the forage and were potential and P, respectively. Annual DM yields of Brazos, Coastal, Russell, contributors to ground and surface water pollution. In and Tifton 85 were similar on Brooksville (23.3–24.2 Mg ha 1) and North Carolina, Burns et al. (1985) reported that Atwood (12.3–14.1 Mg ha 1) soils. Annual N and P uptake ranged Coastal hybrid bermudagrass receiving 670 kg N ha 1 from 422 to 467 kg N ha 1 and 50 to 58 kg P ha 1 on the Brooksville and 153 kg P ha 1 from swine effluent removed an soil and from 181 to 230 kg N ha 1 and 32 to 40 kg P ha 1 on the average of 382 and 43 kg ha 1 yr 1 N and P, respectively. Atwood soil. Common bermudagrass uptake of N and P was similar Nutrient uptake by unimproved common bermudagrass, to or greater than all hybrids except Russell on Atwood soil due to prevalent throughout much of the southeastern USA, greater herbage N and P concentration. Hybrids generally recovered has not been compared with that of the hybrids when more K, Cu, and Zn than common bermudagrass. Relatively small manure served as the fertilizer source. differences in nutrient uptake among the bermudagrass cultivars sugBecause forage nutrient concentration tends to fluctugest that forage quality, winter hardiness, and establishment cost be ate little, nutrient removal is primarily a function of given equal consideration when choosing a cultivar. herbage yield (Robinson, 1996), which, among many factors, is strongly influenced by cultivar. Since the release of Coastal hybrid bermudagrass in 1943, several S production has traditionally been concenhybrid cultivars have become available to producers in trated in the Midwest (Hatfield et al., 1998), and the southeastern USA. Routine application of swine the manure has been applied primarily to soils that effluent to bermudagrass requires additional informaproduce row crops (Schmidt et al., 2001). The rapid tion about potential cultivar-dependent responses. Our growth of confined, contract swine production in the objective was to determine differences in forage DM southeastern USA (Welsh and Hubbell, 1999) has reyield and nutrient concentration and uptake among disulted in widespread application of swine effluent to verse bermudagrass varieties grown on contrasting soil forage crops. Forage crop uptake of nutrients applied types fertilized with swine effluent. with manure is often less than the quantity applied because the manure is applied at rates necessary to meet MATERIALS AND METHODS the N requirements of the forage (Sims, 1995) and the The study was conducted for 3 yr on two different confinedN/P ratio of manure does not match that of the crop feeding swine farms at Crawford, MS (33 17 N, 88 35 W), (Edwards, 1996). In addition, hay production may not on a Brooksville silty clay loam and at Houston, MS (34 0 prevent nutrient accumulation in the soil due to continN, 89 0 W), on an Atwood silt loam. At both locations, excreta ued manure application (Kingery et al., 1993). Hay prois washed from pits located below the barn floor into open duction, however, represents an important component lagoons and applied as effluent to adjacent fields using a center-pivot irrigation system (Crawford) or traveling spray gun of nutrient management. By exporting nutrients in the (Houston). Effluent had been applied to the soil at both locaform of hay from land receiving manure and by reducing tions at rates ranging from 10 to 15 cm ha 1 yr 1 (unknown runoff and soil loss, the rate of nutrient accumulation mineral concentration) for 2 to 5 yr before the experiment in the soil and the potential for ground and surface water started. Before forage yield measurements were made the first impairment may be reduced (Sims and Wolf, 1994). year, 20 soil samples were collected in the plot area at 0to 5-, 5to 15-, and 15to 30-cm depth and composited by depth. Selected soil chemical characteristics were determined using USDA-ARS, Waste Manage. and Forage Res. Unit, P.O. Box 5367, Mehlich-3 extractant (Mehlich, 1984; Table 1). Total soil N Mississippi State, MS 39762. G.E. Brink, current address: USDAconcentration was determined by the Dumas method (BremARS, U.S. Dairy Forage Res. Cent., 1925 Linden Drive West, Madiner, 1996). son, WI 53706-1108. Mississippi Agric. and Forestry Exp. Stn. Journal Alicia, Brazos, Coastal, Russell, Tifton 44, and Tifton 85 Article no. J10019. Received 7 Feb. 2002. *Corresponding author hybrid bermudagrass and common bermudagrass were estab(gebrink@wisc.edu). Abbreviations: DM, dry matter. Published in Agron. J. 95:597–601 (2003).

Poplar maintains zinc homeostasis with heavy metal genes HMA4 and PCS1

Perennial woody species, such as poplar (Populus spp.) must acquire necessary heavy metals like zinc (Zn) while avoiding potential toxicity. Poplar contains genes with sequence homology to genes HMA4 and PCS1 from other species which are involved in heavy metal regulation. While basic genomic conservation exists, poplar does not have a hyperaccumulating phenotype. Poplar has a common indicator phenotype in which heavy metal accumulation is proportional to environmental concentrations but excesses are prevented. Phenotype is partly affected by regulation of HMA4 and PCS1 transcriptional abundance. Wild-type poplar down-regulates several transcripts in its Zn-interacting pathway at high Zn levels. Also, overexpressed PtHMA4 and PtPCS1 genes result in varying Zn phenotypes in poplar; specifically, there is a doubling of Zn accumulation in leaf tissues in an overexpressed PtPCS1 line. The genomic complement and regulation of poplar highlighted in this study supports a role of HMA4 and PCS1 in Zn regulation dictating its phenotype. These genes can be altered in poplar to change its interaction with Zn. However, other poplar genes in the surrounding pathway may maintain the phenotype by inhibiting drastic changes in heavy metal accumulation with a single gene transformation.

EFFECT OF LONG-TERM SWINE EFFLUENT APPLICATION ON SELECTED SOIL PROPERTIES

Improving swine effluent management practices requires understanding of the fate of nutrients derived from swine effluent in soil quality. This study was conducted to evaluate the effects of long-term swine lagoon effluent application on nutrient distribution in an alkaline Okolona silty clay, an acidic Vaiden silty clay, and a Brooksville silty clay loam. Swine effluent has been applied using a center-pivot irrigation system at a total rate ranging from 10 to 15 cm ha−1 of effluent per year since 1990. In October 2005, soil samples were taken from the irrigated and nonirrigated sites at the following depths: 0 to 5, 5 to 15, 15 to 30, 30 to 60, and 60 to 90 cm. Soils were air-dried, ground to pass 2-mm sieve, and analyzed for selected chemical properties. Sorption isotherms were also performed on the soil samples to determine P sorption capacity and strength. Long-term application of swine effluent resulted in a decrease in soil pH and an increase in soil electrical conductivity in all three soils. Total soil C and microbial biomass C increased in irrigated sites for all soils. Soil ammonium, nitrate, acid-extractable P, water-soluble P, and Zn concentrations were elevated at the 0- to 5-cm and 5- to 15-cm depths, and their values were extremely lower in the alkaline Okolona soil than in the Brooksville and Vaiden soils. No clear effect was observed for P sorption strength and capacity. Low N and P accumulation in alkaline Okolona soil may prolong the capacity of this soil in receiving swine effluent particularly if threshold water-soluble P and soil test P levels are used as part of swine effluent management program.

Characterization of Selected Nutrients and Bacteria from Anaerobic Swine Manure Lagoons on Sow, Nursery, and Finisher Farms in the Mid-South USA

Swine (Sus scrofa domestica) production in the Mid-South USA comprises sow, nursery, and finisher farms. A 2007 packing plant closure started a regional shift from finisher to sow and nursery farms. Changes in manure stored in lagoons and land-applied as fertilizer were expected but were unknown because nutrient and bacterial levels had not been characterized by farm type. The objectives of this study were to quantify selected nutrients and bacteria, compare levels by farm types, and project impacts of production shifts. Nutrients and bacteria were characterized in 17 sow, 10 nursery, and 10 finisher farm lagoons. Total and thermotolerant coliforms, Escherichia coli (Migula) Castellani and Chalmers, Enterococcus spp., Clostridium perfringens (Veillon and Zuber) Hauduroy et al., Campylobacter spp., Listeria spp., and Salmonella spp. were evaluated. Highest levels were from total coliforms (1.4- 5.7x10(5) cfu 100 mL(-1)), which occurred with E. coli, Campylobacter spp., C. perfringens, and Enterococcus spp., in every lagoon and virtually every sample. Lowest levels were from Listeria spp. and Salmonella spp. (<or=1.3x10(2) most probable number [MPN] 100 mL(-1)), detected in 81 and 89% of lagoons and 68 and 64% of samples, respectively. Sow farm levels were higher for all except Listeria spp. and Salmonella spp., which were lower (1.4x10(1) and 2.8x10(1) MPN 100 mL(-1), respectively) and only slightly below their respective levels from nursery farms (1.1x10(2) and 3.4x10(1) MPN 100 mL(-1)). Shifting from finisher to nursery farm would not affect bacterial levels, but shifting to sows would. Either shift would reduce NPK and N:P and suggest modification of nutrient management plans.

Broiler Litter Application Effects On Selected Trace Elements Under Conventional And No-till Systems

This study was conducted on two separate commercial farms representing no-till at Coffeeville and conventional tillage system at Cruger in Mississippi to evaluate the dynamics of selected some trace elements in response to long-term broiler litter application to cotton. The soil at Cruger is a Dubbs silt loam (fine-silty, mixed, active, thermic Typic Hapludalfs) and at Coffeeville is an Ariel silt loam (coarse-silty, mixed, thermic Fluventic Dystrochreps). In each site, the experimental design was a randomized complete block with eight treatments replicated four times. Treatments included broiler litter rates of 0, 2.2, 4.5, and 6.7 Mg ha−1 in some combination with 0, 34, and 67 kg nitrogen ha−1. Commercial nitrogen, phosphorus, and potassium fertilizer at recommended rate was also included. At Coffeeville location at the end of third year, soil surface (0-15 cm) total C and total copper (Cu), zinc (Zn), and arsenic (As) significantly increased with increasing broiler litter applications. In Coffeeville under the no-till system, application of broiler litter at the highest rate (6.7 Mg ha−1) significantly increased soil surface (0-15 cm) total C, total Cu, Zn, and As by 28%, 67%, 51%, and 69%, respectively, as compared with unfertilized control. At Cruger location, changes in soil C and trace elements were less responsive to treatment applications. Downward movement of Cu and Zn was limited to 15 cm of soil depth, but As was detected at about 30 cm of soil depth at high broiler litter application rate. Despite elevated concentrations of trace metals at the soil surface, their concentrations in the soils were in the range considered normal with no potential threat to the ecosystems.

Temporal flux and spatial dynamics of nutrients, fecal indicators, and zoonotic pathogens in anaerobic swine manure lagoon water.

Confined animal feeding operations (CAFOs) often use anaerobic lagoons for manure treatment. In the USA, swine CAFO lagoon water is used for crop irrigation that is regulated by farm-specific nutrient management plans (NMPs). Implementation of stricter US environmental regulations in 2013 will set soil P limits; impacting land applications of manure and requiring revision of NMPs. Precise knowledge of lagoon water quality is needed for formulating NMPs, for understanding losses of N and C in ammonia and greenhouse gas emissions, and for understanding risks of environmental contamination by fecal bacteria, including zoonotic pathogens. In this study we determined year-round levels of nutrients and bacteria from swine CAFO lagoon water. Statistical analysis of data for pH, electrical conductivity (EC), inorganic and organic C, total N, water-soluble and total minerals (Ca, Cu, Fe, K, Mg, Mn, P, and Zn) and bacteria (Escherichia coli, enterococci, Clostridium perfringens, Campylobacter spp., Listeria spp., Salmonella spp., and staphylococci) showed that all differed significantly by dates of collection. During the irrigation season, levels of total N decreased by half and the N:P ratio changed from 9.7 to 2.8. Some seasonal differences were correlated with temperature. Total N and inorganic C increased below 19 °C, and decreased above 19 °C, consistent with summer increases in ammonia and greenhouse gas emissions. Water-soluble Cu, Fe, and Zn increased with higher summer temperatures while enterococci and zoonotic pathogens (Campylobacter, Listeria, and Salmonella) decreased. Although their populations changed seasonally, the zoonotic pathogens were present year-round. Increasing levels of E. coli were statistically correlated with increasing pH. Differences between depths were also found. Organic C, total nutrients (C, Ca, Cu, Fe, Mg, Mn, N, P, and Zn) and C. perfringens were higher in deeper samples, indicating stratification of these parameters. No statistical interactions were found between collection dates and depths.

Swine Effluent Application Timing and Rate Affect Nitrogen Use Efficiency in Common Bermudagrass

Bermudagrass [Cynodon dactylon (L.) Pers.] hay production is integral to manure management on southeastern swine farms. But swine effluent timing must be synchronized with crop nitrogen (N) demands to decrease the potential for soil N accumulation and nitrate (NO(3)) leaching. Field studies were conducted on a Prentiss sandy loam (coarse-loamy, siliceous, semiactive, thermic Glossic Fragiudult) to determine N-use efficiency (NUE) and residual soil NO(3)-N. Two rates of 10 and 20 cm yr(- 1) ( approximately 260 and 480 kg ha(-1) N, respectively) were applied in four timing treatments: April to September (full season), April to May, June to July, and August to September. Plots were harvested every 7 to 9 wk beginning in June, and soil was sampled in fall after a killing frost and the following spring. Annual uptake of N and P were least in the August to September timing treatment. Doubling the effluent rate increased N uptake 112% in 2000 (from 130 to 276 kg ha(-1)) and 53% in 2001 (from 190 to 290 kg ha(-1)), suggesting 10-cm did not meet crop N demands. Due to low rainfall and decreased forage yield in 2000, doubling the effluent rate led to increased soil NO(3)-N to 30-cm depth in fall 2000 and spring 2001. Averaged across timing treatments, soil NO(3)-N at 5-cm depth ranged from 8.5 mg kg(-1) in non-irrigated controls to 39.6 mg kg(-1) with 20-cm effluent. Results indicate low NUE in the order of 30 to 38% for applications in August to September increase the risk to surface and ground water quality from excess N remaining in soil.

Trend Analysis and Forecast of Precipitation, Reference Evapotranspiration, and Rainfall Deficit in the Blackland Prairie of Eastern Mississippi

AbstractTrend analysis and estimation of monthly and annual precipitation, reference evapotranspiration ETo, and rainfall deficit are essential for water-resources management and cropping-system design. Rainfall, ETo, and water-deficit patterns and trends at Macon in eastern Mississippi for a 120-yr period (1894–2014) were analyzed for annual, seasonal, and monthly periods. The analysis showed historical average annual rainfall, ETo, and dryness index (DI) in the location to be 1307 mm, 1210 mm, and 0.97, respectively. Monthly rainfall and ETo ranged from 72 to 118 mm and from 94 to 146 mm, respectively, between May and October, resulting in a monthly rain deficit from 22 to 62 mm. Annual rainfall showed an increasing trend of 1.17 mm yr−1 while annual ETo exhibited a decreasing trend of −0.51 mm yr−1, resulting in an annual DI reduction of 0.001 per year. Seasonal trends were found for rainfall in autumn (1.06 mm yr−1), ETo in summer (−0.29 mm yr−1) and autumn (−0.18 mm yr−1), and DI in autumn (−0.006). ...

The effect of poultry manure application rate and AlCl3 treatment on bacterial fecal indicators in runoff

Increasing costs associated with inorganic fertilizer have led to widespread use of broiler litter. Proper land application, typically limiting nutrient loss, is essential to protect surface water. This study was designed to evaluate litter-borne microbial runoff (heterotrophic plate count bacteria, staphylococci, Escherichia coli, enterococci, and Clostridium perfringens) while applying typical nutrient-control methods. Field studies were conducted in which plots with high and low litter rates, inorganic fertilizer, AlCl(3)-treated litter, and controls were rained on five times using a rain generator. Overall, microbial runoff from poultry litter applied plots was consistently greater (2-5 log(10) plot(-1)) than controls. No appreciable effect on microbial runoff was noted from variable litter application rate or AlCl(3) treatments, though rain event, not time, significantly affected runoff load. C. perfringens and staphylococci runoff were consistently associated with poultry litter application, during early rain events, while other indicators were unreliable. Large microbial runoff pulses were observed, ranging from 10(2) to 10(10) CFU plot(-1); however, only a small fraction of litter-borne microbes were recoverable in runoff. This study indicated that microbial runoff from litter-applied plots can be substantial, and that methods intended to reduce nutrient losses do not necessarily reduce microbial runoff.