Effects of Broiler Litter and Nitrogen Fertilization on Uptake of Major Nutrients by Coastal Bermudagrass

Land application of poultry litter provides essential nutrients for hybrid bermudagrass [Cynodon dactylon (L.) Pers.] production, but ammonia (NH3) volatilization and N mineralization influence the amount of litter N available for plant uptake. Our objective was to determine the combination of broiler litter and fertilizer N, which maximizes the yields of forage and N, P, and K by ‘Coastal’ bermudagrass. Studies were conducted for 3 yr (1999–2001) in pastures at Newton and Mize, MS that differed widely in soil test P (STP) due to history of litter application (0 vs. 301 yr, respectively.). Litter rates of 0, 4.5, 8.9, 13.4, and 17.9 Mg ha were obtained by up to four monthly (April–July) applications of 4.5 Mg ha and were supplemented with ammonium nitrate (NH4–NO3) to provide the same total N in each treatment. At Newton, combining litter with fertilizer N increased forage yield by 10% in 1999, 25% in 2000, and 34% in 2001, as compared to fertilizer N. At Mize, K uptake increased as litter rate increased in 2001 only. These responses to litter were related to increased soil P and K at Newton, and increased soil N, P, and Ca at Mize. Averaged across years, maximum P uptake of about 40 kg ha was obtained by applying 8.9 Mg litter1 134 kg N ha at Newton and 4.5 Mg litter1 202 kg N ha at Mize. Safe and effective management of major plant nutrients in broiler litter may require the use of commercial N fertilizer. NUTRIENT MANAGEMENT is essential to enhance yield, quality, and persistence of hybrid bermudagrass, an important perennial forage crop in the southeastern USA (Lang and Broome, 2003). Mississippi’s poultry industry produces about 450 000Mg ha21 of broiler litter annually (Morgan and Murray, 2002). This animal manure has long been used as a source of plant nutrients and as a soil amendment (Westerman et al., 1988; Sims and Wolf, 1994), particularly on grass pastures in south central Mississippi where broiler production is concentrated (Brink et al., 2002). Because most soils in the region are sandy, acid, and have low nutrient-holding capacity, and because commercial fertilizer prices continue to rise, broiler litter remains a valuable alternative to commercial fertilizer (Ball et al., 1996; Evers, 1998). A concern regarding repeated and/or heavy applications of litter to bermudagrass is the difference in nutrients applied vs. crop nutrient requirements may result in a build up of not only soil P, but also total N (Kingery et al., 1994; Brink et al., 2002). Water quality problems can occur if P enters the surface water in runoff, and processes of NO3 leaching loss are of concern for both economic reasons and impact on groundwater quality (Daniel et al., 1994; Pote et al., 2003). A strong positive correlation between yield and nutrient uptake by Coastal bermudagrass (Robinson, 1996; Evers, 2002; Brink et al., 2003), suggests manure management practices may involve the use of commercial N fertilizer to increase P uptake from the soil and litter and reduce P runoff (Mays et al., 1980; Pant et al., 2004). A possible mechanism for increased P uptake with N fertilization is an increase in soil solution P due to enhanced activity of rhizoshpere microorganisms (Jakobsen et al., 2005). Hybrid bermudagrass responds favorably to increasing rates of inorganic or organic N sources (Evers, 1998; Osborne et al., 1999). Response to N fertilizer is linear up to about 560 kg N ha and then becomes quadratic (Robinson, 1996). Forage dry matter (DM) yield is often stimulated by multiple N applications (Osborne et al., 1999). Soil type appears to have a minor influence on bermudagrass response to fertilizer N, but may influence its response to broiler litter (Adeli et al., 2006). Traditionally, application has been based on yield goals and knowledge of crop N utilization from the manure, but not all of the nutrients in the litter are plant available (Sims, 1986; Brink et al., 2002). So, in addition to the challenge of measuring the amount of N applied per acre, broiler litter N can be difficult to manage owing to the unpredictable effects of volatilization, mineralization, and soil type on the amount of N that becomes available to plants during the growing season (Bitzer and Sims, 1988; Adeli et al., 2006). Organic N, which comprises the greatest percentage of N in poultry manure, mineralizes over time to different inorganic forms depending on prevailing environmental conditions (Bitzer and Sims, 1988; Sims, 1986). The amount of inorganic N available to plants is affected by chemical composition of the litter and soil processes that control the amounts of NO3 and NH4 in soil solution (Gordillo and Cabrera, 1997; Adeli et al., 2006). The typical practice of surface-applying litter to perennial forages can lead to loss of N through denitrification and NH3 volatilization. Denitrification is often less in sandy textured than loamy textured soils, and coefficients range from 5% loss in well-drained soils to 50% loss in poorly-drained soils (Barton et al., 1999). J.J. Read, USDA–ARS, Waste Management and Forage Res. Unit, Mississippi State, MS 39762; G.E. Brink, USDA–ARS, U.S. Dairy Forage Res. Center, Madison, WI 53706; J.L. Oldham and W.L. Kingery, Dep. of Plant and Soil Sci., Mississippi State Univ., Mississippi State, MS 39762; K.R. Sistani, USDA–ARS, Animal Waste Management Res. Unit, 230 Bennett Lane, Bowling Green, KY 42104. Mississippi Agric. and Forestry Exp. Stn. Journal Article no. J-10770. Mention of a trademark, proprietary product or vendor does not constitute a guarantee or warranty of the product by the USDA and does not imply its approval to the exclusion of other products or vendors that also may be suitable. Received 27 July 2005. *Corresponding author ([email protected]). Published in Agron. J. 98:1065–1072 (2006).