Soil Nutrient Accumulation in an Orchardgrass Hayfield following Poultry Litter Application

1. Soil Nutrient Accumulation in an Orchardgrass Hayfield following Poultry Litter Application R.A. Gilfillen1*, B.B. Sleugh2, W.T. Willian1, and M.L. Futrell1 Western Kentucky University1 and Dow AgroSciences, Des Moines, IA2 • Materials and Methods • General Site Information • WKU Agricultural Research and Education Complex, Bowling Green, KY • Fifteen random soil cores were taken from each plot at the end of the 4 year study to a depth of 15 cm. • Soil type: Pembroke silt loam (Mollic Paleudalf) • Soil slope: 0-2% • Fertilizer application: split application - March 26 and Aug. 30, 2001,March 21 and Aug. 16, 2002, March 24 and Aug. 22, 2003 and April 2 and August 10, 2004. • Poultry litter applications (wet weight basis) 2001 2002 2003 2004 ---------------------------Mg ha-1 PL^---------------------------- NPL: 21.0 20.3 16.0 16.0 PPL: 3.0 2.7 3.5 2.9 NPPL: 3.0 2.4 4.2 2.2 I: ----- ------ ------ ------ • Inorganic applications 2001 2002 2003 2004 ----------------------------kg ha-1--------------------------------- NPL: 0 0 0 0 PPL: 0 0 0 0 NPPL: • NH4NO3 490 587 462 574 I: • NH4NO3307 482 482 443 • 19-19-19 474 319 326 391 • 0-0-60 0 251 196 172 • Soil sample analysis: Water pH was determined using the 1:1 soil water extract. Nutrient content of soil samples was determined using Mehlich-I. Soil nutrients were analyzed via ICP. • Abstract • Poultry litter can be an excellent source of nutrients for forage production. If properly managed, litter can be returned to land; however, one concern regarding land application of poultry litter is soil nutrient accumulation. Applying poultry litter to land at recommended crop N rates can lead to an accumulation of P, K, and some micronutrients in the soil. This study was developed to observe accumulation in nutrient content of the soils after four years of fertilization with poultry litter and/or inorganic fertilizers. A completely randomized block design consisting of four treatments was utilized: an inorganic N, P, K fertilizer (I), poultry litter applied according to recommended P rate (PPL), poultry litter applied according to recommended N rate (NPL), and poultry litter applied at recommended P rate with supplemental inorganic N fertilizer (NPPL). Soil samples from the last year of the study were analyzed for pH, CEC, organic matter, and available nutrient content. Differences between treatments were found for CEC along with available P, S, Cu, Zn, and Na. In each of these measurements, the NPL treatment was significantly higher than all other (p<=0.01). Indications are that while the increased CEC would be useful, the increase in availability of P, Cu, Zn, and Na can lead to more serious environmental concerns. Cu Zn p<=0.05 p<=0.01 * • Introduction • Poultry Production in Kentucky • In 1991, there were 2.2 million broilers produced. In 2000 there were 20.8 million produced. (KASS, 2001) • Poultry production moved to the 2nd highest agricultural cash industry in 2001 (KASS, 2001). • Most of the poultry production is found in four counties in the western part of the state, • which leaves limited land area for poultry waste application due to transportation costs. • Nutrient accumulation from poultry litter application • Soil nutrient imbalances can result from long term application of incorrect litter rates (Sistani et al., 2004) • Poultry litter is high in P and some micronutrients in relationship to the quantities required by plants (Sistani et al., 2004). • There is greater concerns over P accumulations when poultry litter is applied based on N content (Sharpley et al., 2003;Franzluebbers et al., 2002). • Soil P accumulations from poultry litter application • Broiler litter applied to meet N requirements can give 8x as much P as needed (Franzluebbers et al., 2002) • Extractable P was six times greater in litter vs. non-littered soils to a depth of 60 cm (Kingery et al., 1994). • Micronutrient accumulation from poultry litter application • In littered soils, increases were seen in Cu and Zn levels which could be of concern after repeated application due to • toxicities (Kingery et al, 1994). • Results of forage production with poultry litter application • Mehlich-I extractable soil P remained constant over time when forages were removed as hay after poultry litter application • (Franzluebbers et al., 2002) • Haying of bermudagrass forage results in relatively constant Mehlich-I extractable soil P (Franzluebbers et al., 2002) OM CEC p<=0.05 • Summary • After four years of litter application, available P, K, Cu, and Zn were all observed to be highest in the NPL treatment in comparison to all others. This would again indicate that these nutrients are accumulating faster in the N rate (NPL) treatment than in the treatments involving P rate of application (NPPL or PPL) or inorganic fertilizer (I). • Organic matter content was highest in the NPL and I treatments. The NPL treatment was higher than either the NPPL or PL treatments. Cation Exchange Capacity was greater in the NPL treatment than all others. • While organic matter and CEC increases are beneficial to orchardgrass production in Kentucky, the potential environmental concerns that excess nutrients create is of greater significance. • Results and Discussion • Available Nutrient Accumulations (Figures 1 and 2) • In the NPL treatment, P, K, Cu, and Zn were all in higher concentrations than in the remaining treatments (p<=0.05 & 0.01) • Organic matter content (Figure 3) • Addition of poultry litter and additional vegetative growth led to higher organic matter contents in the NPL and I treatments in comparison to the other treatments (p<=0.05). • The I, NPPL, and PPL treatments were all similar in organic matter content (p<=0.05) • Cation exchange capacity (Figure 3) • Additions of poultry litter to meet N requirements led to higher CEC than all other treatments (p<=0.05). • References • Franzluebbers, A.J., J.A. Stuedemann, and S.R. Wilkinson. 2002. Bermudagrass management in the southern piedmont USA. II. Soil phosphorus. Soil Sci. Soc. Am. J. 66:291-298. • Kentucky Agricultural Statistics Service. 2001. Kentucky Agricultural Statistics. Frankfort, KY. • Kingery, W.L., C.W. Wood, D.P. Delaney, J.C. Williams, and G.L. Mullins. 1994. Impact of long-term application of broiler litter on environmentally related soil properties. J. Environ. Qual. 23: 139-147. • Sharpley, A.N. 2003. Soil mixing to decrease surface stratification of phosphorus in manured soils. J. Environ. Qual. 32:1375-1384. • Sistani, K.R., G.E. Brink, A. Adeli, H. Tewolde, and D.E. Rowe. 2004. Year-round soil nutrient dynamics from broiler litter application to three bermudagrass cultivars. Agron. J. 96: 525-530. • Objectives • After four years of application do soil nutrients accumulate faster and at higher amounts based on the four fertility treatments. • Determine which nutrients are accumulating in the soil that might be of environmental concern. Acknowledgements The authors wish to thank the USDA-ARS at Bowling Green and Mississippi State for providing funding and cooperation. Many thanks to the WKU Agronomy graduate and undergraduate students for assistance with field sampling and laboratory analysis.