Short Term Effectiveness of Poultry Litter as a Fertilizer for Newly Established Loblolly Pine (Pinus taeda L.) Allan Pringle and Kenneth Farrish Division of Environmental Science Stephen F. Austin State University Treatments - Control – no fertilizer - DAP – 278 kg haˉ¹ = 0.492g per container - PL – Equal elemental nitrogen (N) as DAP = 1.8g PL per container - PL with Triple-Super Phosphate (TSP) (CaHPO 4 ) – Equal rate of elemental N and P of DAP treatment = 1.8g of PL g TSP per container Methods - Sand Culture Pot Study: inert medium sand, pH Study Duration of 14 weeks with a one time application of fertilizer treatments - Watered (DI water) to saturation at 10 day intervals - Growing Chamber Conditions: Photo period 26 °C with 60-65% relative humidity Dark period 20 °C with 70-75% relative humidity - Surface area of seedling containers cm² - Foliage Tissue were analyzed with a Leco C/N Analyzer for Total N, P, and K - Water Samples were analyzed with a Leco C/N Analyzer for Total N, P, and K - Diameters were measured at root collar - Heights were measured from root collar to terminal bud tip Conclusions - PL treatment did prolong nutrient supply for duration of study but was not readily adsorbed by seedlings. - DAP treatment provided the most readily available N and P at initial application but nutrient levels diminished with watering and time. - PL&TSP treatment was effective in supplying the greatest amount of K and also had a prolonged nutrient release. - Seedling growth was not significantly different among treatments. A longer study period and re-application of treatments might reveal differences. Figure 1. Foliage nutrient concentrations of each treatment in mg kgˉ¹. Figure 2. Cumulative Nutrients lost in drainage water by treatments over 14 weeks of the study. Figure 3. Average initial and final seedling diameters for each treatment. Introduction There are growing environmental concerns in East Texas about the excessive phosphorous (P) loading in soils of forage pastures adjacent to poultry farms. Poultry litter, a mixture of bedding, feed, and manure, is used as a fertilizer on these pastures to supply N for forage grasses. Repeated applications result in excess P accumulation. Because of this, there is interest in finding alternative applications for the litter. This research focuses on the potential use of litter as a forest fertilizer for loblolly pine plantations in the region. A preliminary bench study was designed to determine the effectiveness of poultry litter (PL) in supplying N, P, and K needs of newly established loblolly pine seedlings. The litter was tested against diammonium phosphate (DAP), an operational used chemical fertilizer for loblolly pine seedlings. Objective: Determine if PL will supply equal or greater amounts of macronutrients over a longer duration than DAP. Discussion Foliage N and P concentrations from the DAP treatment were significantly different except higher than the other treatments while K concentration was lowest that treatment ( mg kgˉ¹). Foliage nutrient levels for K were found at relative greater concentrations than N, and P for all treatments (Fig. 1). Nutrient levels in the drainage water of the DAP treatment were significantly greater at the initial watering (Fig. 2). Due to the significantly higher foliage concentrations of the DAP treatment there is reason to believe that the nutrients that were not lost to drainage water were absorbed by the seedlings. The PL treatment was found to have significantly lower levels of P in the foliage and the drainage water. Fig. 2 shows that more uniform amounts of nutrients were leached throughout the duration of the study in the PL treatment, which would indicate that PL provided a longer, slower release of nutrients. Environmentally a slower release of nutrients would be more beneficial in reducing leaching runoff losses and would provide nutrients to the seedlings over a longer duration. The PL&TSP treatment also displayed a slow release of nutrient in drainage water (Fig. 2). Foliage nutrient levels of K were significantly greater from the PL&TSP treatment. Although, PL&TSP foliage concentrations and drainage water levels of P were second to the amount that the DAP treatment produced. Diameter and height growth were not significantly different among treatments. Algae blooms were observed during the study on the sand surface of all fertilizer treatments causing the sand to aggregate and form a crusted layer.