Amending pine bark with swine lagoon compost: is poo the answer?^©

INTRODUCTION
Pine bark for use in the nursery industry is in short supply and at times not completely aged due to timber processing mills moving overseas (Lu et al., 2006). Growers are working to overcome these shortages, high prices, and quality issues by using other products (such as wood) or amending pine bark to stretch their supplies (Worley et al., 2008). Calcined clays can be used as an 8% (by volume) amendment to pine bark to increase buffering and water holding capacity as well as to reduce nutrient leaching in bark based substrates (Owen et al., 2007). Utilizing composted turkey litter as an amendment (at 4, 8, 12, 16% by volume) to pine bark increased available water but decreased air space (Tyler et al., 1993). Both Owens et al. (2007) and Tyler et al. (1993) emphasize the need to evaluate both the physical and chemical properties of an amendment to pine bark before adoption by the containerized plant production industries (nurseries and greenhouses). Therefore, before implementing a new substrate mix into an operation, impacts on plant growth, nutrient availability within the substrate, and changes to fertility programs must be considered. With many alternative substrates available, growers are looking for the most locally available substrate with the least increase in cost, and the ready availability of swine lagoon waste is an attractive option.