Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2004
Publication Date: 7/1/2005
Citation: Adeli, A., Sistani, K.R., Varco, J.J., Rowe, D.E. 2005. Effects of swine lagoon effluent relative to commercial fertilizer applications on warm-season forage nutritive value. Agronomy Journal. 97:408-417. Interpretive Summary: Application of animal waste to pasture lands is an effective method of recycling nutrients. It is important to evaluate the quality and nutritional values of forages treated with animal manure. Animal manure application to pasture may affect various aspects of forage quality including crude protein, fiber fractions, and digestability. Field experiments were conducted to compare the quality of two forages fertilized with swine lagoon effluent and commercial fertilizers. The results indicated that for both Bermudagrass and Johnsongrass, the crude protein content were similar for effluent and commercial fertilizer. In general, no significant differences were detected between the two sources of nutrients with regard to all forage quality parameters determined in this study. However, the forage fiber content for both forages and nutrient sources increased for late harvests. Therefore, it is recommended that Bermudagrass and Johnsongrass be harvested early in the growing season for high quality hay production.
Technical Abstract: Field experiments were conducted to evaluate the effects of variable rates of swine lagoon effluent and fertilizer on the quality parameters of forage grasses grown on an acid Vaiden silty clay (very fine, montmorillonitic, thermic, Vertic Hapludalf) and an alkaline Okolona silty clay (fine, montmorillonitic, thermic, Typic Chromudert). Treatments were multiple effluent irrigations resulting in four N, P and K rates from 0 to 665 kg N ha-1 yr-1, 94 Kg P/ha/yr, and 720 kg K ha-1 yr-1. Fertilizer treatments were also applied at equivalent N, P and K rates. A randomized complete block design with four replications was used. Regardless of N source in 1996, average annual NO3 -N concentrations increased from 116 to 1866 g g-1 dry weight for bermudagrass (Cynondon dactylon L.) and 88 to 1502 g g-1 dry weight for johnsongrass (Sorghum halepense L.) with 0 to 660 kg N ha-1. Average annual crude protein ranged from 117 to 196 g kg-1 for bermudagrass and 114 to 169 g kg-1 for johnsongrass with 0 to 660 kg N ha-1. Application of swine effluent and commercial fertilizer did not affect neutral detergent fiber (NDF) and acid detergent fiber (ADF) of both forages, but fiber contents were affected by harvesting dates. The K/(Ca+Mg) ratio for bermudagrass and johnsongrass were increased with increasing swine effluent and commercial fertilizer application rates, but the ratios were all below 2.2. Swine lagoon effluent and fertilizer had similar effects on forage quality components.