Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 2001
Publication Date: September 1, 2001
Citation: Sistani, K.R., Miles, D.M., Rowe, D.E., May, J.D. 2001. Impact of drying method, diet, and environment on phosphorus chemistry of broiler manure. Communications in Soil Science and Plant Analysis. 32:2783-2793. Interpretive Summary: Broiler manure is inherently variable in nutrient composition and its fertilizer value. Areas of intensive poultry production may be subjected to phosphorus build up due to long term manure application. Plants derive their phosphorus requirement from soil, while animals obtain most of their phosphorus need from plant materials. Most of the phosphorus in grain is not digestible, hence is excreted in the animal manure. It is critical that the manure nutrient composition be determined for the appropriate land application rate based on the needs of plant and environmental consideration. The results of our study indicated that the diet phosphorus concentration significantly affected the phosphorus content of broiler manure. Pre-analysis drying of manure significantly affected the broiler manure nutrient content regardless of diet phosphorus level. Hence, the results of this study showed that a more accurate manure chemical analysis is warranted for estimation of proper manure application rate.
Technical Abstract: Historically, manure application rate has been calculated based on nitrogen (N) needs of the crops and N content of the manure with no attention to the quantity of phosphorus (P) loading. In many instances, a gradual buildup of P in soil has resulted from long- term manure application. This study was conducted to evaluate (i), the impact of dietary P concentration on the broiler manure P content and the pre-analysis drying methods on the broiler manure nutrient composition with emphasis on phosphorus and (ii), to compare the use of Ion Chromatography and the Murphy-Riley method for the determination of inorganic phosphorus in the broiler manure water extract. Four drying methods were used to dry the fresh broiler manure as follows: air drying, freeze drying, oven drying at 65 C, and oven drying at 105 C. The results were compared with analysis of the fresh broiler manure with no drying. The diet P concentration did not affect the broiler manure total N content. However, a significant decrease in total N occurred at all P levels due to drying when compared with fresh manure analysis. The diet P level had significant effect on total P and water-extractable P. Freeze drying followed by oven drying at 105 C caused the most reduction in manure total P content. Drying also had a significant effect on the metal nutrient content of the broiler manure. However, the effect was inconsistent.