Confined animal production systems produce large amounts of manure that are usually disposed on limited land areas in proximity to the source. There is concern that continuous heavy manuring may saturate the soil's capacity to retain manure‐P and result in groundwater contamination with excessive P. The objectives of this research were to determine the fate of waste‐P in heavily manured soils and assess the risk of soil and water quality degradation in turkey (Meleagris gallopavo) and beef (Bos taurus) feed lot production areas. All soils were calcareous throughout the profile. Samples were collected by 30‐cm depth increments to a depth of 210 cm or a limiting layer and were analyzed for NaHCO3‐extractable P (including inorganic and organic), and total soil P. Large amounts of extractable organic P in the surface soil layers decreased to background levels within 2 to 3 yr after manuring ceased. In heavily manured fields extractable inorganic P was well above background concentrations to as deep as 210 cm, apparently because of movement and subsequent mineralization of organic P. Organic matter in these soils was about twofold higher than background levels. There appeared to be no practical limit to the P‐retention ability of these calcareous soils. Under these conditions the risk of groundwater contamination by organic or inorganic P from waste P disposal to land is negligible.

Long-term phosphorus (P) losses and gains in sandy soils continuously fertilized with either ordinary superphosphate or coastal superphosphate (a granulated mixture of superphosphate, rock phosphate and elemental sulfur) or previously fertilized with superphosphate were investigated under leaching conditions in columns in the laboratory. The soils were subjected to 10 consecutive cycles designed to simulate the mediterranean weather conditions in the Harvey region of the Coastal Plain of Western Australia. Each cycle consisted of a wet phase during which the equivalent of 850 mm of rainfall was leached through the soil and a drier phase during which the soil was incubated in the presence of moisture equivalent to summer rainfall (150 mm). Dissolved inorganic P in the leachate was used as a measure of P loss. A sequential fractionation procedure (a resin extraction followed by 0.5 M sodium bicarbonate, 0.1 M sodium hydroxide and 0.1 M sulfuric acid extractions) and total inorganic and organic P were used to measure changes in P levels in the soils. Phosphorus losses from the previously fertilized soils decreased logarithmically with increasing number of cycles. Total inorganic P and resin-extractable P were able to explain >94% of the variation in P losses. Addition of either fertilizer increased the amount of P leached from the soil and 10-40% more P was leached by adding superphosphate rather than coastal superphosphate. The percentage of the cumulative P lost by leaching decreased with increasing application rate of both fertilizers when expressed as a percentage of the cumulative water plus citrate-soluble P added. Addition of either fertilizer increased the amount of acid-extractable P, but coastal superphosphate had a much greater effect than superphosphate. Leaching losses of P were influenced by fertilizer solubility in the short term (< 1 year). In the long term, however, the water plus citrate-insoluble P in the fertilizers also contributed to P losses by leaching.

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The role of the cloaca and lower intestine in the postrenal modification of urine was studied in conscious normally hydrated desert quail. The birds were studied for a period of 12 days during which they were in intake-output balance. It was calculated that of the combined mixture of urine-feces entering the lower intestine, 47% water, 62% sodium, and 49% potassium were reabsorbed. If this material is considered as coming from the ureteral urine, then the composition of the ureteral urine entering the lower intestine was changed as follows: 77% water, 72% sodium, and 82% potassium were reabsorbed. For urate, 68% of the total present in ureteral urine was degraded in the lower intestine. In terms of the filtered load produced by the kidneys, the lower intestine reabsorbed 1.5% filtered water, 0.4% filtered sodium, and 46% filtered potassium. The total filtered loads reabsorbed by the combined efforts of the kidney and lower intestine were 99.5% water, 99.8% sodium, and 88% potassium. It appears that the cloaca and lower intestine of birds may serve a similar function to that of the distal nephron in mammals, making the fine adjustments in water and sodium reabsorption from the urine.