Local Effect on Fertility of Urine Voided by Grazing Cattle1
- J. Lotero,
- W. W. Woodhouse and
- R. G. Petersen2
A trial was conducted in an attempt to determine the local effect of urine deposited by grazing cattle on the fertility of the affected sward. Cattle were permitted to graze an unfertilized, pure stand of tall rescue at three seasons of the year: fall, spring, and summer. A number of urine spots were selected on each occasion for further study. The vegetative growth on each spot and on a comparable check area was harvested at intervals for a period of up to 2 years following deposition. The effect of urine was then measured as the difference in dry matter yield, %N and %K between the urine-treated and the nontreated vegetation. Since it is only a minor component of urine, no results are reported for the effect of phosphorus.
The following conclusions might be drawn from the results of this study:
An individual urination affects a roughly circular area with a radius of from 21 to 25 inches. That is, a total of from 9½ to 13 square feet of sward are affected per urination.
The effect is not uniform, but decreases in a linear manner from the center to the periphery of the spot.
The effect of urine decreases quite rapidly with time after deposition. As a result a urination ceases to be of practical significance within, at most, 10 months following deposition.
Both the magnitude of the effect and the rate of decrease of the effect appear to be directly related to the rate of plant growth.
Under conditions prevailing in the southeastern United States, and in the other areas where forage growth and mineral depletion are rapid, the urine returned by grazing cattle would appear to contribute little to the fertility of the pasture as a whole.
Copyright © . .