Some Changes of Water and Soil Chemical Properties Following Forest Fertilization

1989

S. 167-176

5 Abb., 12 Lit. Ang.

Unselbständiges Werk

200037900

Forest fertilization with ammonium nitrate is discussed in relation to acidification and nitrogen saturation. Data from some empirical studies are referred. After fertilization there is an increase in hydrogen activity in the soil solution. This effect may cause a decrease in the alkalinity of surface water, which can last at least three years. The size of the decrease in alkalinity is directly related to the acidit of the ground. The effect in surface water do not correspond to long-term effects in soil. So far, there is no clear evidence of a persistent acidification of soil and runoff water due to forest fertilization with ammonium nitrate, even at high and repeated doses - at least in the case of doses repeated at an interval of seven years. Studies in a field experiment with increasing doses of fertilizer showed that the relative retention of nitrogen within the soil was unaffected by the nitrogen dose, apart from the highest dose, which was nearly two tonnes ha-1 (3x600 kg) given during a 20-yea-period. In this case, a significantly lower relative retention of nitrogen and a persistent leakage of nitrate were found.