Effect of long-term fertilization on some changes on phosphorus in chernozem from North Bulgaria
1998
Gushevilov, Zh. (Institut po Pochvoznanie i Agroekologiya "N. Pushkarov", Sofia (Bulgaria))
It has been found that long-term (20-24 years) has increased the content of labile phosphorus in the chernozems investigated, due to which their degree of supply has been also increased. Soil that has been fertilized for a long time, has not changed it's degree of labile phosphorus supply. However, soil fertilized for 20-24 years with low rates, has passed from low to average degree of supply, while that fertilized with average rates - to such of a good supply, and with high rates - togood or very dood supply. Most freguently, the relation between the long-term systemic phosphorus fertilization, and labile phosphorus content in soil, is a linear function.
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