The influence of continious fertilizing on some changes in the organic substance of chernozems in North Bulgaria
1998
Gushevilov, Zh. (Institut po Pochvoznanie i Agroekologiya "N. Pushkarov", Sofia (Bulgaria))
The soil organic matter composition analysis is conducted using the Balchicova method. The investigation shows that there is an increase of humus content of the arable layer of the heavy Leached Chernozem as a result of manuring is due to the alfalfa, included in six field rotation system in Gramada. The humus content of Calcareous Chernozem of Alvanovo region has been preserved both in relation to the initial on and the unmanured soil. The humic acids are completely Ca-complexed. In light Leached Chernozem there connection with calcium is wesker. The humus in the 3 types of soil is mature. It is obvious that the fertilization significantly changes the humus content only in cases when alfalfa is included in crop rotation.
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