Influence of organic matter on the effectiveness of mineral fertilizers.

The influence of composted peat on the effectiveness of different doses of mineral fertilizers was studied in model greenhouse experiments with barley of the Pirkka variety cultivated in sand and poorly cultivated sandy-loam soil. It was shown that the use of a large amount of composted peat (10% of the weight of the substrate) contributed under the experimental conditions to a pronounced increase in plant productivity only when increased doses of mineral fertilizers were used (NPK at 0.2 g/kg of substrate). A direct correlation between yields and number of microflora in the rhizosphere was not revealed. Conditions were modeled under which increased yield occurred when development of microflora was poor, while the lowest yields were noted when there was an increase in the number of microorganisms. At the same time, the variants with maximal numbers of microorganisms and size of yields did coincide.