Mutual Effect of Gypsum and Potassium on Nutrient Productivity in the Alfalfa-Grass Sward-A Case Study.

It was assumed that the production of alfalfa in soils naturally poor in available nutrients, such as potassium (K) and calcium (Ca), depends on the use of fertilizers. This hypothesis was validated in an experiment with an alfalfa-grass mixture carried out in 2012, 2013 and 2014 on soil formed from loamy sand that had a low content of available Ca and K. The two-factor experiment consisted of two levels of applied gypsum as a source of Ca (0, 500 kg ha) and five levels of PK fertilizers (absolute control, P60K0, P60K30, P60K60 and P60K120).

Soil Fertility Clock-Crop Rotation as a Paradigm in Nitrogen Fertilizer Productivity Control.

The Soil Fertility Clock (SFC) concept is based on the assumption that the critical content (range) of essential nutrients in the soil is adapted to the requirements of the most sensitive plant in the cropping sequence (CS). This provides a key way to effectively control the productivity of fertilizer nitrogen (N). The production goals of a farm are set for the maximum crop yield, which is defined by the environmental conditions of the production process.