Mobile Phosphorus a nd Exchange Potassium o f Typical Black Soil i n Long Term u se o f Arable Land

Abstract

The influence of crop rotations, soil treatment methods and fertilizers on the content and balance of mobile phosphorus and exchange potassium in black soil was tested. Over the 25-year period of typical black soil use the content of mobile phosphorus increased not only under the influence of fertilizers, but also without them. The greatest impact was made by fertilizers, less significantly by crop rotations and methods of basic soil treatment. An increase in the content of mobile phosphates is observed among the tested crop rotations in grain fallow row, and from the methods of soil treatment – for small-scale processing. For five rotations of crop rotations without fertilizers, there were no significant changes in the content of exchange potassium; it remained at the level of increased security. Mineral fertilizers in double doses against the background of manure increased the content of exchangeable potassium to a high level of security. The saturation of crop rotations with row crops, as well as the use of plowing increases the content of exchangeable potassium, but to a lesser extent than fertilizers. The intensity balance of phosphorus is changed by the rotation of the crop rotation unevenly, which is associated with the magnitude of crop yield and, consequently, the removal of this element. At the same time, the general pattern of correspondence between the increase in the intensity of the balance with the increase in fertilizer application remains. Positive balance of potassium is provided only at double doses of mineral fertilizers. Manure creates a balance intensity of only 39%, which is 2.6 times less than fertilizers. Application of N42-62P62K62 against the background of 16 t/ha of manure leads to an increase in the balance intensity of more than 80%.