A field experiment was carried out on sandy clay loam soil of the Study and Research farm Peterlauki of the Latvia University of Agriculture (LUA). The crop rotation consists of six fields with the following crop sequence: winter wheat – winter rape – spring wheat – barley – barley + clover – clover. The experiment scheme included no fertilizer treatment and nine treatments with constant potassium, four phosphorus and three nitrogen rates, what was differentiated corresponding to the demands of the growing crops. Soil samples were taken from 0 to 20 cm depth in plots before the experiment, in the middle of crop rotation and after completion of the first rotation cycle. The aim of our study was to determine the influence of crop rotation and fertilizers on the changes of soil agrochemical properties as well as grain quality indices. The obtained data showed that the tendency of decreasing soil organic matter content by 0-6.1 g kg-1 on average was still observed after the completion of full rotation cycle. Research results showed insignificant increase in soil pH values connected with parent material peculiarities and high concentration of hydrogen carbonate in soil solution. Thus, acidification in topsoil was not observed even at increased doses of single superphosphate applied. There were not observed significant changes in available phosphorus
(P) and potassium (K) under the influence of fertilizer during one rotation cycle. Peculiarities of meteorological conditions during the experimental years caused greater fluctuations in grain quality than the fertilizer applied.