Soil conditions and yield of repeatedly grown apple orchard depending on long-term fertilizer application

Abstract

The issue of scientifically sound fertilizer application in fruit plantations, which are long-term and re-grown in one place remains insufficiently studied. To solve this problem is possible only in long-term stationary studies, as the impact of different fertilizer systems on changes in soil properties and tree productivity for a long period of their use. The results of researches of long-term fertilizer influence on the main fertility indices of dark gray podzolic heavy loam soil and productivity of repeatedly grown apple trees of Idared varieties on seed and vegetative (M4) rootstocks and Calville snow on seedling rootstock are considered. During the 85-year period of growing the first and second generation of apple trees in the experimental garden, the organic fertilizer (40 t/ha of cattle manure), mineral fertilizer (N120P120K120) and their combination (20 t/ha of manure + N60P60K60) were applied in the old plantation every two years in autumn in plowing in rows at 18–20 cm, and in the new repetition: manure, phosphorus and potassium fertilizers as well, and nitrogen fertilizer in half doses annually in spring for cultivation or disk plowing to a depth of 12–15 cm. As a result of research it was found that organic fertilizer better than mineral fertilizers provided the formation of soil fertility (humus and mobile compounds and forms of nutrients, soil reaction) and yield capacity of experimental apple trees, which for all years of fruiting exceeded the total yield of Calville snow and Idared on seedling and vegetative rootstocks, respectively, by 34.8, 27.7 and 23.4 % compared with the yield of the control non-fertilized areas and 16.0, 15.8 and 13.2 % – on those fertilized with N120Р120К120. Similar parameters of soil fertility indicators are formed by the organo-mineral fertilizer system with systematic long-term application of half the norms of organic and mineral fertilizers of manure 20 t/ha together with N60P60K60. However, the mineral system (N120P120K120) significantly less increases the humus content and content of macronutrients available for plant nutrition and does not enrich the soil with trace elements, acidifies the reaction of the soil environment