EFFECTIVENESS OF DIFFERENTIATION OF FERTILIZERS DOSES IN GRAIN FALLOW CROP ROTATION LINK

Abstract

To assess the efficiency of spatial differentiation of the organic and mineral fertilizer rates in the grain-fallow rotation link the landscape field trial was established in 2013 at the Menkovo experimental station of the Agrophysical Research Institute. The object of study was a historically formed plot of arable land on a mild glacial origin slope of northwestern and western expositions with total area - 53.64 ha (including 47.3 ha of plowed field and 6.34 ha of hayland). The structure of the soil cover consists of a combination of small-contour complexes of light and medium-loamy varieties of soddy gleyed podzolic and gleyic soils. Parent rock is mainly represented by thin and medium loamy and clay sandy moraine underlying by glacial sandy loam on a depth of 75 – 120cm. Soils of medium fertility with plots of high and low fertility are dominated on plowed field. Five key plots of agromicrolandscape (AML) with different geochemical regimes have been selected. The impact of zonal and precision organo-mineral fertilizer system was studied in the "complete fallow – winter wheat – oats plus perennial grasses" crop rotation. Significant differentiation of the soil cover properties of arable land on a mild slope depending on the landscape and environmental conditions was established. The transition to precision agrochemical survey is relevant. The crop rotation link productivity within the five facies of the agricultural landscape varied from 4.98 to 8.68 t/ha in the variant without fertilizer application and from 7.59 to 14.6 t/ha in the variant with fertilizer application. The sufficiency of 1 kg NPK in the fertilizer application variant varied from 1.7 to 5.6 grain units. Sufficient grounds have not been revealed to explain this variability of the indicators only with the relief location and geochemical regime. The optimization of fertilizer rates with regard to specific geochemical regimes (an increase of 12% in AML and a decrease of 14% in AML due to the redistribution of organic and mineral fertilizers) provided increase the sufficiency of 1 kg NPK by 35 %. The methodological basis of such optimization induces a need to develop more detailed scientific argumentation.