THE EFFECT OF LONG-TERM APPLICATION OF DIFFERENT SOIL CULTIVATION ON THE PRODUCTIVITY OF CROP ROTATIONS

A six-plot crop rotation has been established in the maize-growing region on medium-heavy textured Chernozem at Hrusovany u Brna in 1989 with 50 per cent of cereals (sugar beet, spring barley, lucerne, lucerne, winter wheat, winter wheat) and in 1970 four-plot crop rotation with 100 per cent of cereals (grain maize, grain maize, winter wheat, winter wheat). Within these crop rotations, these systems of soil cultivation were tested. In the first system, it was tilled for crops to the depth of 0.22 to 0.24 m, in the second one, to the first component of the crop rotation and in cereals, minimum soil cultivation to the depth of 0.12 to 0.15 m was tested. In the third system, it was tilled to the first component of the crop rotation and in cereals, the seeding into untreated soil was tested. Fertilizing and plant protection was performed uniformly for all systems of soil cultivation. Particular crops in the above-mentioned crop rotations are studied in separate trials through the method of randomized blocks. The trials are conducted in time and space sequence, thus allowing the vertical and horizontal crop rotations. In this case, the productivity of crop rotations settled by cereal units horizontally over the years 1985 to 1988. The results proper of evaluations of long-term action of different soil cultivation on the productivity of crop rotations of the first sequence confirmed that soil cultivation belongs to those cultural practices which affect the yield formation only insignificantly. In cereals to which technologies of different intensity of cultivation were applied directly, the tillage, minimum soil cultivation and seeding into untreated soil provided almost identical results over the four-year average. For example, the difference between treatments of soil cultivation was at maximum 0.6 % in spring barley after sugar beet, in winter wheat after grain maize difference was 1.1 % and in winter wheat after lucerne 2.9 %. In winter wheat after wheat only in four-plot crop rotation occurred an increase in the yield in case of seeding in untreated soil by 5.4 % and in six-plot by 4.0 %. Reduced intensity of soil cultivation in the second and third systems of soil cultivation had no adverse effect on the grain maize and reflected very positively in sugar beet, while a higher tuber yield by 10.4 % was settled in the third system. The productivity of crop rotations in the four years under study was affected only insignificantly. when in six-plot crop rotation in the second system of soil cultivation in comparison with the first system. a rise in the yield of cereal units by 0.4 % appeared and in the third system by 0.7 %, in four-plot crop rotation in the second system, there was an increase by 1.3 %. and by 1.8 % in the third system. The results presented here led to the conclusion that also long-continued use of minimalizing technologies (15 to 20 years) in periodical rotations with deeper soil cultivation to the crops to which organic matter is ploughed in, is of positive influence. This is an intensification measure, as it has no negative effects on the soil fertility and rather leds to an increase in crop yields and productivity of crop rotations with demonstrable savings of labour, costs and energy.