In the techniques of conservation tillage, we intervene minimally mechanically in the soil, without turning the layers, and at the same time ensure a constant cover of the cultivated area, which reduces erosion and increases biological activity in the soil, but can also increase the density of the soil, which translates into greater mechanical resistance. This work investigated how soil resistance is affected by different tillage methods and different soil textures. In long-term field experiments: TillComp (MGI texture), Kumrovo (MG texture), Mamino (I texture) and Rašica (I texture), we measured the mechanical resistance of the soil with an electronic penetrometer (Penetrologger with GPS, Eijkelkamp, NL) at three tillage intensities: conventional tillage with a plow to a depth of 25-28 cm (O), shallow tillage (E) to a depth of 10 cm and direct seeding in untreated soil (NT). Maize was planted in all trials and the yield of air-dry grain was weighed after harvest. The measurements showed a highly compacted soil layer (resistance over 2 MPa) in conventionally cultivated soils (O) at a plowing depth of 23 to 28 cm. The soils in the conservation practices (E and NT) thicken below 10 cm depth, and deeper they are more evenly compacted than (O), but the resistance rarely exceeds 2 MPa, which is the generally accepted value for limiting root growth. Regular fertilization with compost in the TillComp trial (since 1999 in doses of 10 – 20 m3/ha per year) has not resulted in significantly looser soils as expected. In general, the higher the resistance, the lower the yield, but the results of our experiments do not fully confirm this thesis, e.g. in the case of the Mamino and the TillComp experiments, where the crops were probably more strongly influenced by other factors (nutrients, soil moisture).
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