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IMPORTANCE OF VISUAL EVALUATION IN ASSESSING THE
EFFECTS OF SOIL TILLAGE SYSTEMS
1, 2, Mert Acar1*,
1 ure, Department of Soil Science and Plant Nutrition, Adana, Turkey
icelik@cu.edu.tr, *macar@cu.edu.tr 2
hikmetgunal@gmail.com
The aim of this study is to assess the accuracy and sensitivity of the visual evaluation of soil structure (VESS) in determining the long-term effects of seven soil tillage practices on soil physical quality. The field experiment with three replicates was conducted on the clayey(50% clay) soil located at the Experimental and Research Station of Cukurova University in 2006. The soil tillage practices are: Conventional tillage with stubbles (CT-1), Conventional tillage with stubbles burned (CT-2), Heavy disc harrow reduced tillage (RT-1), Rototiller reduced tillage (RT-2), Heavy disc harrow zero soil tillage (HZT), no-till (NT) and strategic tillage on no-till treatment(ST). Soil horizons, thicknesses and scores of soil structures within 25 cm of soil surface were determined in three points of each treatment plotsfollowing the wheat harvest of 2017. Soil samples were analyzed for mean weight diameter (MWD), micro (MiP), macro (MaP) and total porosity (TP). Penetration resistance (PR) measurements was also performed at the same depth around the point where the VESS was performed. In reduced and no till treatments, poorer soil structures were observed in the subsurface where firm blocky and platy structures (Sq>2) weredefined. The VESS scores had significant positive correlations with PRat three depths (r=0.44, r=0.66 and r=0.52, P<0.01). In surface soils, VESS scores had also significant positive correlation with MiG (r=0.49, P<0.01), MWD (r=0.37, P<0.05), and also negative correlations with MaP and TP (r=-0.56 and r=-0.45, P<0.01).High positive correlation with PR shows that the VESS approach is effective in determining compacted layers. The VESS approach proved to be sensitive and useful in distinguishing compacted layers at different depths within thetopsoil zone. This cost effective and rapid method has the potential to be used reliably in assessing the effects of tillage applications.
