Evaluation of saturated and near saturated hydraulic conductivity of soil under different tillage treatments

B.Sc. OLUBISI OMOBOLAJI ADIO, BSc

Master's thesis

Abstract:

Water is an indispensable factor required for the growth and development of crops. The movement of water is largely dependent on soil physical and hydraulic properties such as hydraulic conductivity which governs the ease at which water moves through the soil. The aim of this research was to evaluate the saturated Ks and near saturated K(h) hydraulic conductivity of soil under conventional (CT), reduced (RT) and no-tillage(NT), and to test the null hypothesis that the hydraulic conductivities under tillage or no-tillage do not differ. The measurement of K(h) was done with the use of Mini Disk infiltrometer (METER Group, Inc.) at pressure heads -5, -3 and -1 cm respectively for each of the tillage treatments. Ks was determined in the field with the use of Pressure infiltrometer (Matula and Kozáková 1997) and in the laboratory with the automated KSAT View device (METER Group, Inc.). The analysis of variance performed on log transformed K(h) data showed significant effect of applied pressure heads, but the differences between the CT, RT, and NT were not statistically significant probably due to very high K(h) data variations within the individual treatments. The highest K(h) values were determined for NT, then RT and the lowest for CT plot. That can be explained by the increased presence of mesopores being active within the applied pressure heads on NT and RT plots. On the other hand, the Ks values determined on NT plots were the lowest, then the RT and the highest values were determined on CT plot; documenting the importance of macropores in water movement in soil. Although the differences were clearly distinguished, they were not statistically significant. As a result, the null hypothesis has been accepted for this particular study area and time of measurement. The year 2018 was extremely dry and the soil conditions in the field were relatively difficult due to presence of big cracks and animal holes in the experimental area causing high variations of K(h) and Ks data within the individual treatments.In addition to that, the Ks and K(h) values determined in 2018 were compared to data from 2015. Significantly higher Ks and K(h) values were determined for year 2018, confirming the effect of the very dry conditions in 2018. Also a significant effect of the applied type of the infiltrometer on the resulting Ks and K(h) data has been observed within this study.

Keywords

Unsaturated hydraulic conductivity, tillage treatments, Saturated hydraulic conductivity

Jazyk práce: English

Datum vytvoření / odevzdání či podání práce: 13. 4. 2019

Obhajoba závěrečné práce

• Vedúci: Ing. Kamila Báťková, Ph.D.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme / odbor:
Sustainable Agriculture and Food Security / Sustainable Agriculture and Food Security