EFFECT OF LONG-TERM EROSION ON HUMUS CONTENT AND QUALITY ON CHERNOZEM SOILS

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-05-8 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 32, 179-184 pp, DOI: 10.5593/sgem2017/32/S13.024

ABSTRACT

Up to 50% of arable land is threatened by water erosion in the Czech Republic. Annually, water erosion causes billions of dollars of damage. It is especially reflected in the reduction in value of agricultural land and yield of the erosion damaged soil. In erosion affected areas, the soil is washed off and depleted of the finest particles binding nutrients and contributing to the formation of humus. In our study, we include five effects of water erosion on the content and quality of humus in chernozem, in topsoil, South Moravia- Hustopeče, the Czech Republic.
Every autumn after the harvest in 2012-2016, samples of soil (0-20 cm) were collected from three parts of the plot damaged by water erosion. Samples were taken from the top of the slope (no water erosion), middle of the slope (the greatest water erosion damage) and from the bottom of the slope, which is the accumulation part of topsoil washed off from the middle of the slope. Every year, there was cultivated wide row crop. Humus content was determined using wet method, modified Tjurin titration method where Cox is determined by oxidation of chromo-sulfuric mixtures. The quality of humus was determined by the ratio HA/FA. Statistical analysis ANOVA (Statistica) was performed to determine the effect of water erosion on the content and quality of humus.
The average content of humus for the upper part of the slope was 1.85% and the ratio of HA/FA 0.87. Humus content of the damaged middle part decreased to 0.94%, however, the quality of humus has not changed much. There was detected ratio HA/FA 0.76. At the bottom, there was an increase in humus content to 1.82% and improvement in the quality of humus to 1.23 HK/FK. Analysis of variance revealed that the water erosion does not affect the quality of the humus (HA/FA (P = 0.284) but it has a statistically significant effect on the humus content (P = 0.0001).
Our work confirmed that the long-term effect of water erosion negatively affects the humus content in the chernozem topsoil but it does not affect the quality of humus.

Keywords: humus, humus quality, chernozem, water erosion