Green fallow soil vs. Intensive soil cultivation - A study of soil structure along the slope gradient affected by erosion process

Abstract

The type of slope and its interaction with soil management practices are one of the most important factors affecting soil structure along the slope gradient. In this study, the effects of fallow in greening and intensive soil cultivation both located on slopes on changes soil properties especially soil structure were evaluated. Soil samples were collected from two fields (neighbouring fields) between Trakovice and Bučany villages (Slovakia). The terrain of both fields was sloping with a WN - ES orientation and a slope of <8°. Field 1 is used as arable land with intensive cultivation of crops (IC). In field 2, the fallow in greening (G) was established in 2012 and in 2018 soil samples were taken in five zones of both slopes as follows: on the summit slope, shoulder, back slope, toe slope and flat. Results showed that structure coefficient (K) was strongly affected by both land use (p = 0.0000) and slope position (p = 0.0206) as well as by the interaction of land use and slope position (p = 0.0010). The statistically significantly highest structure coefficient of water-stable aggregates (Kwsa) and opposite the lowest macro-aggregate destruction (PAD) were found for G compared to IC. In G, the index of crusting (Ic) increased by 9% compared to IC. The critical level of soil organic matter (St) was strongly affected by both land use (p = 0.0114) and slope position (p = 0.0000). The values of St were statistically significantly influenced by interaction of land use and slope position. When land use and slope position were assessed together, positive significant correlations were observed between silt and carbonate contents and Ic. On the other hand, the St values were strong effected soil organic matter (SOM) quantity and quality. In IC, positive correlations between CL (r = 0.773, P <0.01) and K were observed. Ic correlated with silt (r = 0.650, P <0.05), carbonates (r = 0.704, P <0.05) and lower humus stability. A higher silt and carbonate contents as well as higher content of SOM and better humus quality resulted in higher St values. In G, the K values positive correlated with silt and carbonate contents. Higher humus quality and stability improved soil structure evaluated on the base of Kwsa.