Effect of vegetation change from forest to herbaceous vegetation cover on soil moisture and temperature regimes and soil water chemistry Ufuk Özkan, Ferhat Gökbulak ⁎ Istanbul University, Faculty of Forestry, Department of Watershed Management, Bahçeköy, Istanbul, Turkey abstract article info Article history: Received 28 March 2016 Received in revised form 17 September 2016 Accepted 19 September 2016 Available online xxxx Objective of this study was to compare the effects of forest and herbaceous vegetation covers on soil tempera- tures (average daily maximum, minimum, and mean daily temperatures), soil moisture, and chemical content of the soil water. Soil moisture and soil temperature were monitored at three different soil depths (40, 80 and 120 cm) and rain water samples and soil water samples from 40 cm and 80 cm soil depths were collected for 20 weeks on a weekly basis depending on precipitation events. Soil water samples were analyzed for total alka- linity, total nitrogen, calcium hardness, chloride, electrical conductivity, organic matter, pH, potassium, sodium, sulfate, and total hardness. Experiment was as a 3-way factorial in a split plot design with whole plots in blocks and repeated measures with two replications. Data were analyzed by using ANOVA and means were separated with Tukey test. Soils under the forest and herbaceous vegetation covers showed significant difference in terms of overall mean daily maximum, minimum, and average daily temperatures. Overall average daily maxi- mum and minimum temperatures were 9.94 °C and 9.75 °C, respectively for the soils in the forest plot while they were 11.08 °C and 10.87 °C for those in the herbaceous plot. Woody vegetation removal significantly in- creased overall mean daily temperature from 9.84 °C to 10.98 °C and overall mean daily volumetric soil moisture content of the soils from 32% to 48%. Chemical content of the soil water from both study sites were similar except for chloride and sulfate content. Soil water from forestland had a lower chloride but higher sulfate content than the soils from herbaceous vegetation covered area. On the other hand, chemical content of the soil water from forestland did not show significant changes with soil depth while total alkalinity, calcium hardness, electrical conductivity, pH, sodium, sulfate, and total hardness increased significantly with soil depth in the soils under her- baceous vegetation cover. © 2016 Elsevier B.V. All rights reserved. Keywords: Soil temperature Soil moisture Clearcutting Soil water chemistry Vegetation change 1. Introduction Watersheds includes several landuse types that have important im- pacts on quality and quantity of the streamwater (Huang et al., 2013). Among the land use types, forest ecosytems provide the best quality fresh water in a sustainable manner (Neary et al., 2009) but they con- sume much more water than other ecosystems due to interception and transpration losses (Grelle et al., 1999; Kosugi and Katsuyama, 2007; Özhan et al., 2010; García-Santos, 2012). Since the presence of forest cover has an important effect on microclimate and the amount of precipitation reaching soil surface, land cover changes from forest to herbaceous vegetation can affect quality and quantity of the streamwaters in the watersheds. In arid and semiarid regions, plant growth can be limited due to low soil moisture availability and high soil temperatures. Therefore, there is heightened interest for removing trees to increase soil moisture in the semiarid regions around the world (Hungerford and Babbitt, 1987; Fleming et al., 1998; Garduńo et al., 2010). Additionally, vegetation transformation from one type to an- other increases as a result of human intervention due to population growth and demand for forest resources (Song et al., 2013). In general, the greatest changes in the soil moisture content and soil temperature occur after forest vegetation removal because of increased solar radia- tion on the soil surface and decreased transpration and interception ca- pacities of the forest canopy (Hungerford and Babbitt, 1987; Carlson and Groot, 1997; Bhatti et al., 2000; Smit and Retman, 2000; Ritter et al., 2005; Scharenbroch and Bockheim, 2007). Morecroft et al. (1998) reported that much smaller range of temperatures was measured in the soils under forest cover compared to soils under grass cover. Woody vegetation clearance affects not only moisture availability in the soil but also chemical content of the soil water and soil temperature. On the other hand, climate change is a reality and natural phenomen. Due to global warming, vegetation pattern can be altered and this case can result in permanent vegetation and soil losses and changes in soil moisture and temperature and hence soil chemisrty. Soil moisture and temperature are important ecological factors which play important roles in chemical, hydrological, and biological processes in the soil (Bhatti et al., 2000). For instance, soil moisture and temperature Catena 149 (2017) 158–166 ⁎ Corresponding author. E-mail address: fgokbulak@istanbul.edu.tr (F. Gökbulak). http://dx.doi.org/10.1016/j.catena.2016.09.017 0341-8162/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Catena journal homepage: www.elsevier.com/locate/catena