80 70 60 50 40 30 20 10 0 Proceedings of the International Conference on Climate Change, Biodiversity and Ecosystem Services for the 269 Sustainable Development Goals (SDGs): Policy and Practice 27-29 June 2016, Cha-am, Phetchaburi, Thailand 40 35 30 25 20 15 10 5 0 Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan 2013 2014 2015 Precipitation (mm) Air, Soil temperature (°C) and soil water content (%VWC) P Ta avg Ta max Ta min Ts avg Ts max Ts min SWC Fig.1 Daily mean air temperature (solid line), max air temperature (red closed triangle symbol), min air temperature (blue closed circle symbol) and, daily sum rainfall (solid bar in unit of mm) measured at 36 m height from the soil surface. Daily mean soil temperature (grey square dot line), max soil temperature (green cross symbol), min soil temperature (orange open circle symbol) and daily mean soil water content (brown plus symbol) in unit of% VWC at 5 cm depth during the study period. Note that Ta, Ts, P and SWC represented air temperature, soil temperature, precipitation and soil water content respectively The pattern of soil water content (SWC) in general changed corresponding to the precipitation. During the dry season (November-April) the mean SWC ranged between 10-14% VWC in addition to wet season were about 12-18% VWC. The annual mean of SWC was 13.47±3.02%VWC and maximum (25.08%VWC) o c c u r r e d i n November 2015 because we found that the rainfall lasted for 2 hours (6.00-8.00 pm) consecutively in that day (27.68 mm), while the minimum was found in April 2014 (9.67% VWC) when the dry period started. B. Monthly variations of GPP, ET and WUE Figure 2 shows the monthly patterns of gross primary productivity (GPP) during the study period which varied between 46 to 262 g C m-2 month-1 (164±55 g C m-2 month-1) and maximum was founded in wet season such as in June in 2014, while minimum was occurred in March in 2015, during dry season. These patterns were correlated significantly (R2=0.81, P<0.01) with evapotranspiration (ET) (Fig.3). The monthly of ET was ranged between 33 to 96 kg H2O m-2 month-1 (67±18 kg H2O m-2 month-1) in addition high ET was found in wet season (May to October) and the rest was found in dry season (November to April). High ecosystem water use efficiency (WUE) occurred during transition from wet to dry and varied between 1.39 to 3.39 g C kg-1 H2O during study period. The annual WUE was 2.43±0.44 g C kg-1 H2O. This study was consistent that of a warm-temperate mixed plantation in north China reported by Tong, et al. (2014), who found that WUE ranged from 1.72 to 2.41 g C kg-1 H2O
Proceedings of International Conference on Climate Change, Biodiversity and Ecosystem Services for the Sustainable Development Goals : Policy and Practice 27-29 June 2016 at the Sirindhorn International Environmental Park, Cha-am, Phetchaburi, Thailand
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