2 Materials and methods
2.1 Study area
This research was conducted in the province Nakhon
Ratchasima, located in the lower part of Northeast Thai-land (15°N; 102°E). The province consists of 32 dis-tricts with a total area of 20,494 km 2 (Fig. 1). An-nual average daily temperature is 27.4°C with an av-erage humidity of 71 % and an annual average rainfall
of 1,019 mm. A cool season (November to February),
hot season (March to May) and rainy season (June to
October) can be distinguished. The area is traditionally
known as a beef buffalo and beef cattle production re-gion due to large areas with unfertile soils and a low wa-ter availability that impedes crop production (Simaraks
et al. , 2003; Nakhon Ratchasima, 2008).