The experiments were carried out in a sloped cropland on a farm field in Ban Sam Jan, Khon Kaen Province, Thailand (N1635–360 , E10247–480; 300 m a. s. l.). The experimental field covers an area extending 270 m and 510 m, with an average slope gradient of 5%. The experimental field included four sugarcane (Saccharum officinarum L.) plots on a southeastern slope and three mango (Mangifera indica L.) plantation plots on the lower position of the slope. The size of plots was 10 mx10 m. The mean annual air temperature and precipitation were 27.4 C and 1190 mm yr1,respectively. There are distinct dry and wet seasons: the dry season is from November to March and the wet season, during which most of the rainfall occurs, is from April to October. Sugarcane and cassava have been cultivated for several decades at the site, while the lower position of the sugarcane field was converted to mango plantation approximately 10 years ago. The sandy soils of both the sugarcane (SC) field and the mango (MG) plantation are classified as Typic Ustipsamments (Soil Survey Staff, 2006). These sandy soils are derived from sediments above the evaporate deposits of the Maha Sarakham Formation (Cretaceous to early Tertiary) and were formed as a consequence of long-term erosion, mass movement, and weathering (Mitsuchi et al., 1989). In the SC field, the mineral fertilizer (N 16%, P2O5 16%, K2O 8%, MgO 3.2%, and CaO 8.7%) have been applied at a rate of 0.17 Mg DW ha1 yr1 at the end of the dry season (March). This corresponds to 27 kg ha1 yr1 of N in urea form. The detailed site information is given in Funakawa et al.(2006).