Mojiagou is a seasonal brook which flows directly down into the Shitoukoumen Reservoir, the key drinking water sources for Changchun City, Jilin Province. The Mojiagou watershed covers 4.286 km2, ca. 46 km east of Changchun City at approximate coordinates of 125°43′-125°46′ E and 43°53′-43°54′ N. About 39% of the land area is cropland and average slope is 6.9°, range from about 0° to slight over 31° in Mojiagou watershed. The main crop is corn (Zea mays) comprising of over 98% of the rolling cropland in the small watershed. Continuous cultivation of corn is the only conventional tillage practice for over 200 years. Dark brown soil is the zonal soil with a clay loam texture. This soil is characterized by relatively low organic matter contents of 1.7%-3.5% in the tilth horizon. Average annual precipitation is 642 mm with more than 80% of the precipitation as shower concentrated from June to September. The average annual temperature, minimum and maximum temperatures are 4.9℃, -36.7℃ and 36.2℃, respectively.