The area has a typical subtropical humid climate with a mean annual temperature of 16.5 °C and a mean annual pre-cipitation of 1400 mm. The paddy soil is derived from a Quaternary red clay deposit and is low in phosphorus. Agricultural fertilizers used in the area include urea and carbon fertilizer, as well as some plant straw re-sidues. The field trial was established in 1998. The landform consisted of washed up terraces.