This paper presents the results obtained from a collaborative project entitled ' Reclamation of Tianjin alkali soil by desulfurization by-product, Gypsum ' during the period of 1998 to 1999. The details of this project have been described in the previous paper (Lee et al, 1998). The effect of gypsum application was tested in pot experiment with corn (Zea maize var. Chendan 7) on 6 alkaline soils from various locations within Tianjin City. The gypsum application enhanced the growth of corn on 5 soils out of 6 soils, which indicates that the gypsum is effective in ameliorating most of alkaline soils distributed in Tianjin City. The field trials were conducted in 4 locations, Lianzhuangzi, Diaokou, Luxinzhuang and Dongshunangtang. In Lianzhuangzi, the corn yield was increased by 45% due to the application of gypsum at 0.125% concentration in 1998. In Diaokou, two trials from 1998 to 1999 were conducted in the same field and the corn yields were increased by 32% in 1998 and by 22% in 1999 at 0.125% concentration, respectively. In Luxinzhuang and Dongshunangtang, Chinese cabbage (Brassica pekinensis var. Jinlu) was tested on the soils that have become alkaline because of long-term use of alkaline irrigation water. The fresh weights of Chinese cabbage were increased by 6% at 1.0% concentration in Luxinzhuang in 1998,and 6% at 0.25 concentration in Dongshunangtang in 1999,respectively. At present, it seems impossible to correlate the amount of gypsum applied to the soil with the magnitude of the increase in crop yield. However, this study clearly shows that the application of gypsum is useful in ameliorating alkaline soils and in improving the growth of corn on the alkaline soils in Tianjin City.
