Abstract: Based on the meteorological data for the period of 1967-1999 in Shouyang County,the photosynthetic,the photo-temperature and the photo-temperature-water potential productivities were estimated,which reached at 19.34 t/ha,12.95 t/ha and 4.90 t/ha respectively.The trend of the potential climate productivity during the growing period,namely from April to September year by year showed that the photosynthetic and the photo-temperature potential reduced generally,but the reduced trend of the photo-temperature-water potential was not significant.As showed at the isoline map,all of the photosynthetic,the photo-temperature and the photo-temperature-water potentials showed a decreased trend at different degree in late 1990s.The potential climate productivity kept continued to decline after 1999.

Key words: Potential climate productivity, Potential climate productivity, Isoline map, Dryland farming, Shouyang County