Dynamic water production functions for rice in North China

Alternative forms of a dynamic production function were compared, which described dry matter accumulation and seed production for rice, based on data from lysimeters and ceramic pots. Response functions were obtained for the whole growing season and for three separate growth stages covering transplanting to tillering, jointing, boot stage to heading, florescence and milk stage to harvest, respectively coefficients were determined for linear subsection functions of an incremental dry matter production function, based on the Morgan model. Exponential and third order polynomial functions were also fitted to the incremental growth rate functions. A dynamic rice production model was developed with coefficients being determined from data collected in Shenyang in 1998. The model was tested with data collected in 1999 and model sensitivity was examined. Results show that the model is well adapted to local conditions.