Effects of long-term fertilization on growth and photosynthesis of summer maize in fluvoaquic soil

The effects of different fertilization treatments on growth development, photosynthesis and yield of summer maize were studied in a long-term field experiment in the National AgroEcological Experiment Station in Fengqiu, China, and the correlations between net photosynthetic rate, leaf area index and yield were analyzed. The results showed that plant height, leaf area index and yield of the nitrogen, phosphorus, potassium nutrientdeficiency treatments were decreased significantly compared with NPK treatments. The yields of P deficiency, N deficiency and K deficiency treatments only accounted for 10.78%, 21.14% and 83.43% of that NPK treatment, respectively. The correlations between leaf area index and yield was more significant than that between photosynthetic rate and yield, indicating that the yield in different fertilizer treatments depended primarily on the level of leaf area index, followed by the photosynthetic rate. The low yields under longterm nonfertilization or nitrogen, phosphorus, potassium nutrientdeficiency condition were mainly resulted from synthesis effects of the decreased leaf area index and net photosynthetic rate.