Effects of different fertilization methods on chlorophyll fluorescence parameters and yield of summer maize

A field experiment was conducted to evaluate the effects of different fertilization methods on chlorophyll fluorescence parameters, superoxide dismutase (SOD) activity, permeability of cell membrane and yield of summer maize. The treatment of “fertilizing in seed furrow + topdressing nitrogen at jointing stage + topdressing nitrogen at big bugle stage’’ was better at increasing Fv/Fm，ФPSⅡ and qP and reducing NPQ in leaves. Both treatments of “application of controlled-release fertilizer’’ and “fertilizing in seed furrow + topdressing nitrogen at jointing stage + topdressing nitrogen at big bugle stage’’ increased chlorophyll content and superoxide dismutase (SOD) activity in leaves, and kept malondialdehyde (MDA) content and relative electrical conductivity at lower levels. Although controlled-release fertilizer increased 1000-grain weight, the treatment of “fertilizing in seed furrow + topdressing nitrogen at jointing stage + topdressing nitrogen at big bugle stage’’ had the best effect on grain yield per unit area. The data suggested that the method of “fertilizing in seed furrow + topdressing nitrogen at jointing stage + topdressing nitrogen at big bugle stage’’ should be adopted in order to get higher grain yield. But controlled-release fertilizer seemed to be a better choice to simplify the field management.