Effects of Elevated Ammonia Concentration on Corn Growth and Grain Yield Under Different Nitrogen Application Rates

Abstract

The enhanced photosynthetic production and growth-related aspects in higher plants were reported under increasing atmospheric ammonia (NH3); however, the combined effect of elevated NH3 concentration and nitrogen (N) application rates on crop growth, growth-related aspects, and yield is poorly understood. The present study evaluated the effects of elevated NH3 concentration and N status on corn growth and grain yield in six open-top chambers (OTCs) experiments. Corn was grown for 90 days in soil-filled pots with two N application rates (with and without N (+N and −N)) and two NH3 concentrations (0 nl l−1 and 1000 nl l−1) in OTCs. Results showed that plant height, total biomass, shoot biomass, shoot/root ratio, grain yield, and 100-grain yield of corn plants were increased with decreasing application of N in the soil in the elevated NH3 treatment. Shoots biomass and grain yield were increased by 49% and 13% respectively under elevated NH3 concentration compared with ambient concentration of NH3, averaged across years and N levels. The effect of elevated level of NH3 on development and plant growth depends on the soil N status. Under N-sufficient condition, plant growth and grain yield were negatively affected, whereas in N-deprived condition, biomass production and grain yield were enhanced, because of the stimulated photosynthetic rates. Moreover, corn plants may receive more benefits from NH3 enrichment under the low supply of N nutrient and when atmospheric NH3 can act as an N supplement source.