The effect of an NH4+‐enhanced nitrogen source on the growth and yield of hydroponically grown maize(Zea maysL.)

Increased above‐ground dry matter and grain yields were found for two hydroponically grown maize hybrids (Pioneer‐3925 and Pioneer‐3949) when plants were supplied with an NH4 +‐enhanced nutrient solution (31 percent of total N) compared with a control (4 percent of total N as NH4 +). The major difference in yield developed between silking and 2 weeks post‐silking and silking and 4 weeks post‐silking for the P‐3925 and P‐3949 respectively. The reduced nitrogen content of the stover (leaves plus stalk) was consistently higher on the NH4 +‐enhanced nutrient solution. The decreased production of the control treatment may have resulted from a reduced photsynthetic capacity.