1. Effect of Ammonium to Nitrate Rations of Fertilizers Applied at Various Times Throughout the Growing Season on Yield and Nitrogen Concentrationof Corn

A number of recent investigations have produced evidenm that the ionic form of N taken up by roots affects the growth of plants. While soil- plants generally take up rest of their N as nitrate, there is evidence that increasing the relative proportion of ammonium in the culture (or soil) solution can enhance growth and yield. Owing to difficulties in prevent* the rapid miaxbial conversion of ammonium to nitrate in soil, this response has nat been well demnstrated in a field situation. The objective...