Effect of sources of nitrogen on yield and nitrogen absorption of potatoes

In tests with sources of N, (NH4)2SO4, when banded in the soil, usually resulted in highest tuber yield. Yields with Nitroform and sulfur-coated urea were similar to each other, and somewhat less than those from urea. Application of Aqua Humus, a humic acid derivative, in addition to several sources of N, had no significant effect on yields.