Corn is a heavy feeder. My soil is very high in everything especially phosphorus, but my pH is about 6.0. I still use a little starter nitrogen but I divide the total nitrogen into a couple of separate side dressing. Also, I use a slow N fertilizer.
I can’t really find nitrogen only fertilizer that does not contain anything else. With my low pH, I can use chicken manure as is has an NPK of approx 3.0-0.5-0.5. It is also loaded with calcium which brings my pH up about 0.5 points. Only half the nitrogen is available. Otherwise, I use a 6-4-6 fertilizer with slow N as a starter and the side dressings are sulfate of ammonia. I could use urea since I don’t want the pH to drop any more, but I have a hard time controlling the amount since it is twice as potent at 46-0-0. I did add dolomite lime this year to correct pH. My other plots are strongly alkaline, approaching a pH of 8.0.
They are chronically nitrogen-poor and require much more nitrogen to get a good crop than my acidic plot. Those plots are rich in highly alkaline composts. I have had to plant green manure prior to planting the main crop and they have been sulfured as well. And I get good results but it will not last for a second planting. I don’t see micronutrient deficiencies, but the plants are a lot smaller in the alkaline soils than in my acidic plot.
I add about 2-3 inches of compost to the garden every time I plant. The local compost tests at a pH of 8.13 so it is used to buffer the pH. The quality of the city compost is not very good, and usually, I buy compost, the main ingredients are still “forest products”, but some of them have had chicken manure added and mushroom compost. I till in garden residues from clean plants as well.
I used to do more green composting of trenched kitchen waste, but I don’t have enough to count on it. Those, I use to feed the worm bin.
When your pH is alkaline, you can still use a starter N fertilizer or you can start your seeds since they contain all the nutrients they need to get them through till the leaves appear and begin side dressings of nitrogen at that time. However, timing is important and corn and other starter vegetables and fruiting plants need a lot of nitrogen to support early growth and fruit production, so I like to have some starter nitrogen. I usually do two side dressing of nitrogen with corn. Corn likes a pH between 5.5-7.0.