I think I need more information. Corn needs full sun and a hot summer - does a \"fair crop\" mean you never get very good results? Is this year worse than fair? Every year are the stalks thin? It does sound like a fertility problem and corn is a \"heavy feeder\" which means you should fertilize in spring at planting time and then twice more during the growing season. Pale green leaves is the usual sign of not enough nutrients. Thin stalks could be a sign of a potassium deficiency. Is your soil acid? Do you live in an area of high rainfall? If so you might want to try adding lime or calcium carbonate to the soil in the fall and working this into the root zone. In the spring a complete plant food like Osmocote with all the micro and macro nutrients is like crop insurance. Then you can side dress the rows with compost or use a foliar spray on the young plants in July and again in August. Nothing like a corn roast in late summer to make all the gardening work pay off. Keep growing, Marianne Binetti