Corn, potatoes, rice, and other crops will work. The first year might not make too much difference, but soils need to have nutrients put back after growing crops. You can decrease the amount of fertilizer you use by rotating crops and planting cover crops that restore nutrients. Commercial fertilizer can wash off fields into ponds and rivers, sometimes causing algae to grow and fish to die. Make sure you apply it correctly.
Many farmers spread manure on their fields.
Watch out for extra weeds from the seeds in the manure. You might have multicolored corn or other oddities. And your yield will probably be lower. You might not get all the seeds planted before it's time to harvest, but a huge crew could help. Most farmers use tractors and other machinery, which also means they use diesel fuel and oil, both of which can pollute the air and soil.