Agronomy is the study of how to grow crops well — not only putting seeds in the ground, but soil, water, weather, and how plants stay healthy so farms can feed people. An agronomist is the person trained in this. Farmers do the growing; agronomy is the science sitting behind that work, asking which seed, which fertilizer, which way of planting will actually help. You will meet it in universities and farm reports more than in everyday talk. People sometimes say agriculture when they mean this, though actually agriculture is the whole business of farming, animals included, and agronomy is more narrowly the crop side and the science of it.