Every time we remove crops from the field, we remove all of the plant nutrients. If the soil is short on available nutrients, either commercial or organic fertilizer must be applied to the field to maintain productive yields. But if the soil has a high supply of nutrients, soil testing is a must to avoid over-application, which may contribute to environmental problems. Ray Ward will discuss the essential nutrients plants need and the optimal soil test value of each nutrient. The founder and president of Ward Laboratories in Kearney, Neb., will also talk about the importance of returning animal manures to the fields at proper rates.