Field Shield is a term used to describe a protective covering, such as a tarp, that is used to protect an outdoor area from the elements. A tarp is a large sheet of waterproof material that is used to cover an area, such as a field, to protect it from rain, wind, and other weather conditions. It can also be used to protect crops or livestock from the elements. Field Shield is a term used to describe the use of a tarp to protect an outdoor area from the elements.