"The Field" is a symbol of the nations among whom God's Predestination is fulfilled, the Promises are realized and the Will of God is evangelized by the righteous, and therefore "grows", the Good of moral and spiritual regeneration of the nations by their true understanding and fulfillment of His Commandments is born.
Negative meaning
"Field" - is a symbol of the people, which rejection, violation of God's Commandments "sprouted" thorns of moral decay, committing iniquity, plunged into a spiritual and desolate state, reaping, experiencing the consequences of their evil deeds.