Shemitta affects not only society's social, political and economic structure, it also affects society's ideological base.
The same impulse that forces the society to create enough surplus to feed the nation during the sabbatical year also serves to induce the society to build the institutional infra-structure to create that surplus. Along with the abundance of that surplus comes the self-respect for having built the institutional infra-structure, and along with the building of the infra-structure comes the orientation toward the future and the habit of stewardship that makes for a proper creative ideological ground. That ideological ground is what the society needs in order to take care of the land not only during the fallow years but also during the six productive years.
It's not for nothing the instructions of the Bible focus on environmental stewardship. The spiritual teachings of the Bible incline the people into a comprehensive concordance with the natural order, where the spiritual integrates with the material.
To implement those teachings requires the people to achieve a proper measure of abundance. When abundance and a concern for the environment work hand in hand they form the basis for a right-minded ideological ground for people to cultivate a good society.