In 1990, advancements in sustainable manure management for pig farming began to emerge, focusing on treating pig manure for biogas and fertilizer production. These innovations aimed to reduce the environmental impact of livestock farming by minimizing waste and promoting renewable energy sources. The shift towards sustainable practices has been crucial in addressing the challenges of agricultural pollution and resource management.

Sustainable manure management in pig farming in 1990 became a focal point in eco-literature, with poets like Gary Snyder and Wendell Berry promoting circular economies. Their works emphasized the interconnectedness of agriculture and environmental stewardship.