Integrated dairy manure management systems to simultaneously reduce environmental impact and improve fertilizing value

Summary

Animal manures contain crop essential nutrients like nitrogen and phosphorus and can help improve long term soil fertility. In intensive livestock production, specifically dairy cattle production, substantial amounts of manure is produced. Recycling this manure can thus reduce reliance on synthetic fertilizers. However, improper manure management -from excretion to soil application - leads to environmental pollution because of gaseous emissions and nutrients leaching and run-off. To tackle this, various technologies are in use in the different parts of the manure management chain. Yet, emissions remain high due to "pollution swapping," where reducing one pollutant leads to the increase of another in the same stage of the chain or later on. Recent research suggests that integrated management systems, starting with source segregation of faeces and urine and followed by complementary treatment and adapted soil application can simultaneously reduce environmental impact and improve the manure fertilizing value. This thesis focused on experimentally testing such integrated systems while providing insights into their mechanisms in the different part of the dairy manure management chain.