Influence of nitrogen fertilizer and compost mix application on greenhouse gas emissions from humid subtropical soils

Anuga Liyanage12, Peter R Grace1, David W Rowlings1   Clemens Scheer1

1 Institute for Future Environments, Queensland University of Technology, 2 George Street, Brisbane, QLD 4000, Australia.     [email protected] [email protected] [email protected]

2 Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya, 81100, Sri Lanka.

Abstract 

The application of organic amendments (OA) is a strategy to improve soil fertility and offset the high cost of mineral fertilizers used in agricultural systems. However, information on the interaction of OAs with synthetic fertilizers and the resulting greenhouse gas emissions from these combinations are not well understood for different soil types. A 36 day laboratory incubation experiment (3 compost x 3 N rates) was conducted to quantify soil N2O emissions along with CO2 and mineral N from subtropical soils in Gatton, Australia. Nitrous oxide emissions  decreased by 68% and 57% in  60N and 120N treatments respectively with the increase in compost applications  rates up to 30 t/ha and 60 t/ha. Adding 60 t/ha compost and 120 kg N/ha is considered  as the optimum fertilizer rate to minimize N2O and CO2 emissions from  a sub-tropical Vertosol and potentially conserving soil physical, chemical and biological properties for a sustainable crop growth.