Effects of Mineral Fertilizers and Organic Manure Long-Term Application on Carbon Dioxide Emissions from Black Soils in Harbin, China
Carbon dioxide (CO2) is an important greenhouse gas. CO2emission from different long-term fertilized black soils was investigated by incubation experiment at soil water content of 70% water holding capacity. Maximal CO2flux was observed at the beginning of 24-h and 48-h incubation after the rewetting of dry soil. Combined fertilizer nitrogen (N), phosphorus (P) with manure (M) emitted the highest CO2-C, was up to 175 mg kg-1. Compared to zero fertilization (CK), fertilizers application increased CO2emission (P<0.05). Single fertilization N, P and potassium (K) increased CO2emission 19%, 43% and 22%, respectively. Combined two-way or three-way fertilizer N, P and K also increased CO2emission. Based on mineral fertilization, additional organic manure application furthered CO2emission. Two-way fertilizers (NP, NK and PK) application with organic manure increased CO2emission at the percentage of 398, 13.8 and 29.1, respectively (P<0.05). Although organic manure application ameliorated soil chemical, physical and biological conditions, organic manure fertilization increasing CO2emission should be considered in agricultural practice.