PARENT SESSION
Poster Session 39: Late Breaking and Newsworthy Posters
Friday, August 12, 8:30 AM - 10:30 AM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Change of organic carbon content and its fractions in agricultural ecosystem with recycled nutrition.
Han, Xiaozeng*,1, Wang, Shouyu1, 1 North-east Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, Harbin, Heilongjiang Province, China
ABSTRACT- A long-term experiment was conducted in northeast China to study the effect of chemical fertilizers and recycled organic manure on the contents of organic carbon and its fractions of black soil (0-20cm depth). Eight treatment were used: 1) Control; 2) Recycled organic manure (ROM); 3) Nitrogen alone; 4) N + ROM; 5) N + P; 6) N + P + ROM; 7) N + P + K; and 8) N + P + K + ROM. The results showed that comparing 1985 with 2002, soil total organic carbon (TOC) decreased by 6.5% over the 18 years in control (33.25 g/kg in 1985), 5.6% in ROM treatment, 5.1% in N alone treatment, 1.5% in the N + P treatment, but increased by 0.3% in the N + P + K treatment, and in the three treatments of chemical fertilizers together with ROM (i.e., N + ROM, N + P + ROM, and N + P + K + ROM), TOC content in 2002 increased by 0.3%, 1.3% and 2.8%, respectively when compared with control in 1985. Compared with control in 2002, light fraction organic carbon (LFOC) content increased by 23% in N + ROM treatment, 24% in N + P + ROM and 28% in N + P + K + ROM; and readily oxidized carbon (ROC) content increased by 24%, 31% and 39% respectively in these three treatments. The ROC was well correlated with soil TOC. Compared with the data 18 years ago, in all 8 treatments organic carbon of soil in humic acid decreased in the range of 5.0-13%, and in fulvic acid decreased in the range of 1.4-14%, however, with chemical fertilizers and ROM applied together, the rate of decrease was reduced. Overall, ROM is useful for increasing the content of organic carbon and its different active carbon fractions in black soil, thus, would help to maintain or increase soil productivity.
Key words: Black soil, Agricultural ecosystem, Soil organic matter, Chemical fertilizer