Publication Date:
2009-11-01
Description:
In order to study how soil carbon and nitrogen contents of different aggregate size fractions are affected by an increase in crop biomass and additional carbon inputs to soil due to elevated [CO2], a field experiment under a free-air CO2 enrichment (FACE) system was conducted. The experiment was set up with two CO2 levels [ambient CO2 and elevated CO2 (ambient + 200 ?mol mol-1)] and three N levels [low N (LN), 150 kg N ha-1 and 90 kg N ha-1, normal N (NN), 250 kg N ha-1 and 180 kg N ha-1, and high N (HN), 350 kg N ha-1 and 250 kg N ha-1, during the rice season and the wheat season, respectively] and straw was added at the same soil:biomass ratio as in the field during the rice and wheat seasons. Compared with ambient CO2, little change was observed in the percentage distribution of soil fractions, carbon and nitrogen content, and C:N ratio in each soil fraction under elevated CO2 from 2001 to 2003. However, after the soil was cultivated with straw at two CO2 levels, as a ratio of biomass to field area for 1 yr, elevated CO2 decreased the percentage distribution of the macroaggregate (〉 250 µm) and microaggregate (53-250 µm) fractions by 28.9% (P
Print ISSN:
0008-4271
Electronic ISSN:
1918-1841
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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