Response of organic carbon mineralization of paddy soil with different planting years to temperature in loess area of central of Northern Shaanxi Province
To explore the response of organic carbon mineralization in paddy soil with different planting years to temperature,the rice field soil samples with different planting years(3,30,78 a)were collected at the Nanni-wan Rice Planting Base in the typical loess hilly and gully regions of Northern Shaanxi Province.The characteristics and differences of organic carbon mineralization were measured through indoor 35-day cultivation experiments and mineralization dynamic models between paddy and dry land soils.Temperature changes had a significant impact on organic carbon mineralization.The main results were as follows:the cumulative mineralization amount and minerali-zation rate of soil organic carbon under different tillage years were shown as 78 a paddy soil＞30 a paddy soil＞3 a paddy soil＞maize soil.The cumulative mineralization amount,mineralization rate,potential mineralizable organic carbon content(C0)and the ratio of potential mineralizable organic carbon to SOC(C0/SOC)were shown as 30℃＞20℃＞10℃.The accumulation of organic carbon mineralization in paddy soil showed a significant decrease at 10C(2 015.14 mg·kg-1)compared to 20℃(2 799.20 mg·kg-1)and 30℃(3 078.47 mg·kg-1)(P＜0.05),but there was no significant difference between 20℃ and 30℃.The accumulated mineralization amount of organic carbon in the 0～20 cm soil layer was 1.18 times that in the 20～40 cm soil layer.The temperature coefficient(Q10)was higher under temperature increased from 10℃ to 20℃(Q10 value was 1.38)when relative to the temperature increased from 20℃ to 30℃(Q10 value was 1.14),and the order of Q10 values under different layers as follows:0～20 cm＞20～40 cm.The potential mineralizable organic carbon content C0 had a significant positive correlation with TOC,easily oxidized organic carbon and dissolved organic carbon.The relationship between C0 and microbial bio-mass carbon indicated a positive correlation,but not reached a significant level.C0/SOC decreased with the im-prove of rice planting years,indicating that the soil organic carbon sequestration capacity be enhanced with the rice planting years.
paddy soilplanting yearsorganic carbon mineralizationtemperature changescentral of Northren Shaanxi Province
万方数据
维普
