Effects of Different Mulching Measures on Distribution of Organic Carbon and Inorganic Carbon in Soil Aggregates Under Spring Maize Cultivation

Abstract

[Objective] The effects of different mulching methods on the distribution of organic and inorganic carbon in soil aggregates on the Loess Plateau, and the mechanism under which soil aggregates sequester carbon under mulched conditions were determined in order to promote efficient management of dryland farm soil. [Methods] The study was conducted on a long-term positioning experiment beginning in 2012. Soil characteristics were studied from plots on which spring corn (“Xianyu 335”) was grown under three treatments: straw mulching (SM), film mulching (FM), and no mulching (CK). Carbon distribution and enzyme activities in aggregates of different particle sizes were determined by the wet sieve method. [Results] ① Organic carbon contents of aggregates of each particle size were significantly greater for SM than for CK (p2 mm in size, but significantly increased the reserves of aggregates 2 mm to 0.25 mm in size (p<0.05). ③ SM significantly increased the total carbon content of aggregates by 7.1% to 12.4%. Both FM and SM significantly increased the total carbon storage of particles ranging from 2 mm to 0.25 mm (p<0.05). ④ SM increased the activity of carbon cycling-related enzymes in aggregates, while FM decreased the activity compared with CK. Correlation analysis showed that there was a significant positive correlation between organic carbon and total carbon content and carbon cycling-related enzyme activities (p<0.05). [Conclusion] SM and FM significantly affected changes in the carbon pool of aggregates. SM was superior to FM in improving soil fertility and increasing soil carbon fixation.

Keywords

• spring maize
• straw mulching
• film mulching
• aggregates
• organic carbon
• inorganic carbon