Effects of Conservation Tillage on Organic Carbon and Carbon Management Index in Paddy Soil

Abstract

Effects of different tillage systems on organic carbon and carbon management index (CMI) in paddy soil of long-term experiment site (since 1990) were studied. The experiment included three tillage treatments: conventional tillage with rotation of rice and winter fallow (CT-r) system, no-tillage and ridge culture with rotation of rice and rape (RT-rr) system, and conventional tillage with rotation of rice and rape (CT-rr) system. Soil labile organic carbon measured by oxidation of KMnO4 respond rapidly to carbon supply changes, and it is considered as an important indicator of soil quality. Compared with CT-r system, long-term RT-rr system significantly increased total organic carbon and labile organic carbon in surface soil (0-10 cm and10-20 cm). The proportion of labile organic carbon to total organic carbon under RT-rr system was higher than other tillage systems. The carbon management index (CMI) is derived from the total soil organic carbon pool and carbon lability and is useful to evaluate the capacity of management systems to promote soil quality. The CMI increased in each layer under RT-rr system, while it decreased under CT-rr system. This indicated that conservation tillage improved the capacity of the management system into promoting soil quality in Sichuan Basin of China.

Soil nitrogen and carbon storages and carbon pool management index under sustainable conservation tillage strategy

“…Compared with CT, no tillage and straw mulching can increase soil carbon storage, especially the combination of the straw with no tillage is the most significant; Zhang et al (2015) noted that conservation tillage increased the content of organic carbon and TN in the upper soil, had no significant effect on the deep soil, and did not increase the storage of carbon and nitrogen in the soil profile during field experiment of the double cropping system of winter wheat and corn in Beijing, China. Peng et al (2011) recorded in the study of rice cultivation in Sichuan basin that compared with traditional rotation, no tillage ridge cultivation can significantly increase the surface soil organic carbon and active carbon. Under no tillage ridge cultivation, the soil CPMI is improved, nonetheless it is reduced under traditional rotation, and conservation tillage improves the quality of rice soil.…”