Characteristics and distribution pattern of carbon storage variation of the corn farmland ecosystem in the ecotone between agriculture and animal husbandry
Organic carbon storage and sequestration potential change in agricultural soils has been suggested to be an important issue in the study of terrestrial carbon cycling and global climatic change.To study the carbon storage and distribution pattern of corn farmland ecosystem at different stages (after plowing,seeding stage,maturity,before plowing in the next year) in the way of traditional deep-tillage operation and film-mulch planting,the local main crop,corn,was used to conduct the investigation in a typical ecotone between agriculture and animal husbandry in northern China.The result showed that the aboveground carbon storage was obviously higher than the belowground one.The change of soil carbon density was not evidently associated with the depth of soil layer.The average carbon rate of single maize was 43.3%.Except for root,leaf and stalk had higher organic carbon rate at seedling stage than that at maturity stage.And the carbon storage of single maize at maturity was more than that at seedling stage.The soil carbon densities in the corn farmland ecosystem at different stages were in the following order: maturity > seeding stage > before plowing in the next year > after plowing.Soil density after plowing was obviously decreased compared with other stages (P < 0.05).The changing law of soil carbon density was the same as the total carbon density of the corn farmland ecosystem.After a whole crop growing season,soil carbon density in the corn farmland ecosystem was increased by 13 415 kg·hm~(-2) more at the stage before plowing in the next year than that after plowing in the past year,reaching 10 974.8 kg·hm~(-2). Therefore,corn farmland ecosystem played an obvious role in fixing carbon and reducing discharge to atmosphere,allowing strong carbon sequestration capacity.