Location: Agricultural Systems ResearchTitle: Soil carbon fractions in response to straw mulching in the Loess Plateau of China
|WANG, JU - Northwest University|
|FU, XIN - Northwest University|
|FAZHU, ZHAO - Northwest University|
Submitted to: Biology and Fertility of Soils
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2018
Publication Date: 3/8/2018
Citation: Wang, J., Fu, X., Sainju, U.M., Fazhu, Z. 2018. Soil carbon fractions in response to straw mulching in the Loess Plateau of China. Biology and Fertility of Soils. 10:ply020. https://doi.org/10.1093/aobpla/ply02.
Interpretive Summary: Straw mulching during the growing season enriches soil health but reduces wheat yield. Straw mulching is usually done to conserve soil water and sustain dryland crop yields in China, but its effect on soil health is not known. An ARS researcher in Sidney, MT in collaboration with scientists from Northwest University, Xian, China studied the effect of straw mulching during the winter wheat growing season and the summer fallow period on soil carbon sequestration and microbial biomass and activity as well as wheat yield from 2009 to 2017. Straw mulching during the growing season increased C sequestration and microbial biomass and activity but reduced wheat yield compared with mulching during the fallow period or no mulching. Additional nitrogen fertilizer may be required to enhance soil health and wheat yield when straw mulching is done during the growing season. Soil microbial activity is a good measure of soil health and wheat yield.
Technical Abstract: Straw mulching has been used to conserve soil water and sustain dryland crop yields, but the impact of the quantity and time of mulching on soil C fractions is not well documented. We studied the effects of wheat straw mulching on soil C fractions at 0-10 and 10-20 cm depths and winter wheat yield from 2009 to 2017 in the Loess Plateau of China. Treatments were no mulching (CK), wheat straw mulching at 9.0 Mg ha-1 (HSM) and 4.5 Mg ha-1 (LSM) during the winter wheat growing season (LSM), and wheat straw mulching at 9.0 Mg ha-1 during the summer fallow period (FSM). Soil C fractions were soil organic carbon (SOC), particulate organic carbon (POC), microbial biomass C (MBC), and potential C mineralization (PCM). The SOC, POC, PCM, and MBC at 0-10 and 10-20 cm depths were 8-27% greater with HSM and LSM than FSM and CK. At 0-10 cm, SOC and POC increased from 0.09 and 0.07 Mg C ha-1 with CK to 0.40 and 0.30 Mg C ha-1 with LSM, respectively, from 2009 to 2017. Winter wheat grain yield was 12-14% greater with CK and FSM than HSM and LSM, but total aboveground biomass was 4-6% greater with HSM than CK and FSM in most years. The PCM at 0-10 and 0-20 cm was correlated with wheat grain yield and all C fractions at most depths were correlated with the estimated wheat root residue returned to the soil. Wheat straw mulching during the growing season increased soil C sequestration and microbial biomass and activity compared with mulching during the fallow period or no mulching, but reduced wheat grain yield, regardless of mulching rate. Additional N fertilization may be needed to enhance wheat yield and soil health when mulch was applied during the growing season. The PCM is a good indicator of soil health and wheat yield compared with other C fractions.