Short-term contributions of cover crop surface residue return to soil carbon and nitrogen contents in temperate Australia.
Cover crop species are usually grown to control weeds. After cover crop harvest, crop residue is applied on the ground to improve soil fertility and crop productivity. Little information is available about quantifying the contributions of cover crop application to soil total carbon (C) and nitrogen (N) contents in temperate Australia. Here, we selected eight cover crop treatments, including two legume crops (vetch and field pea), four non-legume crops (rye, wheat, Saia oat, and Indian mustard), a mixture of rye and vetch, and a nil-crop control in temperate Australia to calculate the contributions of cover crops (crop growth + residue decomposition) to soil C and N contents. Cover crops were sown in May 2009 (autumn). After harvest, the crop residue was placed on the soil surface in October 2009. Soil and crop samples were collected in October 2009 after harvest and in May 2010 after 8 months of residue decomposition. We examined cover crop residue biomass, soil and crop total C and N contents, and soil microbial biomass C and N contents. The results showed that cover crop application increased the mean soil total C by 187-253 kg ha-1and the mean soil total N by 16.3-19.1 kg ha-1relative to the nil-crop treatment, except for the mixture treatment, which had similar total C and N contents to the nil-crop control. Cover crop application increased the mean soil microbial biomass C by 15.5-20.9 kg ha-1and the mean soil microbial biomass N by 4.5-10.2 kg ha-1. We calculated the apparent percentage of soil total C derived from cover crop residue C losses and found that legume crops accounted for 10.6-13.9 %, whereas non-legume crops accounted for 16.4-18.4 % except for the mixture treatment (0.2 %). Overall, short-term cover crop application increased soil total C and N contents and microbial biomass C and N contents, which might help reduce N fertilizer use and improve sustainable agricultural development.
Environmental Futures Research Institute and Griffith School of Environment, Griffith University, Nathan, 4111, Australia. xqzhou@des.ecnu.edu.cn.|Center for Global Change and Ecological Forecasting, Tiantong National Forest Ecosystem Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, 200241, China. xqzhou@des.ecnu.edu.cn.
Xiaoqi
X
Zhou
NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Pine Gully Road, Wagga Wagga, NSW, 2650, Australia.
Hanwen
H
Wu
NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Pine Gully Road, Wagga Wagga, NSW, 2650, Australia.
Guangdi
G
Li
Environmental Futures Research Institute and Griffith School of Environment, Griffith University, Nathan, 4111, Australia. c.chen@griffith.edu.au.
Chengrong
C
Chen
D000383:Agriculture / Q000379:methods; D001315:Australia; D018533:Biomass; D002244:Carbon / Q000032:analysis*; D018556:Crops, Agricultural / Q000254:growth & development; D007887:Fabaceae / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis*; D012987:Soil / Q000737:chemistry*
D012987:Soil; D002244:Carbon; D009584:Nitrogen
Cover crops; Microbial biomass C; Microbial biomass N; Soil total C; Soil total N