2.5 | Statistical analysis
Data were subjected to analysis of variance (ANOVA) using the
windows-based SPSS program (SPSS v19.0).The impacts of tillage
management, straw management, and annual variation on SOC contents,
wheat grain yields, and maize grain yields were tested using three-way
ANOVAs. The effects of tillage and straw managements on plant-derived
biomass and carbon, SOC stock, yield variations of both wheat and maize,
and sustainable yield index of both wheat and maize were analyzed using
two-way ANOVAs. Multiple comparisons were made for determining
significant effects of treatments using the least significant difference
(LSD) test with P < 0.05. Simple correlation
coefficients and regression equations were developed to evaluate the
relationships between grain yields and SOC stocks.
3 |
RESULTS