highly significantp < 0.01
Effects of Different N Levels and Green Manure Mixed Cropping Patterns on Wheat Yield Linear mixed-effects model (LMM) analysis of the two-year split-plot data revealed that N level had a highly significant main effect on wheat yield ( p < 0.01), as did green manure pattern ( p < 0.01), and their two-way interaction was also significant ( p < 0.01).