Figure 2
From: Effect of straw and inhibitors on the fate of nitrogen applied to paddy soil
Structural equation model analysis for the contribution of urea-N to soil total nitrogen retention. The numbers on the arrows are normalized path coefficients. The thickness of the arrow is proportional to the size of the path coefficient. Continuous arrows and dotted arrows indicate positive and negative correlations, respectively. Asterisks after data indicates a significant difference (*P < 0.05, **P < 0.01, *** P < 0.001). U: 15N labeled urea; US: 15N labeled urea + straw; UI: 15N labeled urea + inhibitor; UIS: 15N labeled urea + inhibitor + straw. FA stands for fixed ammonium derived from urea; MBN stands for microbial biomass nitrogen derived from urea. DON represents soluble organic nitrogen derived from urea; TN represents total nitrogen derived from urea sources; NH4+-N denotes ammonium nitrogen derived from urea. TDN represent total dissolvable nitrogen derived from urea. Some variables have no arrows because in the operation of maximum likelihood number method, the route with relatively small path coefficient is removed in order to make the model more fit and more in line with the fitting index described below in the figure.
