# Spectrophotometric Determination of Biopolymers in Alabama Benchmark Soils
## 3 Results
### Relationships between Cellulose, AB Lignin, ACE Protein, and Soil Properties  
The correlation coefficients between biopolymers and soil properties are shown in Table 3. From Pearson correlation coefficients, cellulose and lignin showed a strong positive correlation with each other and with SOM, SOC, TN, and CEC, and a strong negative correlation with soil-available phosphorus (SAP). While lignin was negatively correlated with C:N ratio, it was positively correlated with protein, SOC, TN, POxC, PMN, CEC, EA, pH, and EC, although not significantly. Cellulose positively correlated with soil organic matter, soil organic carbon, total nitrogen, soil-available phosphorus, cation exchange capacity, pH, potentially mineralizable nitrogen, and electrical conductivity. Cellulose was negatively correlated with soil-available phosphorus and C:N. While soil protein showed a positive correlation with lignin, cellulose, SOM, SOC, TN, POxC, PMN, EA, and EC, only the relationship with EA was significant. A weak negative correlation was observed between soil ACE protein and C:N ratio, ECEC, and pH, and no relationship with soil SAP. A robust simple linear regression analysis showed that SC was significantly related to CEC (r\({}^{2}\) = 0.455, \(p\) = 0.046), TN (r\({}^{2}\) = 0.461, \(p\) = 0.044), SOM (r\({}^{2}\) = 0.507, \(p\) = 0.031), and SAP (r\({}^{2}\) = 0.713, \(p\) = 0.004). An increase in soil lignin corresponded to a significant increase in SOM (r\({}^{2}\) = 0.494, \(p\) = 0.035), and a decrease in SAP (r\({}^{2}\) = 0.53, \(p\) = 0.026). Protein was not significantly correlated with soil properties except extractable acidity (r\({}^{2}\) = 0.0.695, \(p\) = 0.005). It was noted that the strength of the relationship between soil chemical properties and soil cellulose, lignin, and protein content is highly dependent on soil pH. When acidic soils only were considered, cellulose, lignin, and protein showed a stronger relationship with soil properties, as shown by the heat maps (Figure 5). It was observed that cellulose, lignin, and protein were significantly related to SOM, SOC, TN, PMN, ECEC, and EA, and the relationships between lignin and PMN and SAP were observed to be significant. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline  & **Lignin** & **Cellulose** & **Protein** & **SOM** & **SOC** & **TN** & **CN** & **POxC** & **PMN** & **SAP** & **ECEC** & **CEC** & **EA** & **pH** & **EC** \\ \hline Lignin & 1 & 0.775 \({}^{\star}\) & 0.444 & 0.703 \({}^{\star}\) & 0.613 & 0.588 & \(-\)0.134 & 0.235 & 0.494 & \(-\)0.728 \({}^{\star}\) & 0.603 & 0.628 & 0.161 & 0.487 & 0.114 \\ Cellulose & 0.775 \({}^{\star}\) & 1 & 0.393 & 0.712 \({}^{\star}\) & 0.682 \({}^{\star}\) & 0.678 \({}^{\star}\) & \(-\)0.186 & \(-\)0.00 & 0.399 & \(-\)0.844 \({}^{\star}\) & 0.656 & 0.675 \({}^{\star}\) & 0.048 \({}^{\star}\) & 0.746 \({}^{\star}\) & 0.402 \\ Proteins & 0.444 & 0.393 & 1 & 0.388 & 0.189 & 0.318 & 0.305 & 0.300 & 0.451 & \(-\)0.006 & \(-\)0.137 & \(-\)0.058 & 0.849 \({}^{\star}\) & \(-\)0.279 & 0.407 \\ SOM & 0.703 \({}^{\star}\) & 0.712 \({}^{\star}\) & 0.388 & 1 & 0.967 \({}^{\star}\) & 0.932 \({}^{\star}\) & \(-\)0.089 & 0.336 & 0.812 \({}^{\star}\) & \(-\)0.625 & 0.828 \({}^{\star}\) & 0.872 \({}^{\star}\) & 0.404 & 0.499 & 0.366 \\ SOC & 0.613 & 0.682 \({}^{\star}\) & 0.189 & 0.967 \({}^{\star}\) & 1 & 0.879 \({}^{\star}\) & 0.082 & 0.261 & 0.706 \({}^{\star}\) & \(-\)0.615 & 0.916 \({}^{\star}\) & 0.946 \({}^{\star}\) & 0.226 & 0.611 & 0.401 \\ \hline \end{tabular}
\end{table}