3.5 PCA and correlation study
The PCA comprising two principal components (PC 1 and PC 2) accounted for ~ 58% of the variation for the different fruit quality parameters, soil loss, and runoff with different treatments. An angle of 0 or 180° reflects a correlation of 1 or −1, respectively. The interpretation of PCA results can be described by the positioning of the different variables and superimposition of respective PCA plots for respective treatments as shown in the biplot (Fig. 7). The superimposition of individual plots for treatments on variables plot showed that intercropping of sapota with cowpea + castor on bench terrace and sapota alone on bench terrace represents a higher correlation with soil moisture, organic matter, organic carbon, available N, P, K, fruit weight, fruit moisture, vitamin C, tree growth, and antioxidants. The position of a total of 16 parameters of sapota, soil loss and runoff was influenced by various treatments. Similarly, correlation among various variables such as different sapota quality parameters, soil loss and runoff was presented in Fig. 8. All the variables showed a positive and significant correlation with each other except phenol, TSS (brix), TSS and runoff at p ≤ 0.05 (Fig. 8).