Evaluation on Soil Characterization in Paddy Treated with Different Green Manure Crops and Tillage Method by Ordination Technique

Abstract

Ordination has been recognized useful method to analyze the effects of multiple environmental factors on dozens of species in vegetation ecology because of summarizing community data by producing a low-dimensional graphics. Main objective of this study was the application of ordination method, especially principal components analysis (PCA), to analyze the soil characterization on paddy treated by different green manure crops and tillage methods. Treatments included the three tillage treatments and two green manure crops as the following; (ⅰ) moldrotary + rotary tillage without green manure crop (Con), with (ⅱ) hairy vetch (ConHv), and (ⅲ) hairy vetch + green barely (ConHvGb), (ⅳ) rotary tillage without green manure crop (Rot), with (ⅴ) hairy vetch (RotHv), and (ⅵ) hairy vetch + green barly (RotHvGb), and (ⅶ) no-tillage (Notill). Vectorial distance result from PCA of soil properties including physical, chemical, and microbial properties showed the two main difference. Firstly, soil properties among plots without green manure were strongly affected by tillage strength [Vectorial distance: Con-Notil (5.88) 〉Rot-Notill (4.58)] at PC1 (35.0%) axis. But it was difficult to find the fixed trend among plots when green manure crop was added in plot. Nevertheless, two groups were separated by adding green manure crop at PC2 (29.2%) axis. These results show that PCA ordination methods could be used the research for change of soil characterization.