Microbial Community Structure of Paddy Soil Under Long-term Fertilizer Treatment Using Phospholipid Fatty Acid (PLFA) Analysis

Abstract

Understanding the microbial community structure of agricultural soils is important for better soil managementin order to improve soil quality. Phospholipid fatty acid analysis has been popularly used in determining themicrobial community structure in different ecosystems. The microbial community structure of paddy soilunder long-term fertilizer treatments was investigated after 45 years using PLFA analysis. Treatments werecontrol (no fertilization, Con), compost (COM), NPK, NPK+compost (NPKC), PK, NK, and NP. Soilchemical properties were mainly affected by the addition of compost and inorganic P fertilizer. Total nitrogenand organic matter contents were significantly higher in treatments with compost while available P2O5 andexchangeable calcium were significantly higher in treatments with added inorganic P fertilizer. It was foundthat microbial communities were responsive to the different fertilizer treatments. PLFA results showed that thesoils were dominated by gram-negative bacteria, followed by the actinomycetes, then gram-positive bacteria,and fungi. Principal component analysis of the soil chemical properties and PLFA composition proved to be amore reliable tool because it was more responsive to the changes in soil chemical properties.