Distribution of carbon, nitrogen, phosphorus, and sulfur in the soil in a multiple habitat system in India

We measured the background level and spatial variation of carbon ( C), nitrogen (N), phosphorus ( P), and sulfur ( S) and associated basic soil parameters along the depth pro. le for 3 years, in 3 habitats ( woodland, wetland, and grassland), in Keoladeo National Park (KNP), an important water fowl reserve and a world heritage site in India. The study examined soils at 5 depths ( 0, 0.25, 0.50, 0.75 and 1.0 m) for 3 years, i.e. from 2003 to 2005. Total organic C (TOC), total N (TN), total available P ( TAP), and total available S (TAS), irrespective of the habitat type and year, were found to be highest in the litter layer, gradually declining with depth. Elemental ratios ( C : N, C : P, and C : S) followed the same declining trend, whereas the N: P ratio increased down the soil pro. le. The high C : N and C : S ratios in the litter layer suggest the relatively low mobilisation of N and S from the decaying detritus layer. All the variables studied varied significantly among the soil layers (GLM-ANOVA, P < 0.05). Principal component analysis (PCA) showed 4 components based on examination of the scree plot. The first component accounted for 27.1% of the total variance in soil characteristics among samples, reflecting the influence of soil variables such as P, TOC, and pH. The second component accounted for 23.5% of the total variance, reflecting the influence of total dissolved solids (TDS) and TAS. The influence of C on elemental ratio ( C : S) was pointed by the third component, accounted for 14.2% of the total variance. The fourth component accounted for 13.6% of the variance, indicating the influence of soil TN. Thus, the 4 PCA components that accounted for 78.4% of the total variance in the data can be qualified as N:P/soilP/C, TDS/TAS, C : S ratio, and soil TN, respectively.