PCA based index to measure the soil fertility status of panchayats in Pathanamthitta district, Kerala

Abstract

Soil fertility is an indication of productivity of soil, which can be assessed with the help of available soil nutrient parameters. Assessment of soil fertility of the regions facilitates better fertilizer recommendations for each region separately. However, since the availability of soil nutrient parameters vary from region to region, assessment of soil fertility based on an index comprising of soil nutrient parameters may be preferred. In this context an attempt was made in this paper to construct a single value Soil Fertility Index (SFI) of 50 panchayats in Pathanamthitta district in Kerala, using 12 soil nutrient parameters namely, pH, EC, OC, P, K, Ca, Mg, S, B, Cu, Fe and Mn. Principal Component Analysis transform the original variables to orthogonal linear combinations by providing weights to each variable and was performed here initially to determine weights of 12 soil nutrient parameters and four principal components which accounted for around 68 per cent variation in the soil nutrient data were retained. The weighted aggregation of four principal component scores with weight as share of variance of each component was considered as the SFI. The estimated SFI of 50 panchayats varied from 46. 99 (Thottapuzhaserry panchayat) to 248.48 (Aruvappulam panchayat) with 33.49 per cent coefficient of variation. Further the index was normalized and the panchayats were grouped into low (SFI from 0%-25%), medium (25%-50%), high (50%-75%) and very high (75%-100%) fertile based on normalized index.