Abdul Wahab Khan
Panaji
Despite years of mining, deforestation, soil erosion and rapid development across the ecologically sensitive Western Ghats, Goa’s forest soil continues to show generally good fertility, although scientists have warned that site-specific management is essential to safeguard the fragile ecosystems.
That is the key finding of a new study published in the Journal of the Indian Society of Remote Sensing by researchers Durai Muniammal Vediappan, Abhishek Godi and Basavaraj Golla, all affiliated with the Indian Council of Agricultural Research–Central Coastal Agricultural Research Institute (ICAR-CCARI), Goa.
The analysis revealed that Goa’s forest soils are predominantly acidic, with an average pH of 6.31, while electrical conductivity remained within the neutral range. Average available nitrogen measured 299.25 kg/ha, phosphorus 37.62 kg/ha and potassium 264.51 kg/ha.
The team documented significant variability in sulphur and micronutrient concentrations across different forest landscapes, highlighting that soil fertility is far from uniform.
One of the study’s most significant findings was the complex relationship among soil nutrients. Soil pH showed a strong positive correlation with organic carbon, phosphorus, potassium, zinc, iron and boron, while soil organic carbon was positively associated with nitrogen and several micronutrients.
According to the study authors, these relationships provide valuable insight into nutrient cycling within Goa’s forest ecosystems and can guide precision nutrient management.
The researchers identified six principal components explaining 74.46 per cent of the total variability in soil characteristics before classifying Goa’s forests into three nutrient management zones using fuzzy clustering techniques.
“The results indicate that soil fertility of Goa’s forests is good, based on the average values of the soil parameters of developed MZs,” the study has said.
The team added that “the study’s findings can be effectively utilised by forest managers and policymakers to improve forest soil fertility, refine precision silviculture management and advance afforestation initiatives.”
The researchers cautioned that although fertility remains generally favourable, continued soil acidification, nutrient depletion and erosion caused by human activities could gradually undermine forest health if left unmanaged.
They recommended regular geospatial monitoring of soil nutrients, adoption of site-specific nutrient management rather than uniform interventions, and greater use of precision forestry tools to improve afforestation, restore degraded landscapes and strengthen ecological resilience in Goa’s forests.
The researchers undertook the study because increasing anthropogenic pressures, including mining, industrialisation, urbanisation and deforestation, have accelerated topsoil erosion and nutrient depletion in Goa, threatening ecological security and long-term forest productivity.
As the paper has noted, the objective was “to delineate management zones to safeguard the integrity of the forest soil ecosystem and to spatially differentiate the soil qualities within forested regions.”
To achieve this, the team collected 36 georeferenced surface soil samples from four major forest types across Goa using stratified random sampling on a 5×5-km grid. Fourteen soil properties were analysed, including pH, electrical conductivity, soil organic carbon, available nitrogen, phosphorus and potassium, exchangeable calcium and magnesium, sulphur, and micronutrients such as zinc, copper, iron, manganese and boron.
The researchers combined laboratory analysis with geostatistical modelling, ordinary kriging interpolation, principal component analysis and fuzzy k-means clustering to generate high-resolution nutrient maps and delineate soil management zones.
