Assessment of soil fertility status and nutrient index in intensive vegetable growing belts

Abstract:

Intensive vegetable cultivation is quietly hollowing out the nutrient capital of Turkish soils. This research assessed soil fertility status and calculated the nutrient index for intensive vegetable growing belts in Antalya and Konya, covering 180 georeferenced sampling points collected between October 2022 and March 2024. Soils were analysed for pH, EC, organic carbon, available N, P, K, S and DTPA-extractable micronutrients (Zn, Fe, Cu, Mn, B). The nutrient index was worked out using the Parker scale. Results showed 67.2% of samples falling in the low-medium category for available N, 41.7% low in available P and 28.9% low in available K. Sulphur deficiency was found in 52.4% of sites, while zinc and iron were below the critical limit in 47.1% and 38.6% of samples respectively. Soil pH ranged between 6.4 and 8.6, with a clear inverse relationship (R² = 0.71) between pH and available P. Organic carbon averaged 0.41%, well below the 0.75% threshold considered safe for continuous intensive cropping. The nutrient index touched the 'very low' class for N in 38% of Antalya sites. Findings call for a targeted nutrient management plan built on site-specific soil testing rather than blanket recommendations.