Survey of Soil Macronutrient Status on Vegetable Farms Around Keffi, Nasarawa State

This study surveys the macronutrient status of soils on vegetable production farms in the peri-urban area of Keffi, Nasarawa State, located in Nigeria's North Central geopolitical zone. Peri-urban vegetable production around Keffi is a rapidly expanding livelihood activity serving the Abuja-Keffi urban corridor, and the intensive nature of production with multiple cropping cycles per year raises questions about the sustainability of soil macronutrient balances under current management. Surface soil samples (0 to 20 cm) were collected from 30 active vegetable farms in three communities around Keffi metropolis. Samples were analysed for pH, organic carbon, total nitrogen, available phosphorus by Bray-1, exchangeable potassium, calcium, and magnesium, and cation exchange capacity. Farmer nutrient input records were reviewed to compare actual nutrient additions against crop export estimates. Findings revealed that 67 percent of surveyed farms had available potassium below critical thresholds for vegetables, while 53 percent had pH below 5.8, limiting calcium and magnesium availability. Phosphorus was elevated above 30 mg/kg in 45 percent of farms, reflecting over-application by farmers using compound fertilisers without yield-calibrated rates. Nitrogen was moderate in farms using poultry manure but below critical levels in farms relying solely on synthetic urea applied infrequently. The study recommends soil testing-guided fertiliser programmes, potassium supplementation for most farms, and lime application to correct acidity as priority management actions for Keffi peri-urban vegetable farms. Keywords: soil macronutrients, vegetable farms, Keffi, Nasarawa State, soil testing.