The present study aimed to determine the variation in calcium (Ca), magnesium (Mg), and potassium (K), which are crucial macronutrients for plants, in soil and plant organs at a copper mining site. In the study, the soil was sampled from various soil depths in the spoil field, the rehabilitation site in which planting was carried out and adult trees were present, and the forest area. Furthermore, bark, leaf, root, and wood samples were taken from black pine (Pinus nigra Arnold.), scots (Pinus silvestris L.), and black locust (Robinia pseudoacacia L.) species growing in the rehabilitation and forest areas. The work determined general variation in the concentrations of elements in soils and organs according to the plant species, and variation in element concentrations depending on the soil depth was statistically significant only in Ca. However, the determined element concentrations were quite high. In line with the average values, the variation in Mg in plants was not statistically significant, while the highest Ca and K concentrations were obtained from Robinia pseudoacacia species.

Field experiments were carried out during the dry seasons in (2012-2013 and 2013-2014) to study the impact of Integrated Nutrient Management on some soil properties and nutrients uptake by red onion (Allium cepa L.) in Moda, Michika, Adamawa state, Nigeria. Soil samples were randomly collected and analysed for pH, EC, organic carbon, organic matter, total nitrogen, available phosphorus before and at the completion of the experiment. Total nitrogen, phosphorus and potassium contents of the onion bulbs were determined. There was an improvement in the fertility status of the soil as a consequence of integrated nutrient management. Combined organic and inorganic fertilizer application influenced the uptake of nitrogen, phosphorus and potassium by red onion. The highest nitrogen, phosphorous and potassium uptake by onions of 0.76, 43.82 and 2.42kgha-1 occurred when all treatments were combined. Uptake of N and K increased as treatment level increased. The P uptake was highest at lower treatment levels and could be linked to sufficiency of indigenous soil P for plant growth resulting in high P uptake with minimal addition of nutrient inputs. Integrated Nutrient Management could be adopted to improve soil fertility status and N, P and K uptake by red onions.

Field experiments were carried out during the dry seasons in (2012-2013 and 2013-2014) to study the impact of Integrated Nutrient Management on some soil properties and nutrients uptake by red onion (Allium cepa L.) in Moda, Michika, Adamawa state, Nigeria. Soil samples were randomly collected and analysed for pH, EC, organic carbon, organic matter, total nitrogen, available phosphorus before and at the completion of the experiment. Total nitrogen, phosphorus and potassium contents of the onion bulbs were determined. There was an improvement in the fertility status of the soil as a consequence of integrated nutrient management. Combined organic and inorganic fertilizer application influenced the uptake of nitrogen, phosphorus and potassium by red onion. The highest nitrogen, phosphorous and potassium uptake by onions of 0.76, 43.82 and 2.42kgha-1 occurred when all treatments were combined. Uptake of N and K increased as treatment level increased. The P uptake was highest at lower treatment levels and could be linked to sufficiency of indigenous soil P for plant growth resulting in high P uptake with minimal addition of nutrient inputs. Integrated Nutrient Management could be adopted to improve soil fertility status and N, P and K uptake by red onions.