What approach could be used to determine if nitrogen availability in the soil directly limits the nutrient concentration of metrosideros polymorpha leaves?

adding of a known quantity of nitrogen to several experimental plots where the M. polymorpha is present.

Explanation:

In an experiment to determine nitrogen in the soil, different approach could be used, soil macronutrients samples could be chemically extracted then add with color base reagents, with theses the nutrient concentration that is in the soil samples l can be analysed. Using these method each nutrient that is present in the sample would be isolated into a solution then analysed through turbidity and color.

Other approach is the use of Metrosideros polymorpha leave which s a species of flowering evergreen tree that is part of the myrtle family, it Isa flowering plant and it's made up of stamens. This approach could be used to determine if nitrogen availability in the soil directly limits the nutrient concentration of metrosideros polymorpha leavesb by adding of a known quantity of nitrogen to several experimental plots where the M. polymorpha is present.