“Normalization” of Foliar Nutrient Data

l Differences in laboratory methodology may affect analytical results

Relationship between foliar N analytical methodologies dry combustion vs. wet digestion

Relationship between foliar S analytical methodologies dry combustion vs. wet digestion

“Normalization” of Foliar Nutrient Data l Differences in laboratory methodology may affect analytical results l Inter-laboratory differences may be large enough to affect interpretation

“Normalization” of Foliar Nutrient Data l Differences in laboratory methodology may affect analytical results l Inter-laboratory differences may be large enough to affect interpretation l Nutrient interpretative criteria do not account for differences in methodology

“Normalization” of Foliar Nutrient Data l Differences in laboratory methodology may affect analytical results l Inter-laboratory differences may be large enough to affect interpretation l Nutrient interpretative criteria do not account for differences in methodology l Known differences in laboratory analytical results can be used to “normalize” foliar data prior to interpretation

“Normalization” of Foliar Nutrient Data l Differences in laboratory methodology may affect analytical results l Inter-laboratory differences may be large enough to affect interpretation l Nutrient interpretative criteria do not account for differences in methodology l Known differences in laboratory analytical results can be used to “normalize” foliar data prior to interpretation l “Normalization” requires inter-laboratory comparisons

“Normalization” of Foliar Nutrient Data l Differences in laboratory methodology may affect analytical results l Inter-laboratory differences may be large enough to affect interpretation l Nutrient interpretative criteria do not account for differences in methodology l Known differences in laboratory analytical results can be used to “normalize” foliar data prior to interpretation l “Normalization” requires inter-laboratory comparisons l The “normalization” process does not make inferences about the quality of foliar nutrient data

Laboratory foliar N comparison (2012) PSAI vs. MoE

Laboratory foliar S comparison (2012) PSAI vs. MoE

“Normalization” spreadsheet (2012)

= 0.561x = 0.677x = 0.720x = 0.840x

“Normalization” spreadsheet (2012) = 0.786x = 1.004x = 1.057x – 8.03 = 0.903x

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l The 2012 inter-laboratory comparison was repeated in early 2013 following analytical equipment upgrade at the MoE lab

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l The 2012 inter-laboratory comparison was repeated in early 2013 following analytical equipment upgrade at the MoE lab l 50 previously analyzed foliage samples were used

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l The 2012 inter-laboratory comparison was repeated in early 2013 following analytical equipment upgrade at the MoE lab l 50 previously analyzed foliage samples were used l Samples were selected to cover a broader range of species and foliar nutrient levels than used in the 2012 comparison

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l The 2012 inter-laboratory comparison was repeated in early 2013 following analytical equipment upgrade at the MoE lab l 50 previously analyzed foliage samples were used l Samples were selected to cover a broader range of species and foliar nutrient levels than used in the 2012 comparison l Each sample was thoroughly mixed and split into two sub-samples

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l The 2012 inter-laboratory comparison was repeated in early 2013 following analytical equipment upgrade at the MoE lab l 50 previously analyzed foliage samples were used l Samples were selected to cover a broader range of species and foliar nutrient levels than used in the 2012 comparison l Each sample was thoroughly mixed and split into two sub-samples l One sub-sample was shipped to each lab

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l The 2012 inter-laboratory comparison was repeated in early 2013 following analytical equipment upgrade at the MoE lab l 50 previously analyzed foliage samples were used l Samples were selected to cover a broader range of species and foliar nutrient levels than used in the 2012 comparison l Each sample was thoroughly mixed and split into two sub-samples l One sub-sample was shipped to each lab l For each nutrient, laboratory results were subjected to regression analysis

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l The 2012 inter-laboratory comparison was repeated in early 2013 following analytical equipment upgrade at the MoE lab l 50 previously analyzed foliage samples were used l Samples were selected to cover a broader range of species and foliar nutrient levels than used in the 2012 comparison l Each sample was thoroughly mixed and split into two sub-samples l One sub-sample was shipped to each lab l For each nutrient, laboratory results were subjected to regression analysis l The new equations were used to revise the 2012 “normalization” spreadsheet

Laboratory foliar N comparison PSAI vs. MoE

Laboratory foliar S comparison PSAI vs. MoE

Laboratory foliar P comparison PSAI vs. MoE

Laboratory foliar K comparison PSAI vs. MoE

Laboratory foliar Ca comparison PSAI vs. MoE

Laboratory foliar Mg comparison PSAI vs. MoE

Laboratory foliar B comparison PSAI vs. MoE

“Normalization” of laboratory foliar nutrient data

= x = (0.3592x 2 ) + (0.7346x) = x = (0.1714x 2 ) + (0.8504x)

Normalization of laboratory foliar nutrient data

“Normalization” of laboratory foliar nutrient data

= x = (0.9558x) – (0.6267x 2 ) = (1.4164x) – (0.0008x 2 ) = (0.8732x) – (0.0012x 2 )

“Normalization” of laboratory foliar nutrient data