New Tools for Interpreting Foliar Nutrient Status Fertilization Working Group February 8, 2012

Operational fertilization decision-making l Forest level considerations l Stand level considerations  operational factors  biological factors species stand structure crown conditions insect/disease nutrient status

Foliar analysis as a planning tool l Foliar analysis can be used to:  confirm N deficiency

Foliar analysis as a planning tool l Foliar analysis can be used to:  confirm N deficiency  identify secondary nutrient deficiencies (e.g., S, B)

Foliar analysis as a planning tool l Foliar analysis can be used to:  confirm N deficiency  identify secondary nutrient deficiencies (e.g., S, B)  make appropriate fertilizer prescriptions

Foliar analysis as a planning tool l Foliar analysis can be used to:  confirm N deficiency  identify secondary nutrient deficiencies (e.g., S, B)  make appropriate fertilizer prescriptions  assess post-fertilization nutrient uptake and foliar nutrient balance

Foliar Sampling Protocol

l Sample during the dormant season

Seasonal change in foliar %N in Douglas-fir foliage May JuneJulyAugSeptOctNov Dec Moderate deficiency Month

Seasonal change in foliar %N in Douglas-fir foliage May JuneJulyAugSeptOctNov Dec Moderate deficiency Month

Foliar Sampling Protocol l Sample during the dormant season l Sample current year’s foliage

Foliar Sampling Protocol l Sample during the dormant season l Sample current year’s foliage l Collect foliage from between top 1/4 and bottom 1/2 of live crown

Foliar Sampling Protocol l Sample during the dormant season l Sample current year’s foliage l Collect foliage from between top 1/4 and bottom 1/2 of live crown l Collect foliage from healthy, representative trees

Foliar Sampling Protocol l Sample during the dormant season l Sample current year’s foliage l Collect foliage from between top 1/4 and bottom 1/2 of live crown l Collect foliage from representative trees l Collect foliage from at least 20 trees per stand or stratum

Foliar sampling layout x x x x x x x x x x x x x x x x x x x x Road Line 1 Line 2 /02 /01

Foliar Sampling Protocol l Sample during the dormant season l Sample current year’s foliage l Collect foliage from between top 1/4 and bottom 1/2 of live crown l Collect foliage from representative trees l Collect foliage from at least 20 trees per stand or stratum l For routine diagnoses, combine equal amounts of foliage from individual trees into one composite sample per stratum

Foliar Sampling Protocol l Sample during the dormant season l Sample current year’s foliage l Collect foliage from between top 1/4 and bottom 1/2 of live crown l Collect foliage from representative trees l Collect foliage from at least 20 trees per stand or stratum l For routine diagnoses, combine equal amounts of foliage from individual trees into one composite sample per stratum l Keep samples cool until foliage is dried

Factors affecting interpretation of foliar nutrient data

l Foliar sampling protocol

Factors affecting interpretation of foliar nutrient data l Foliar sampling protocol l Site ecological characteristics

from DeLong (2003)

Factors affecting interpretation of foliar nutrient data l Foliar sampling protocol l Site ecological characteristics l Laboratory analytical methodology

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

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

Accounting for differences in laboratory analytical methodology l Differences may be large enough to affect interpretation

Accounting for differences in laboratory analytical methodology l Differences may be large enough to affect interpretation l Nutrient interpretative criteria do not account for differences in methodology

Accounting for differences in laboratory analytical methodology l 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

Accounting for differences in laboratory analytical methodology l 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

Accounting for differences in laboratory analytical methodology l 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

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment

l 48 previously collected Pl foliage samples were selected

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l 48 previously analyzed Pl foliage samples were used l Samples were selected to cover a broad range of foliar nutrient levels

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l 48 previously analyzed Pl foliage samples were used l Samples were selected to cover a broad range of foliar nutrient levels l Each sample was thoroughly mixed and split into two sub-samples

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l 48 previously analyzed Pl foliage samples were used l Samples were selected to cover a broad range of foliar nutrient levels l Each sample was thoroughly mixed and split into two sub-samples l One sub-sample was shipped to each lab in December 2011

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l 48 previously analyzed Pl foliage samples were used l Samples were selected to cover a broad range of foliar nutrient levels l Each sample was thoroughly mixed and split into two sub-samples l One sub-sample was shipped to each lab in December 2011 l For each nutrient, laboratory results were reviewed and subjected to regression analysis

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l 48 previously analyzed Pl foliage samples were used l Samples were selected to cover a broad range of foliar nutrient levels l Each sample was thoroughly mixed and split into two sub-samples l One sub-sample was shipped to each lab in December 2011 l For each nutrient, laboratory results were reviewed and subjected to regression analysis l Based on previous research, equations were selected to “normalize” foliar nutrient data

Inter-laboratory comparison Pacific Soil Analysis vs. Ministry of Environment l 48 previously analyzed Pl foliage samples were used l Samples were selected to cover a broad range of foliar nutrient levels l Each sample was thoroughly mixed and split into two sub-samples l One sub-sample was shipped to each lab in December 2011 l For each nutrient, laboratory results were reviewed and subjected to regression analysis l Based on previous research, equations were selected to “normalize” foliar nutrient data l An Excel spreadsheet was developed to facilitate “normalization” for practitioners

Laboratory foliar N comparison PSAI vs. MoE

Laboratory foliar S comparison PSAI vs. MoE

Laboratory foliar SO 4 -S comparison PSAI vs. MoE

“Normalization” of laboratory foliar nutrient data

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

Normalization of laboratory foliar nutrient data

“Normalization” of laboratory foliar nutrient data

= 0.786x = 1.004x = 1.057x – 8.03 = 0.903x

“Normalization” of laboratory foliar nutrient data

Factors affecting interpretation of foliar nutrient data l Foliar sampling protocol l Site ecological characteristics l Laboratory analytical methodology l Availability of reliable foliar nutrient interpretative criteria

from Carter (1992)

from Brockley (2001)

Revised foliar nutrient interpretative criteria

Information sources: l Previously published interpretative criteria

Revised foliar nutrient interpretative criteria Information sources: l Previously published interpretative criteria l Published foliar nutrient and growth response data from Pinus, Picea and Pseudotsuga fertilization studies

Revised foliar nutrient interpretative criteria Information sources: l Previously published interpretative criteria l Published foliar nutrient and growth response data from Pinus, Picea and Pseudotsuga fertilization studies l Unpublished foliar nutrient and growth response data from BC fertilization studies

Revised foliar nutrient interpretative criteria Macronutrients

Revised foliar nutrient interpretative criteria Macronutrients cont’d

Revised foliar nutrient interpretative criteria Sulphate-S and Boron

Revised foliar nutrient interpretative criteria Nutrient ratios

Some basic interpretative rules

l Confirm that standardized foliar sampling protocol was used

Some basic interpretative rules l Confirm that standardized foliar sampling protocol was used l Assess foliar nutrient status within the context of site ecological characteristics

Some basic interpretative rules l Confirm that standardized foliar sampling protocol was used l Assess foliar nutrient status within the context of site ecological characteristics l Confirm that N deficiency exists before assessing other nutrients

Some basic interpretative rules l Confirm that standardized foliar sampling protocol was used l Assess foliar nutrient status within the context of site ecological characteristics l Confirm that N deficiency exists before assessing other nutrients l Assess S status in the following order of importance: SO 4 > N:S > S

Some basic interpretative rules l Confirm that standardized foliar sampling protocol was used l Assess foliar nutrient status within the context of site ecological characteristics l Confirm that N deficiency exists before assessing other nutrients l Assess S status in the following order of importance: SO 4 > N:S > S l N:P, N:K, and N:Mg ratios are more important than absolute levels of P, K, or Mg

Some basic interpretative rules l Confirm that standardized foliar sampling protocol was used l Assess foliar nutrient status within the context of site ecological characteristics l Confirm that N deficiency exists before assessing other nutrients l Assess S status in the following order of importance: SO 4 > N:S > S l N:P, N:K, and N:Mg ratios are more important than absolute levels of P, K, or Mg l Don’t be too concerned if possible deficiency is indicated for Cu, Zn, or Fe

Some basic interpretative rules l Confirm that standardized foliar sampling protocol was used l Assess foliar nutrient status within the context of site ecological characteristics l Confirm that N deficiency exists before assessing other nutrients l Assess S status in the following order of importance: SO 4 > N:S > S l N:P, N:K, and N:Mg ratios are more important than absolute levels of P, K, or Mg l Don’t be too concerned if possible deficiency is indicated for Cu, Zn, or Fe l Ask for help if uncertain