Fertilization

Objectives What factors affect fertilization decisions How to find information needed How to calculate application costs

Silvicultural Tools Plant Kill Ameliorate site

Ameliorate Site Irrigate Drain Subsoil Fertilize

What? How much? When? How?

The Details Fertilizer guide: uide/fert/ferttoc.htm Written in 1995 (Forest Code)

What Law of the minimum Law of compensation

Law of the Minimum Growth is limited by whatever factor is most need

Nitrogen Potential Growth Actual Growth

Law of Compensation The addition of one factor can increase the efficiency that a tree uses another factor

Law of Compensation With P Amount of N Growth Rate

How Much? Rule of efficacy What is needed Cost Returns

Rule of Efficacy Diminishing returns Growth Amount of “X”

Nutrient Cycling Availability CEC Weathering Mineralization C:N Nutrient capital Translocation

Fertilization Affects trees Does not affect site

Ratings Amount (percentage) of elemental Nitrogen (N); Phosphorous pentoxide (P 2 O 5 ); and Potassium oxide (K 2 O) Ex = 12%N; 20% (P 2 O 5 ); 10%(K 2 O)

Ratings 100kg would then have 12kg N; 20kg (P 2 O 5 ); 10kg (K 2 O) Atomic weights: N=14.01K=39.10 P=30.98O=16.0

Ratings (P 2 O 5 ) = (2 * 30.98) (2 * 30.98) + (5 * 16.0) or 43.65% P So 43.65% of 20kg = 8.7kg P

Analysis Soil Foliar

Effect Affects plants Does not affect site (response is shortlived) Affects stand dynamics

Target Species Non-trees can have more rapid uptake Can be detrimental (more competition)

When? Get above competition during establishment Increase diameter just before thinning or harvest Shorten rotation

How? “ Teabags” Sidecast Helicopter

Cost Application plus fertilizer How much will reach trees? Most effective on medium site indicies