1 Nutrition and Fertilization Profit vs. Professionalism Jerry Bond
2 Overview General Nutrition Fertilization Challenges Resources
3 General Nutrient = essential element Required by plant to complete its life cycle (growth and reproduction) Irreplaceable by another mineral element Directly involved in plant metabolism, or required for a distinct metabolic step
4 General Macronutrients need lots ( Mickey Mouse ) CHO NPK SCaMg Middle group is typically limiting Third group: sort of mesonutrients Micronutrients need little (ppm), but still need! Fe, Mn, B (palms) Mo, Cl, Co, Cu, Zn rarely for ornamental
5 General Need Timing depends on nutrient function N used during growth Uptake Bulk flow (e.g., N) Osmosis (e.g., Ca) Active uptake (e.g., Fe or Mn) Biotic actions (e.g., chelation)
6 General Symbioses Fungi mycorrhizae Bacteria legumes Actinomycetes olive family All trade C for P Additional poss. benefits Antifungal, antibacterial Water uptake Ecto- or Endo-?
7 General Sources Basic materials = rock, soil, air External biotic recycling = breakdown of OM in soil Internal recycling = strong incentive over evolutionary time Anthropogenic = human additions to soil, water and air HUH?! Alex Shigo
8 Nutrition Primary concerns Reasonable growth for species and age Reasonable profit for industry Management goals Older: sufficient maintenance respiration Younger: sufficient growth respiration
9 General Growth promotion factors in order of importance Light Water Air (soil) OM ph Human additions Trees: low nutrient specialists
10 Nutrition Light, water and soil air Top 3 growth promoters Priority over nutrition per se Liebig's Law (and his Barrel) Growth is controlled not by the total amount of resources available, but by the scarcest resource (=limiting factor).
11 Nutrition Macronutrients On most soils, N is only limiting macronutrient for ornamental trees 2 Research: 1-2 lb of N per 1000 ft probably enough for most purposes Apply in slow-release form (WIN at least 50%) early fall or early spring Lower salt index is better Research: best use young tree fertilization
13 Nutrition Need varies by species, climate, soil Fast-growing vs. slow-growing Single vs. episodic flush Climate Growing season Precipitation Trouble soil types Clay: high CEC, H2O, bulk density, ph Sand: low CEC, H20, bulk density, ph
16 Nutrition Micronutrients Fe most common in urban: e.g., pin oak, dogwood, grey birch, white pine Mn next: e.g., red maple, white oak B for palms Usually enough in soil, but at least one chemical form is insoluble Fe+2 - e- Fe+3
17 Nutrition Micro remediation difficult OM: many methods supported Drainage: often alleviates Elemental sulfur (+ quick acidifier) Short-term: A chelate drench (e.g., FeEDDHA), if available (not Mn) Trunk injection (=in tree's best interest?)
18 Nutrition Evergreens (ornamental) Most narrow-leafed are adapted to low-nutrient Most broad-leafed require OM and low ph Light, water and ph usually control growth Usually need no fertilization, which can attract pests (e.g., aphids) Pinus strobus
19 Fertilization ANSI A300 Fertilization Standards: Reason Supply nutrients determined to be deficient to achieve a clearly defined objective. That objective should be accomplished in the manner most beneficial to the plant." Manner "Fertilizer should be applied so that nutrients are available when roots are growing." Type "Slow-release fertilizers should be the preferred type."
21 Fertilization Defined but unacceptable? Make money What we always do Give the tree a boost Defined but acceptable? Promote young tree development Stimulate root growth after disturbance Balance N demand from fresh OM
22 Diagnosis Field Shoot extension Investigate < 2 average Many other factors Chlorophyll estimation Munsell color system Minolta Chlorophyll meter Phone apps (ColorMeter, SmartSPAD*) *co-dev. Amy Kaleita, ISU
23 Color/vigor vs. N in valley oak Vigor & color group % total foliar N 1 (best) (worst) 2.3 Source: Perry/Hickman 1998
25 Diagnosis Lab Soil test Poor for N (except loss by ignigtion for OM) False reading for micros Recommendations agricultural Only tells what is in the soil, not in the plant Foliar analysis Tells exactly what got into the plant Often expensive ($25) and slow (3 weeks)
26 Diagnosis Species Populus deltoides Range % foliar N Acer saccharum Quercus alba Source: Mills/Jones 1996
28 Fertilization Soil additives Adding mycorrhizae usually unnecessary Compost tea (high quality) Research supports general approach Convenient way to feed the soil Bio-stimulants/Root stimulants Many products and ingredients Independent research does not support (Watson/Heimlich 2013) Confounding factors: OM, water, air Mostly marketing, e.g. pea gravel, dried molasses, perlite, worm castings, lava sand and compost
29 Challenges Focus on nonpoint source chemical fertilizer contamination of the state's rural and urban water resources. (State of Minnesota) Phosphorous (crops, lawn) Threat to inland water Maryland, Long Island, Michigan (1994, 2006, 2015) Nitrogen (crops, lawns) Threat to coastal water Less commonly regulated New Jersey
30 Challenges The Georgia Phosphorus (P) Index is a tool to assess the risk of bioavailable P loss from grasslands and cropped fields to surface waters. Loss of bioavailable P to surface waters is of concern because it can accelerate eutrophication in lakes and streams of the state.
31 Challenges Minn Dep Ag
33 Conclusion Professionals would do well to have an answer for the 3 basic questions from the A300: How was a deficiency determined? What is the treatment objective? How is the treatment in the best interests of the plant? Your ability to answer these questions from a client is what defines you as a professional.