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ETS Field Days 2015 - Copenhagen - Presentations
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OPTIMAL PLANT NUTRITION - FROM THE GREEN GRASS’ POINT OF VIEW
Agnar Kvalbein, researcher / consultant
ETS Field Day, Denmark
7th October 2015
1. THE OPTIMAL MIX OF NUTRIENTS
THE ROOT ZONE IN A GOLF GREEN IS MORE LIKE THE ARTIFICIAL
GROWTH MEDIA IN A GREENHOUSE THAN A NATURAL SOIL
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We know exactly which nutrients plants need from: • numerous experiments
(Ingestad et al.) • experiences from plant
production in greenhouses
• analyses of plant tissue
It is waste of resources to improve the fertility of the sand. Better to apply all the nutrients that the turf grass needs by spoon-feeding
Relative rates of nutrients in an optimal fertilizer(A),
and rates for diagnosis of nutirent deficciancy from leaf tissue (B)
Source: STERF web: Ericsson et al: Precision fertilisation – from theory to practice. See also: • MAGNUS F. KNECHT and ANDERS GÖRANSSON (2004) Terrestrial plants require
nutrients in similar proportions, Tree Physiology 24, 447-460
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Ericsson, T., & Ingestad, T. (1988). Nutrition and growth of birch seedlings at varied relative phosphorus addition rates. Physiologia Plantarum, 72, 227-235. Ericsson, T., & Kähr, M. (1993). Growth and nutrition of birch seedlings in relation to potassium supply rate. Trees, 7, 78-85. Ericsson, T., & Kähr, M. (1995). Growth and nutrition of birch seedlings at varied relative addition rates of magnesium. Tree Physiology, 15, 85-93. Ericsson, T., Rytter, L., & Vapaavuori, E. (1996). Physiology of carbon allocation in trees. Biomass and Bioenergy, 2, 115-127.
Göransson, A. (1993). Growth and nutrition of small Betula pendula plants at different relative addition rates of iron. Trees, 8, 32-38. Göransson, A. (1994). Growth and nutrition of small Betula pendula plants at different relative addition rates of manganese. Tree Physiology, 14, 375-388. Göransson, A. (1998). Steady state nutrition and growth responses of Betula pendula to different relative supply rates of cupper. Plant Cell and Environment, 21, 937-943. Göransson, A. (1999). Growth and nutrition of Betula pendula at different relative supply of zink. Tree Physiology, 19, 111-116
Some relevant references:
COMMENTS TO THE «IDEAL» FERTILIZER
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All numbers are related to the N level.
N is the minimum factor in this recipe and will
control the growth rate
The need for Ca is low. Most plants contain much
more than this. (“Luxury uptake” that cause
problems for plants with perennial leaves, like
Rhododendron)
Uptake of Mn (and Zn) is negatively related to soil pH, and
extra applications should be considered when pH is extreme.
Thompson, K et al. 1997: A comparative study of leaf nutrient concentrations in a regional herbaceous flora. New Phytol. 136, 679 – 689
SOME NUTRIENTS ARE MORE IMPORTANT THAN OTHERS
“The quantity and balance of fertilizers used on turf should be manipulated to obtain the most desirable playing surface. Any essential plant nutrient may control growth and development, but nitrogen is the most important…..”
Adams, W.A., P.J.Bryan, G.E.Walker (1974): Effects of cutting height and nitrogen nutrition on growth pattern of turfgrasses. Book: Proceedings of the Second International Turgrass Research Conference p 131 - 144
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You may find some texts and illustrations that give another message.
NUTRIENTS CAN BE GROUPED
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Reference:
Tom Ericsson (1995): Growth and shoot: root ratio of seedlings in relation to nutrient availability.
Plant and Soil, Volume 16, Issue 1, pp 205-214
N, P (and theoretically S) can be used to control plant growth. If P:N < 7:100, P will be the
minimum factor.
K, Mg, Fe and Mn are directly involved in photosynthesis, and
deficiency will lead to energy depletion and
reduced stress tolerance.
TAKE HOME MESSAGE 1
Be sure that K, Mg, Fe or Mn never is the «minimum factor» in your fertilization program.
The «ideal fertilizer» should be applied (all through the season) unless you have strong arguments for deviating from this recipe.
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2. GRASS SPECIES AND THEIR GROWTH POTENTIAL
PLANT GROWTH AND NITROGEN STATUS
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Growth
N concentration in leaves
Luxury uptake
poisoning
GRASS GROWTH CAPACITY AND NITROGEN STATUS
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Growth
N concentration in leaves 1 2 3 4 5 6
Max
Max
Ranking of the growth capacity of some common green-grasses
Art/sort Rankning
Poa annua 1.12*
Agrostis stolonifera ’Independence’ 1
Agrostis capillaris ’Barking’ 0.72
Agrostis canina ’Legendary’ 0.71
Festuca rubra ssp. commutata ’Center’ 0.55
Festuca rubra ssp. trichphylla ’Cezanne’ 0.33
* Plants transplanted from green. The other species were established from seed.
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Source: STERF web: Ericsson et al: Precision fertilisation – from theory to practice.
TAKE HOME MESSAGE 2
Find the fertilizer level that is adaped to the grass species that you grow.
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3. PLANT STRESS AND FERTILIZATION RATES
LOW MOWING REDUCES THE GRASS’ GROWTH CAPACITY.
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Growth
N concentration in leaves 1 2 3 4 5 6
Under optimal conditions, the uncut grass plant will be growth limited if the N content is 3.2% of the leaf dry matter.
Low cut reduces the growt capacity of the grass, and the low rate of N will not be experienced by the plant as the limiting factor.
Optimal N-level for green grass: 3-3.5 % of dry matter in the leaves
N-LIMITED GROWTH TO THE LEFT. N FOR MAX GROWTH TO THE RIGHT
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When the grass is cut low, there are no signs of N deficit because cutting reduces the plants’ growth capacity and
hence the need for N
LEAVES
ROOTS
N concentration
The root:shoot (R:S) growth is related to the N-status in the plant cells
Growth
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CARBON ALLOCATION AND N-RATES
Nitrogen
Relative root
growth
Content of
carbohydrates
Favourable conditions for growth
Unfavourable growth conditions
•Reduced leaf area •Low cutting •Leaf disease •Wear /damage
•Shade
•Too low temperature •Too high temperature
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Sugar
CO2
H2O
Greenkeepers are «carbohydrate managers». Plant stress can be defined as energy depletion. Sugar from photosynthesis is the only energy source for the plants
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Sugar
CO2
Sugar is used for all processes in the plants (flowering and seed production are not mentioned here). 1-4 in order of priority
1. Uptake and transport of nutrients and metabolites
2. Defence 3. Symbiosis 4. Root exudates
Respiration
H2O
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Sugar
CO2
Respiration
1. Uptake and transport of nutrients and metabolites
2. Defence 3. Symbiosis 4. Root exudates
Strongly related to N-level
Function of temperature
Dry matter production and root/shoot ratio
Growth and respiration are related to environmental factors. Greenkeepers can to some extent control the N-flow.
H2O
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Sugar CO2
Respiration
1. Uptake and transport of nutrients and metabolites
2. Defence 3. Symbiosis 4. Root exudates
Reduce N-level
Function of temperature
Shade
• Wind • Diffusion
from soil
• Low cut • Wear
• Drought • Dry spots • Shallow roots
• Compaction • Diseases • Oxygen depletion
Factors that reduce/influence on the plant’s growth capacity:
By controlling (reducing) the N-rate, the greenkeeper can avoid plant stress caused by unfavourable growth conditions and keep the plants alive
H2O
Finding the optimal ferilization rate is a delicate and difficult balance
Need for growth to compensate for wear & damage
Risk of energy shortage
N
TAKE HOME MESSAGE 3
Nitrogen is a strong tool for controlling growth.
It is dangerous to increase the fertilizer rate when the growth conditions are bad.
The weekly N-rates should be adapted the growth conditions. The most predictable are:
– light
– temperature
– mowing height
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AGNAR KVALBEIN
Phone: +47 40402089
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