Embed Size (px)
DESCRIPTION
Course about the growth of strawberries on substrate
Citation preview
© DLV Plant
Fertilisation and Dripping in Softfruit
on substrates
Wim Roosen
12 March 2008
2/5© DLV Plant
Program of today:
1. The role of water in plants
2. Strategy of dripping and feeding
3. What is EC and pH?
Deficiency of elements
© DLV Plant
1. The role of water in plants
4/5© DLV Plant
The role of water in plants
Water uptake (average):
• 1 % Fotosynthesis
• 9 % Growing
• 90 % Transpiration
5/5© DLV Plant
The role of water in plants
Fotosynthesis
• H20 + CO2 + Light ���� C6H12O6 + O2
6/5© DLV Plant
The role of water in plants
Growing = Cell splitting + Cell stretching
Cell stretching:
Water + fertilizers + sugars
7/5© DLV Plant
The role of water in plants
Transpiration:
- Water transport
- Feed transport
- To cool leafs
8/5© DLV Plant
Transpiration
9/5© DLV Plant
Leaf under microscoop
10/5© DLV Plant
Stomata
11/5© DLV Plant
Regulation of the stomata
• Licht gives stimulation:
H+ out and K+ in � OPEN
• CO2 low: Cl- channel blocked
� OPEN
• CO2 high: Cl-channel open -K+ out� CLOSED
• Waterstress: Cl-channel openK+ out� CLOSED
• Forced K+ uptake � swelling(by osmosis) � OPEN
12/5© DLV Plant
Transpiration
Open/close of stomata depends on:
- Light/Hormonal
- Amount of water in the leafs
- Humidity in the air around
- CO2-amount (ppm) in the air
- Salts K/Cl
Important to know for GH: fotorespiration =
Plants makes his own CO2 in case of low CO2-
concentration in the air! Costs a lot of energy.
13/5© DLV Plant
Transpiration
Stomata not good open = negativ for:
- No optimal growing – especially to non transpirating
parts of the plants, as ……..
- Transpiration is cooling
↑ plant temperature = ↑ energy loss by respiration
- uptake CO2 (fotosynthesis)
H2O + CO2 + Licht = C6H12O6 + O2 giving …….
less sugars, less growing, less quality, less yield
14/5© DLV Plant
Transpiration
How can we stimulate the transpiration on stomata level?
- enough light
- well feed level & balance in subtstrates – in plant
- supply of enough water: transpired + run off
- RH control (humidity)
» Outdoor: sprinkle if hot/dry
» Tunnel: vent enough, not too much & on right time
» GH: same, heat (min pipe)
- Apply CO2 up to 1000-1200 ppm or max. 20 gr/m2/hr
Closed GH or tunnel CO2 down to 250 ppm
15/5© DLV Plant
Water supply by the roots
The uptake of feed by the roots is an osmotic process:
Sugars in the plant and salt concentrations around the roots
give an attraction to water.
Water transport in the plant further by osmotic forces and
rootpressure.
Rootpressure at the end of the day when air temperature goes
down and RH goes up:
» Transpiration reduces/stops
» Root activity still there
16/5© DLV Plant
Root activity
Root activity depends on:
- Substrate-EC
- Moist of substrate
- Quality of the roots
- Substrate/roottemperature
- Level of transpiration – RH/HD
- Radiation
17/5© DLV Plant
Rootpressure:
- More uptake than transpired → capitation
- Quick changing increases the root pressure.
- 1 moment per day = positive (few hours end of day)
- Spreading of Calcium to not transpirating parts
(new trusses and leafs) to avoid tipburn.
- Spreading assimilates to parts with no or few
chloroplasts (fruits, roots, seeds)
18/5© DLV Plant
Rootpressure:
- Long time = negative
- Cells collapse & die by O2 deficiency
growing points die, brown stolons, petioles
- Wet plants leads to Rhizoctonia, Botrytis, etc.
- In combination with many sugars/assimilates:
brown, wet, glue fruits = lost or misshape
19/5© DLV Plant
RH on day high:
• Disturbing water transport
• Appearing of fungis (Botrytis, etc.)
• Weak growing (loosing speed, earliness)
• Weak fruit (loosing quality, firmness)
• Tipburn (loosing LAI – leaf area)
Solution: reduce RH by
�Venting
�Heating
�Air movement (fans in GH, doors open tunnels)
�Cool the GH (new developments now in Holland)
20/5© DLV Plant
How to increase rootpressure?
- (Quick) drop down RH
- Decrease of EC
- Create good moist during the day & night.
- Good root/substrate temperature
- Good radiation (for strong roots)
Actions?
21/5© DLV Plant
How to increase rootpressure?
• (Quick) drop down RH
• Decrease of EC
• Create good moist during the day & night.
• Good root/substrate temperature
• Good radiation (for strong roots)
Actions?
Vent, EC decrease on radiation (on comp), never dry
coir, heat if possible, clean glass, new plastic, ……
22/5© DLV Plant
How to avoid/decrease rootpressure?
- Stimulate transpiration = get out of humidity in tunnels/GH
- Increase of EC gives less easy water uptake
- Less drips, less run off, EC goes up.
Let struggle the plant to get water.
- Decrease temperature of substrate/roots: reduces activity.
23/5© DLV Plant
Not enough root activity
When the transpiration is getting too much the plant
protects himself by closing the stomata
→ less transpiration → RH down around leaf →further closing of the stomata, CO2 by respiration
Gives a (large) increase of plant temperature, and a
decrease till complete stop of growing processes (=
stress).
Plants start to use energy (burning sugars):
- Size of fruit drops, growing stops
- Quality decrease: pink, albinsm
24/5© DLV Plant
Actions to do:
→ Create a transpiring plant as plants are cooling machines- get the plants used to regularly low RH on the day
(that gives the power to …………..)
- strong and working roots (EC-decrease, dripping)
→ Cool down the plastic/glass: roof sprinklers→ If RH < 55-60%: - overhead sprinklers (inside)
- air humifying systems
→ Climate steering: less vent on wind side and decrease tolee side as well. Better temp a bit higher and better RH +
CO2 levels.
25/5© DLV Plant
Relative Humidity:
• Optimum RH during growing 70-75%
• During flowering/pollunation: 60-70%
• While harvest: around 70%
• At night: > 85% (rootpressure)
© DLV Plant
2. Strategy dripping and feeding
27/5© DLV Plant
Drippers to discuss
• CNL
• PCJ
• French capillair
28/5© DLV Plant
Strategy dripping and feeding
Always a steering to a certain EC/moist level that the plants
do need at that moment and the week after:
WaterEC-FeedStage / Needs of
Growing
Flowering
Harvest
Rooting
29/5© DLV Plant
Dripping EC and pH
Crops on coir, except blues is a mix
5,62,7-2,91,3-1,51,3-1,51,2-1,5Everest
1,2-1,5
2,5-3,0
2,0-2,5
1,6-1,8
Run off
4,52,0-2,50,9-1,21,1-1,5Blues
5,64,5-5,52,0-2,52,0-3,3Blacks
5,64,0-5,01,7-2,52,0-3,0Rasps
5,63,0-3,21,4-1,71,2-2,0Elsanta
pHSum ECHarvest Growing EC
30/5© DLV Plant
Dripping
Around planting strawberries:
• Before planting substrates moist is preferred.
• Coir to wet up with EC 1,3
Shower/flush after planting:
• To clean the leafs (sand and dirt delays)
• To contact roots to substrate
• To avoid dry places around the roots
• To get feed in (in case of coir) EC 1,3
31/5© DLV Plant
Dripping
Start dripping after planting strawberries:
• Keep the whole substrate (espec. bags - corners) at
good moist level. WET probe 50-60%. FEEL!
• Peat: no feed added on fertilized peat + bare root
plants during first week. Trayplants EC 1,0-1,2
• Coir: start with trays/misted tips at EC 1,3-1,4
• When rooting goes on: increase EC - slow/fast?
• Only in Winter time: few drips a week EC 2,5 on wet
bags to get some feed in.
32/5© DLV Plant
Dripping
Growing stage Elsanta
• Increase drip EC 1,5-1,7
• Get run off to EC 1,5-1,6 as an always minimum for all crops.
• Drain-%:
0-5 % when less activity
10-20% when good growing
33/5© DLV Plant
Dripping
Flower and green fruit stage Elsanta
• Drain-EC to build up to 1,7-2,0
• Drain % 10-15 % when less activity
25-30 % when good growing
• From 1 week before harvests starts:
decrease EC to 1,7 till 1,4 when hot ta avoid high EC
• During picking: run off EC 1,7-1,8 target
• What to do if EC run off = 3,0?
• ……..
• ……..
34/5© DLV Plant
Dripping
Not only the % of run off counts!
- Drip times: 2,5 – 3 minutes on strawberries
- Amounts of drips
- Stage of crop
- Radiation, radsum
- Wind & RH
- Start and stop times on sunny weather…..
and on cloudy weather…..
- Moment that run off falls: AM, PM, night?
35/5© DLV Plant
Dripping – how much?!
The substrate may never be dry on the root-ends:
- Drip as much as needed! FEEL!
- The equipment needs to be reliable and enough
capacity to give up to 3 drips x 3 minutes per hour
- In Winter Elsanta / Tulameen to double crop:
- pH goes down � drip pH 6,0 from October
- EC goes up as plants do not use much �
EC 1,0-1,2 to drip (“only acid”)
36/5© DLV Plant
Water usage table top Elsanta
• Crop full grown and fully loaded fruit
• 30ºC
• RV 50%
• Wind: 7 m/s
• Run off included
Water usage outdoor: up till 8 liter/m2/day!
With 4 drippers/mtr (400 ml drip): 25 drips/day
Water usage tunnels: up till 6 ltr/m2/day!
Around 20 drips/day.
37/5© DLV Plant
EC-decrease
When there is much transpiration by heavy sun:
- less need to feed, water!
- to avoid accumulation of salts
EC-decrease on the day, f.i. EC1,8 – 0,3:
- from 10.30 en 15.30 hr (when long distances)
- on radiation also possible on short distances, but the
traject W/m2 needs regular adjustments!
38/5© DLV Plant
Start en stop times
• Too wet substrate at night gives too low oxigen in the
substrate � leads to weak and dying roots
• But: a loaded crop with ripening fruits needs to stay on
rootpressure for size and taste and to avoid.
So avoid dry moments at night and early morning!
• Growing and flowering stage to drip 1-2 hours before sun
set.
• From white fruit stage drip till around sun set
• And spread well the drips over the day:
39/5© DLV Plant
Spread the drips over the day:
1 drip 11
2 ,, 10-13
4 ,, 9-11-13-15
8 ,, 8-10-11.30-13-14-15-16-17.30 (average)
12 ,, 7-8.30-10-11-12-13-14-15-16-17.30-19.30
16 ,, 7-8-9-10-11-11.45-12.30-13-13.30-14-14.30-15.15-
16-17-18.30-20
20 ,, 6-7-8-9-10-10.45-11.30-12-12.30-13-13.20-13.40-
14-14.30-15-16-17-18-19.30-21
40/5© DLV Plant
GOLDEN RULE IN DRIPPING:
IF THE 1st DRIP IN THE MORNING GAVE RUN OFF THEN:
………..……………………...
1. First drip was too early or
2. Previous day 1 drip too less given
WE WANT RUN OFF JUST STARTING DURING THE 2ND
DRIP IN THE MORNING
41/5© DLV Plant
Run off control
Drain collection:
• check drain EC en pH
• check amount of drainwater
• minimum 1 draincollection per valve
• check run off moments over the day
Every drip needs some run off: 2-5-10-20-30%, so not
the last drip giving 90%....... pumping up your %.
42/5© DLV Plant
Why run off?
• Moistening whole volume of substrate
• Compensates differences in drippers, plants, volume
• Even balance in feed elements, close to recipe
• To flush out salts as sodium and chlorides, and so to avoid accumulation of these
• Too much run off:
• decrease of oxigen – weak roots etc.
• loss of fertilizers, gras growing too fast…
• increases degeneration in case of peat
43/5© DLV Plant
Run off collection point
© DLV Plant
3a. What is EC and pH?
3b. Deficiency of elements
45/5© DLV Plant
Feed elements
• Macro-elements
• N, P, K, Mg, Ca, and S
• Micro-elements
• Fe, Mn, Zn, B, Cu, Mo
• Passive or active uptake by the roots
• Antagonism with active uptake
• Mobile (N+, K+, Mg2+)
Immobile elements (Ca2+, Mg2+, PO4, SO4)
46/5© DLV Plant
Ions uptake
• Uptake of the ions by the roots is regulated by
exchange: f.i. K+ <> H+ or NO3 <> OH
• Uptake positive ions: pH drops
• Uptake negative ions: pH goes up
• Plants prefer single-loaded ion (K, NO3)
Good balanced recipes in each stage of crop!
• What is important to know to make a good recipe?
• The basic water contents: rain, river, mains,
borehole, salty water (to coast)
47/5© DLV Plant
Elemental Chemistry
• Atom (f.i. N, O, H)
• Molecule (Bijv. CaCl, H2O, CaNO3)
• Ion = electrical loaded element pos + or neg -
2+/3+/4+ or 2-/3-/4-
• Calcium (Ca2+) + Nitrate (NO3-) � Ca(NO3)2
ion + ion = fertilizer
• Calciumnitrate = 14,5% N-NO3
1,0% N-NH4
19,0% CaO
48/5© DLV Plant
EC in mS/cm
• Only ions are taken (exchanged) by the roots
• Ions in water give a conductivity.
More ions in water give more conductivity.
Ions do differ in conduction: 3+ more than 1+
• Electrical Conductivity = EC in mS/cm
• Does high run off EC mean high NO3?
• Concentration: more salts � higher EC
• Water: less water/dry �………….
• Temperature: warmer gives more EC
49/5© DLV Plant
Crop, growth and EC
• Optimum EC for strawberries = LOW compared to
other crops.
• Strawberries are salt-sensitiv crops!
Drip EC 1,3 - 2,0 and blackberries EC 1,5 - 3,5
What does that mean? (think on the basic water)
• Low EC: easy possible deficiency
• High EC: bad rooting, less growth, poor yield, size
& quality
50/5© DLV Plant
pH
• pH = concentration of free H+ ions
• Most crops pH 5,5-6,0 is optimum = just a few H+
• Mmol/liter – the more H+ � the lower pH
pH4 = 10x more acid as pH5 = 10x more acid as pH6
• Acids available: nitric, phosphoric, sulphuric
• What happens when we add acid to bicarbonate?
• HNO3 + HCO3-� H20 + CO2 + NO3
• Hard water = much Ca and HCO3 (takes time to react)
We need the recipes to calculate well: Ca & NO3
51/5© DLV Plant
pH tabel
• Optimum pH 5,5-6,0
• Too low: roots die
• 1st problem high pH:
– Manganese (leaf)
– Iron (add Eddha - red)
– Boron (flowers!)
• EC up � pH down A/B
• EC low � pH control OK?
• Pre acid water pH 6,0
contains NO3
52/5© DLV Plant
Sampling, what?
• Substrate: give long term (some weeks) average
To check the recipe + water adjustments.
Feed can be perfect, but dripped wrong gives poor crop.
To Holland / BLGG in case of doubts.
• Leafs: gives ……. Good levels on bad crop possible.
Yellow leafs: wrong recipe, high pH, forgotten in tanks.
• Run off: only when dripping enough > 20% run off very actual situation = short term. Adjust every 2 weeks.
• Dripwater: to test the whole system. Try it.
53/5© DLV Plant
Nitrogen deficiency
54/5© DLV Plant
Deficiency to Phosphorus
55/5© DLV Plant
Deficiency to Potassium
56/5© DLV Plant
Deficiency to Calcium - tipburn
57/5© DLV Plant
Deficiency to Magnesium
58/5© DLV Plant
Deficiency to Sulphur
59/5© DLV Plant
Deficiency to Iron – high pH
60/5© DLV Plant
Deficiency to Manganese
61/5© DLV Plant
Deficiency to Boron - flowers
62/5© DLV Plant
Too much Boron – black
63/5© DLV Plant
Deficiency of Zinc
64/5© DLV Plant
Deficiency of Molybden
65/5© DLV Plant
Salt damage
66/5© DLV Plant
Albino fruit
67/5© DLV Plant
Where does the coir come from?
• Palmae of Arecaceae
• Cocos nucifera
• 30 mtr high, - 6 mtr leaves
• Big industry: oil-shampoo, milk-
pina colada, jewelery, bounty,
fibres (drainpipes, door-mats,
carpets)
• “dust” was left….. till some
Dutchmen saw it in 1990.
68/5© DLV Plant
Thanks for your attention
Questions?
