AGRIBIOMIX

Irrigation and fertilization of Paulownia

Paulownia Irrigation and Fertilization: Maximizing Yields

Good draining soil is the basis. But to achieve its growth objectives (3 to 5 m per year), Paulownia needs to be managed as an intensive crop. The difference between a stunted tree and a valuable log depends on access to water and a rigorous NPK fertilization plan.

Irrigation : Drip vs Gravity Fertilization plan: Nitrogen and Potash Input withdrawal schedule
The key principle: Paulownia is a “transformer”. It converts water and nitrogen into ultra-light wood. No fuel, no growth.

1. Water Management: Quantity and Frequency

Paulownia’s large leaves (optimized C4 photosynthesis) transpire enormously. Water stress is the primary factor limiting growth.

Le Goutte-à-Goutte (Recommended)

This is the queen of techniques. Unlike sprinkling, which encourages leaf diseases, drip irrigation brings water directly to the roots.

  • Year 1: 15 to 20 liters / tree / week (in 2 or 3 applications).
  • Year 2+: 30 to 50 litres/tree/week in dry periods.
Drainage alert: Never forget that water should not stagnate. If your soil is heavy, divide up the contributions (a little every day) rather than flooding once a week.

2. Fertilization plan: The Nitrogen-Potash Duo

Paulownia has similar needs to corn. It needs “food” to build up its biomass quickly.

Nitrogen (N)

The engine of growth.
Use in spring and early summer. Promotes leaf and green stem development. Source: Urea, ammonium nitrate or poultry droppings.

Potash (K)

Hardener.
Essential in late summer. It enables lignification (transformation of green wood into hardwood) and winter frost resistance.

Trace elements

Beware of Magnesium and Iron deficiencies (especially in calcareous soil pH > 7.5), visible by discoloration between the veins.

Service schedule (Technical Itinerary)

Timing is as important as quantity. Applying nitrogen too late prevents the tree from preparing for winter, increasing the risk of frost.

PeriodActionTargetProduct type
March – AprilStart irrigation (if dry)Root awakeningWater only
May – JuneNitrogen fertilization (N)Vegetative bloom (Height)N-rich fertilizer (e.g. 20-10-10)
July – August 15Maintenance + Irrigation maxMaintain rhythmN-P-K balance
End of AugustTOTAL nitrogen stopStop vertical growthPotash (K) alone
SeptemberIrrigation reductionControlled water stressStrengthens budding (lignification)
OctoberIrrigation stopDormancy
Why stop Nitrogen in August? If you push the tree to grow in September, the wood will remain green and tender (“herbaceous”). At the first frost in October/November, the top of the tree will freeze and you’ll lose 1 to 2 meters of marketable log.

Summary of unit requirements (Estimates)

Data to be adapted according to your initial soil analysis.

Display NPK units per hectare
annee,unites_N_ha,unites_P_ha,unites_K_ha,frequence_apport
annee_1,50-80,30-40,40-60,mensuel_mai_juillet
annee_2,100-150,50-60,80-100,mensuel_mai_juillet
annee_3_plus,150-200,60-80,100-120,fractionne_printemps
recommandation_eau,15-20L_semaine_plant,30-50L_semaine_arbre,,selon_pluviometrie

Technical FAQs

Can liquid manure be used?

Yes, it’s excellent, but be careful with burial. Manure must be well composted to avoid burning the young roots. Organic fertilization is best done in the autumn before planting.

Is irrigation compulsory?

For quality lumber production in 7-8 years: YES. Without irrigation, Paulownia survives but grows much more slowly (12-15 year cycles) and the wood will be denser, less homogeneous (irregular rings), which reduces its market value.

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