A 2026 study published in the Kirkuk University Journal for Agricultural Sciences examined how irrigation intervals and mulching treatments affect young Paulownia tomentosa saplings under semi-arid conditions in the Kurdistan Region of Iraq — conditions similar to many regions where our partners plan plantations.
What the experiment tested
Researchers grew 36 saplings under three irrigation intervals (every 3, 6, or 9 days) combined with three mulching treatments (no mulch, hay mulch, black plastic film), tracking height, stem diameter, leaf number, biomass, nutrient uptake and physiological responses.
Key findings
- Irrigation frequency dominated early growth. Saplings watered every 3 days reached about 128 cm in height and 23 mm in stem diameter, with the most leaves. Irrigation every 9 days produced the weakest growth regardless of mulching.
- Hay mulch + frequent irrigation produced the greatest dry biomass — over 630 g per plant across all parts.
- Mulch type shifted nutrient uptake: hay mulch improved nitrogen uptake, while black plastic mulch enhanced potassium absorption.
- Water-use efficiency was highest under the 9-day interval with black plastic — relevant where water is scarce and some growth must be traded for efficiency.
Practical takeaways for plantation managers
The study confirms what our field experience in Shaanxi has long shown: the establishment year is decided by water. For new plantations:
- Keep irrigation frequent during the first growing season — especially in the first 60–90 days after planting;
- Use organic mulch (hay/straw) where soil fertility is low; use plastic mulch where water conservation is the priority;
- Match the watering schedule to soil texture — sandy soils need shorter intervals than clay loams;
- Measure, don't guess: simple soil-moisture checks prevent both drought stress and waterlogging, which paulownia dislikes.
Every site is different. Our guided fertilization and irrigation programs translate findings like these into a schedule that fits your soil, climate and water supply.
Sources & Further reading
- Influence of Irrigation Intervals and Mulching Treatments on Paulownia tomentosa Saplings (Kirkuk University Journal for Agricultural Sciences)
- DOI: 10.58928/ku26.17112
Want an irrigation and fertilization plan for your site? Email paulownia@vip.126.com.