Articles
EFFECT OF PLANTING DENSITY ON DRY-MATTER PRODUCTION AND EVAPOTRANSPIRATION OF TULIPS
In 1970, a lysimeter installation of 15 units was constructed in a beach bank soil with different constant ground-water levels.
Inflow and outflow were registered continuously, and soil moisture content was measured periodically by gamma-ray attenuation.
In 1970, tulips of the cultivar "Merry Widow" were planted at distances of 8×8, 11×11 and 15×15 cm at 5 different ground-water levels per treatment, ranging between 40 and 100 cm below the soil surface.
The rate of net photosynthesis was measured by periodic harvesting on 7 dates as well as by dry-matter distribution and leaf area.
In other lysimeter units total bulb production and total dry-matter production were measured at normal lifting time, and the soil cover, crop height and degree of senescence were determined several times before lifting.
No effects of soil-water management on production were seen, but a close correlation was found between measured and computed dry-matter production.
Evapotranspiration per plant decreased with increasing density, but increased per unit of soil area.
Data on the course of transpiration during the day and growing period are given.