Articles
EVAPOTRANSPIRATION AND DRY MATTER PRODUCTION OF HORTICULTURAL CROPS UNDER COVER
Pekinensis), beet (Beta vulgaris L.) and spinach (Spinaca oleracea L.) grown under cover and open air.
Covered plants were covered by spunbonded film soon after being sown or transplanted.
Crops were drip irrigated.
ET was calculated by a water budget that considered applied irrigation water and rainfall as inputs, and the variations in soil moisture (
) as output.
The neutron probe and TDR were used to measure soil moisture content, respectively, at depth and in the upper 20 cm of soil.
Crop growth was assessed by measuring crop biomass and leaf area index at regular intervals (approximately every 15 days). Crop water-use efficiency was calculated as biomass produced per unit of ET.
Crop ET, above ground biomass and crop water use efficiency were generally similar in both treatments for the three species in both years.
Plants grown under cover generally had higher LAI and therefore higher specific leaf area.
In beet, tuber dry weight was higher under cover, increasing crop yield.
Enhanced leaf area development under cover compensated for the lower evaporative demand (lower net radiation, smaller vapour pressure deficits and no wind) giving similar ET values under cover and in open air.