A study was conducted with Prunus x incamp ‘Okame’ to evaluate the effects of a pot-in-pot production system (PIP) compared to a conventional above-ground system (CAG) and cyclic irrigation on plant growth and water loss. Plants were grown in #7 (26 liter) containers with a pinebark: sand (8:1 by vol) substrate. Cyclic irrigation provided the same total volume of water, but was applied one, three, or four times per day. Final plant height and stem diameter, shoot and root dry weight, total biomass, and root:shoot ratio all increased for plants grown pot-in-pot compared to above-ground. Multiple irrigation cycles increased stem diameter, shoot dry weight and total biomass compared to a single irrigation application. Multiple irrigation cycles also decreased the root:shoot ratio. Mean daily water loss (plant transpiration + evaporative loss from the substrate) was influenced by production system, irrigation, and date. Mean daily water loss was 30% higher for pot-in-pot grown plants compared to above-ground. Cyclic irrigation resulted in a two-fold decrease in average leachate volume and a 27% increase in overall irrigation application efficiency compared to a single application. Production system had no affect on leachate volume or irrigation application efficiency. Substrate pH increased when cyclic irrigation was used. Production system and irrigation had no affect on soluble salts. Nitrate-N concentrations were less in the leachate of plants grown pot-in-pot compared to above-ground.
This research was supported by The Horticultural Research Institute, 1250 I Street, N.W., Suite 500, Washington DC 20005. Technical assistance of Bruce Tucker and statistical assistance of Ben Mullinix is appreciated. Donation of plants and supplies by Piedmont Growers, Graco Fertilizer Company, and The Lerio Corporation is gratefully acknowledged.