International Water & Irrigation

45 (two irrigations per day) using five mM N (Figure. 2B) . Daily water use. On two of the three measurement dates, plant DWUwas seen to be affected by the interaction between N rate and container type. On the first measurement, the greatest DWU results came from biocontainers using N rates of 10-20 mM, a larger level than all other treatment combinations. DWU in plastic container-grown plants did not vary among N rates. On the third measurement, DWU was seen to be affected by the main effect of container type with biocontainers providing almost two thirds more mass compared with a plastic container. Plant N concentration and content. N concentration in each structure type (leaf, stem, and root) and average N concentration in the plant were affected by the interaction between N rate and container type, but not by irrigation frequency (Table Two) . N content in leaf, stem, and total plant N content were affected similarly. When grown in plastic containers, plant N content increased with N rate from 0 to 15 mM and peaked at 15 mM N, with no difference between 15 and 20 mM N or between IO and 20 mM N treatments. As a result of greater dry weights, biocontainers resulted in greater N content in leaf, stem, root, and the entire plant than plastic containers at N rates of 15 and 20 mM (Table Two) . Discussion Compared with two irrigations per day, one irrigation per day was seen to result in higher PGI, root N content, greater root dry weight, root length, root surface area, and greater flower number per plant in plastic containers using N rates of 10 and 20 mM (Figure Two; Table Three) . However, irrigation frequency did not affect the dry weight of leaf or stem, SPAD reading, leaf area, or plant N uptake regarding N concentration and content. In the present study, the paper biocontainer produced azalea plant of better quality than those grown in plastic containers, with greater dry weights (leaf, stem, root, or total plant) at high N rates of I0-20 mu. Compared with the larger plant produced using the paper biocontainers, use of plastic containers and one irrigation per day resulted in higher flower number per plant. This finding indicated a competitive relationship between vegetative and reproductive growth of azalea plant. A grower’s choice of container can be made according to their production purpose, whether it is for better-established plant vegetation or more flowers. It was observed that the use of paper biocontainers was liable to result in greater DWU than plastic containers, findings that were consistent with results of previous research in which containers made from recycled paper used more water than black plastic containers. This finding was attributed to the porous nature of the container sidewall. Evapotranspiration, on the other hand, is thought to have a major influence on reducing substrate temperature and help alleviate heat stress during summer. As for the economic aspect of using biocontainers as a sustainable alternative to plastic containers, the main difference in cost of production between a plastic- and a biocontainer production system was attributed to the price of the pot). Increased water use associated with biocontainers was considered to be an insignificant cost in relation to the entire production process. Although biocontainers tend to be more expensive than their plastic counterparts, the advantage of improved plant growth for certain species may help promote adoption of biocontainers. On the other hand, growers have a positive attitude toward adopting sustainable practices such as using biodegradable containers and consumers are thought to be willing to pay a premium for a plant grown in non-plastic containers; both are promising aspects in promoting the use of biodegradable containers. In summary, PGI and dry weight of plastic container-grown plants increased using N rates fromO to 10mMand remained similar at 10-20 mM N. By comparison, when grown in biocontainers, both PGI and dry weight increased from 0 to 15 mM, One irrigation per day resulted in greater root growth and better flower production, although irrigation frequency did not affect plant N uptake. Optimum fertilization for azalea ‘Chiffon’ was ascertained to be 10 mM N when grown in plastic containers and 15 mM N in biocontainers. ■ Table Three. Effect of irrigation frequency on plant growth index (PGI) and root growth of Azalea ‘Chiffon’. Irrigations per day PGI Root Dryness weight (g) Root Length (cms) Root Surface Area (cms) Root Nitrogen Content (mg) One 18.56 4.86 6.36 451.4 24.1 Two 17.35 4.35 5.33 401.9 20.5 Azalea ‘Chiffon’ plants were irrigated either once or twice daily. The overall daily irrigation remained the same.