International Water & Irrigation

41 exhibited a similar trend as with PGI, which were affected by the interaction of N rate and container type (Table One) . Irrigation frequency affected root dry weight, but not dry weight of leaf, stem, or total plant . The two Azalea ‘Chiffon’ plants were fertilized with 0, 5, 10, 15, or 20 mM nitrogen (N) from ammonium nitrate, grown in plastic containers or paper biocontainers, and irrigated once or twice per day with the same total daily Table One. Plant growth index (PGI), SPAD, dry weights, leaf area, and root growth of Azalea ‘Chiffon’ plants N Rate Container SPAD PGI TDW (g) RDW (g) SDW (g) LDW (g) Leaf Area Root Length (cms) Root Surface Area (cm3) 0 Biocontainer 17 .00 11.10 3.59 1.78 1.36 0.45 43 3601 185 Plastic 12.10 3.80 1.55 1.59 0.66 54 3161 166 5 Biocontainer 24.80 14.90 7.77 3.20 2.22 2.35 199 5697 363 Plastic 16.40 8.83 3.23 2.62 2.98 259 4603 300 10 Biocontainer 32.70 21.90 18.10 6.79 4.90 6.43 553 9805 775 Plastic 19.30 13.66 4.72 4.10 4.84 408 4462 313 15 Biocontainer 35.70 24.30 24.63 8.64 6.58 9.39 849 10668 910 Plastic 17.90 14.56 4.23 4.81 5.53 511 3962 283 20 Biocontainer 38.60 23.90 25.81 8.38 7,54 9.89 944 8774 726 Plastic 17.70 12.06 3.53 4.27 4.26 400 3160 245 Irrigation Effect P value 0.739 0.0107 0.134 0 .0044 0.387 0.230 0.150 0.020 0.047 N Effect P value <0 .001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Container Effect P value 0.794 <0 .001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 N Container P value 0.860 <0 .001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Azalea ‘Chiffon’ plants were fertilized with 0, 5, 10, 15, or 20 mM nitrogen (N) from ammonium nitrate, grown in plastic containers or paper biocontainers, and irrigated once or twice per day with the same total daily irrigation volume. Responses were influenced by the main effect of N rate, irrigation frequency, or the interaction between N rate and container type. TDW stands for total plant dry weight, estimated by summing dry weights of leaf, stem, and root of a given plant; RDW stands for root dry weight; SDW stands for stem dry weight; LDW stands for leaf dry weight. Figure One: Daily water use measured on 30 Aug. (A), and 21 Oct. (B) . Azalea ‘Chiffon’ plants were fertilized with 0, 5, 10, 15, or 20 mM nitrogen from ammonium nitrate and grown in plastic containers or paper biocontainers.