Table 1.
Treatment no. | Orthogonal array | N concentation |
P concentration, Na2HPO4 | K concentration, K2SO4 | Other nutrients | |
---|---|---|---|---|---|---|
(NH4)2SO4 | NaNO3 | |||||
1 | N P K | 2 mm | 4 mm | 1·33 mm | 2 mm | 1·5 mm MgSO4·7H2O, 4 mm CaCl·2H2O, 0·1 mm FeEDTA, 2·86 mg L−1 H3BO3, 1·81 mg L−1 MnCl2·4H2O, 0·5 mg L−1 ZnSO4·7H2O, 0·08 mg L−1 CuSO4·5H2O, 0·025 mg L−1 NaMoO4·2H2O |
2 | N –P –K | 2 mm | 4 mm | 0 | 0 | |
3 | N 2P 2K | 2 mm | 4 mm | 2·66 mm | 4 mm | |
4 | –N P –K | 0 | 0 | 1·33 mm | 0 | |
5 | –N –P 2K | 0 | 0 | 0 | 4 mm | |
6 | –N 2P K | 0 | 0 | 2·66 mm | 2 mm | |
7 | 2N P 2K | 4 mm | 8 mm | 1·33 mm | 4 mm | |
8 | 2N –P K | 4 mm | 8 mm | 0 | 2 mm | |
9 | 2N 2P –K | 4 mm | 8 mm | 2·66 mm | 0 |
In the orthogonal array, ‘–’ indicates absence of the nutrient in the nutrient solution; ‘2’ indicates doubled concentration of the nutrient in the solution. (NH4)2SO4 and NaNO3 were used in combination instead of either one alone in order to facilitate nutrient uptake, because preference of N forms remains unknown. All solutions were adjusted to a pH value of 6·5 (with 0·1 m NaOH or 0·1 m HCl) before use.