Abstract
This research was conducted to investigate the influence of application rate of liming fertilizers on changes in soil chemical properties and growth of 'Red Madness' petunia in plug production. To achieve this, dolomite (DO) with 0, 1.0, 3.5, 8.0 or 13.0 $g{\cdot}L^{-1}$ and calcium carbonate (CC) with 0, 2.0, 2.5, 3.0, 3.5, or 4.0 $g{\cdot}L^{-1}$ were incorporated into peatmoss + vermiculite (1:1, v/v) during the root substrates formulation. The treatments of 3.5 $g{\cdot}L^{-1}$ of DO and 2.5 or 3.0 $gL^{-1}$ of CC had acceptable ranges of pH and EC in soil solution such as 5.6~6.2 and 0.7~1.0 $dS{\cdot}m^{-1}$, respectively. The faster rising of pH was observed in root media containing CC rather than those of DO. This indicates that the solubility of CC is higher than DO. The soil Ca concentrations in all treatments of CC were 1.8 times as high as those of DO. The treatments of 3.5 or 8.0 $g{\cdot}L^{-1}$ of DO had the highest soil Mg concentrations, but all treatments of CC had lower soil Mg concentrations than control treatment indicating that additional application of Mg fertilizers are required. The elevated application rate of DO or CC resulted in the increase of fresh and dry weight. But plant heights were not influenced by application of liming fertilizers. The results of tissue analysis showed that application of DO or CC influenced the $PO_4{^-}P$, Ca and Mg contents, but not influenced the contents of other nutrients such as N, P, Fe, Mn, Zn and Cu.
