3.3. Impact of physico-chemical parameters of soil substitutes on the Sinapis alba germination
The relationships between parameters reported in Tables 5 and Figure 3 have shown various interactions. The increase of Ca concentration (5.32-8.23%) in the soil substitutes has induced a decrease in S content (2.66-4.12%), but simultaneously raised pH and EC. Therefore, it should be hypothesized that only S induced pH decrease and was not directly and solely responsible for the control of the salinity of soil substitutes. Chemically, calcium reacts with sulphate ion (SO42-) to form some compounds reducing the chemical reactivity of SO42. The physical and chemical parameters of soil substitutes prepared at the stage III were presented in Table 5.
TABLE 5 Physical and chemical characteristics of soil substitutes at the stage III