Table 1.
Physico-chemical properties of the saline soil from the field site.
Table 2.
Physico-chemical properties of GWC applied to saline soil.
Fig 1.
A photo of adult Eisenia fetida used in the study.
Table 3.
Levels of factors used for factorial design for the laboratory experiment.
Table 4.
Levels of factors used for central composite design for the field experiment.
Fig 2.
The daily multiplication rate of E. fetida as affected the quantity of GWC and number of E. fetida added in the laboratory experiment.
GWC: green waste compost. Ef-x (x = 10, or 20) indicates the initial number of E. fetida added per microcosm, and GWC-y (y = 0, 60, or 120) indicates the quantity of GWC added per microcosm (g). Values are means ± SE (n = 3). Within each level of Ef, means followed by different letters are significantly different at p≤0.05 according to the SNK test.
Fig 3.
Humic acid carbon content of the soil (g kg-1) as affected by the number of E. fetida and the quantity of GWC added in the laboratory experiment.
GWC: green waste compost. Ef-x (x = 0, 10, or 20) indicates the initial number of E. fetida added per microcosm, and GWC-y (y = 0, 60, or 120) indicates the quantity of GWC added per microcosm (g). Values are means ± SE (n = 3). Within each level of GWC, means followed by different letters are significantly different at p≤0.05 according to the SNK test.
Fig 4.
Available N content in soil (mg kg-1) as affected by the number of E. fetida and the quantity of GWC added in the laboratory experiment.
GWC: green waste compost. Ef-x (x = 0, 10, or 20) indicates the initial number of E. fetida added per microcosm, and GWC-y (y = 0, 60, or 120) indicates the quantity of GWC added per microcosm (g). Values are means ± SE (n = 3). Within each level of GWC, means followed by different letters are significantly different at p≤0.05 according to the SNK test.
Fig 5.
Available P content in soil (mg kg-1) as affected by the number of E. fetida and the quantity of GWC added in the laboratory experiment.
GWC: green waste compost. Ef-x (x = 0, 10, or 20) indicates the initial number of E. fetida added per microcosm, and GWC-y (y = 0, 60, or 120) indicates the quantity of GWC added per microcosm (g). Values are means ± SE (n = 3). Within each level of GWC, means followed by different letters are significantly different at p≤0.05 according to the SNK test.
Table 5.
Decreases in total salt content of the soil relative to the untreated control in the field study; γ = 1.320.
Fig 6.
Response surface for the decrease in total salt content of the soil as affected by the number of E. fetida and quantity of GWC added in the field experiment.
GWC: green waste compost. The fitted model for the response surface was: