Study of sewage sludge use for the cultivation of plants and its effects on soil properties in Al Ahsa

Abstract EN

negatively affects our environment.

The agricultural application of sludge is an environmentally friendly disposal option.

The current study investigated the use of sewage sludge in the fertilisation of arid land in Al Ahsa, KSA, to reduce the need for importing fertilisers and increase plant productivity.

Sewage sludge was used as an organic fertiliser in the cultivation of cucumber (Cucumis sativa) and lettuce (Lactuca sativa) through its scalable addition to sandy soil at rates of 0 (control soil), 5, 15 and 45% in a pot experiment under greenhouse conditions.

Chemical and microbiological analysis was carried out using a UV spectrophotometer, flame photometer and atomic absorption spectrum.

The results indicated that the application of sewage sludge significantly altered soil properties.

The total dissolved salts (TDS), soluble anions (Cl, HCO3, NO3 and SO4), soluble cations (Na, K, Ca and Mg), nutrients (TKN, TP) and trace metals (Fe, Mn, Cu, Zn and Cr) increased in the sandy soil with the increasing sludge application rates.

For example, the average TDS in the soil increased significantly (p<0.01) from 0.667 gm/l for the control to 1.73, 2.33 and 3.04 gm/l in soil mixed with sludge at 5, 15 and 45 %, respectively.

The application of sewage sludge improved soil properties and increased organic matter from 1.72% in the control soil to 9.36% in the soil mixed with 45% sludge.

In addition, the application of sewage sludge increased the growth yield of lettuce and cucumber plants.

In conclusion, the current study revealed that using sewage sludge as organic manure at a low application rate of 5% can improve the soil's physical and chemical properties, provide plants with the required nutrients, and increase growth and yield.