تأثير إضافة الحمأة في إنتاجية القطن و القمح و الذرة الصفراء و في تراكم بعض المعادن الثقيلة في التربة و المحاصيل المدروسة

Abstract EN

This study was conducted at Al-Kamary station in the Aleppo province collaboratively between the Arab Center (ACSAD) and the General Commission for scientific Agricultural Research in Syria to study the effect of adding sewage sludge on soil properties and on the productivity of cotton, wheat, and corn.

The accumulation of heavy metals, namely Cd, Cr, Ni, and Pb was monitored in the soil and plant tissue of the studied crops during three subsequent seasons.

Sewage sludge was added to the soil at rates ranging between 6 and 15 ton/ha according to crop N requirement and when its content of heavy metals are less than the thresholds.

Yields from the applied sewage treatments were compared with the treatment received chemical fertilizers, and both of them were compared with the control which did not receive fertilizers or sewage sludge.

The results indicated significant increases in the productivity of some crops grown in the soil that received sewage sludge, and these increases reached 15% in cotton, 36% in wheat grain, 16% in wheat straw and 47% in corn seeds compared with control.

The increase in productivity also reached 2% in cotton, 16% in wheat grain, 10% in wheat straw and 36% in corn compared with chemical fertilizer application.

Increases in the concentrations of heavy metals Pb, Ni, Cr, and Cd were 8.44 , 122, 92, and 0.13 mg/kg, respectively in the soil which received up to 15 ton/ha sewage sludge compared with the control (5.42, 116, 95, 0.07) mg/kg.

However, these concentrations remain within the natural limits (0.1–2) mg/ka of Cd, (1 0-150) mg/kg Cr, (5-500) mg/kg Ni, and (2-200) mg/kg Pb.

No significant increase was found in the concentrations of the heavy metals in plant tissues of the crops cultivated in the soil that received sewage sludge at a rate of 15 ton/ha.

The concentration of the heavy metals in plant tissues remained within the natural range of concentration (0.05-1.20) mg/kg Cd, (1 -5) mg/kg Cr, (0-4) mg/kg Ni, and (0.1-30) mg/kg Pb, and far from toxic and harmful effects on human health according to the international standards.