EFFECT OF DIFFERENT SOURCES AND RATES OF SOME ORGANIC MANURE ON CONTENT OF SOME HEAVY METALS IN DIFFERENT SOILS AND PLANTS GROWN THEREIN: I. EFFECT ON SPINACH PLANTS

Abstract

This experiment was conducted to study the influence of different sources and rates of some organic manure on growth and heavy metals concentration in spinach plants grown on two different soils. The important results could be summarized in the following: Results show that values of dry weight (DW) of roots, shoots and total plant of corn grown on Abou-Rawash and El-Nobaria soils significantly increased by using all the organic manure sources (sewage sludge(SS), banana and cotton composts (BC and CC) and rates (11, 22, and 44 t/fed)) as compared with control treatment. There is no significant effect between all the used organic manures (SS, BC, and CC) on dry weight production of roots, shoots and total plant of corn grown on Abou-Rawash sandy soil, but in El-Nobaria sandy calcareous soil, the SS and BC treatments significantly increased dry weight of roots, shoots and total plant of corn in comparison with those obtained by using CC treatment. Furthermore, there is no any significant effect between sewage sludge (SS) and (BC) on the production of the dry weight of different organs of corn plant grown on El-Nobaria soil. Dry weight of corn plants grown on both soils significantly increased by increasing the application rate from all the used organic manures up to 44 t/fed. The highest DW of corn plants grown on both soils were obtained by using BC and rate of 44 t/fed, while the lowest values were attained by using CC and rate of 11 t/fed. All the organic manures (SS, BC and CC) led to more significantly increases in the concentration of Zn, Cu, Pb, Cd and Ni in both roots and shoots of corn plants grown on both soils as compared with control. The concentrations of Zn, Cu, Pb, Cd and Ni in corn plants grown on Abou-Rawash significantly increased when BC was applied as compared with CC. Moreover, there is no clear difference could be found between BC and CC used in sandy calcareous soil of El-Nobaria, and the concentration of all the heavy metals in corn plants followed the order of SS > BC > CC in decreasing order. All the concentration of Zn, Cu, Pb, Cd and Ni in corn plants grown on both soils were within the normal range of heavy metals in plants and did not reach phytotoxic studies in the literature. Application of organic manures (SS, BC and CC) resulted in significantly increases of the extractable DTPA and the total metals of Zn, Cu, Pb, Cd and Ni in both used soils after corn plantation as compared with untreated control. Application of SS significantly increased both extractable and total heavy metals (Zn, Cu, Pb, Cd and Ni) in Abou-Rawash and El-Nobaria soils after plantation of corn as compared with CC and BC. Also, the addition of banana compost to Abou-Rawash and El-Nobaria soils significantly increased the extractable as well as the total heavy metals (Zn, Cu, Pb, Cd and Ni) after corn plantation when compared with addition of cotton compost. Generally, the highest values of extractable and total heavy metals in the two tested soils after corn plantation were attained by using sewage sludge (SS) following by BC and CC in decreasing order (SS > BC > CC). The values of extractable and total of content of heavy metals took the following order: Zn > Cu > Pb > Ni > Cd after corn plantation. The extractable heavy metals in Abou-Rawash sandy soil were higher than those obtained in El-Nobaria sandy calcareous soil under all the organic manure treatments and the tested soils. The obtained values of DTPA-heavy metals in the used soils are in the normal range and less than tolerable levels of all studied heavy metals, and could be used as the background level of the heavy metals in uncontaminated soil of Egypt.