Sewage sludge and farmyard manure ratios in growing media affect nutrient and heavy metal contents in cucumber

This study aimed to determine the effects of substituting sewage sludge for farmyard manure in seedling growing, media on the total dry weight, as well as nutrient and heavy metal contents of cucumber plants. Seedling growing, media consisted of 2:1:2 soil (S), pumice (P) and an organic fertilizer mixture [farmyard manure (FM) + sewage sludge (SS)]. Then, SS was progressively substituted for FM, at rates of 0%, 25 %, 50%, 75 %, and 100%. Treatments were placed in a growth chamber. No additional nutrients were applied. Dry weight, and Fe, Mn, B, Zn, Cu, Mo and Cd contents were found to increase with increases in SS ratios. Conversely, N, P, K, Ca, Mg and S contents increased with increases in FM ratios. Applications of 0:1 and 1:3 FM:SS ratios provided the best results based on dry weight of seedlings; however, when plant nutrient an heavy metal contents were taken into consideration, 1:1 and 3:1 FM:SS ratios were found to be preferable.