ALKALINE SEWAGE SLUDGE ADDED BY PHOSPORUS APPLIED ON AN OXISOL FROM ARAPOTI-PR-BRAZIL

Abstract

At the current stage of research with sewage sludges its enrichment with phosphorus (P) can contributes to the reduction of problems related to its final destination and attract farmers to the use of adequate quantities of these biosolids in agriculture. Plus, it can reduce the costs with soil fertilizers and liming operations. This work aimed to evaluate the extractable soil P Mehlich-1 (HCl 0,05 mol dm^-3 + H₂SO₄ 0,0125 mol dm^-3) of an Oxisol, plant P accumulation and its productivity, and the agronomic effectiveness of an alkaline sewage sludge added by phosphorus from the different sources. A sewage sludge from Curitiba, Brazil, was added by 0% P, 0,436% P, 0,872% P e 1,745% P from de partially acidulated phosphate rock Alvorada, single superphosphate and triple superphosphate. Four P addition levels coming from the three sources originated 12 treatments with 4 replications. From the treatments was recommended the dose of 45,85 kg P ha^-1, generating as sole causes of variation sources and levels of phosphorus addition. The treatments was applied to 2,5 kg of an Oxisol from Parana State - Brazil, in vases cultivated with 6 common bean plants. Alkaline sewage sludge added by phosphorus increased the extractable soil P Mehlich-1 and P plant accumulation as well as the grain and dry mass production of common bean. Both the partially acidulated phosphate rock Alvorada as single superphosphate can be used in mixture with alkaline sewage sludge since is considered the level of 0,436% P.