Comparison between Combination of Phosphatic Guano- Steel Slag and Phosphatic Guano-Calcite to Phosphorus Availability on Latosol, Gunung Sindur, Bogor

Abstract

Phosphatic guano is an alternative resource of phosphorus fertilizer, which in this thesis it is introduced as a new cheap fertilizer. As a natural resource, this fertilizer is not famous like the others. That's why; it needs more investigation to recognize the benefits of this fertilizer. Jnst like guano, steel slag also introdnced as a new cheap lime. Steel slag is a by-product formed in the process of steel manufacturing that never been used in agriculture yet. The research was done in laboratory of soil chemistry and fertility, Department of Soil Science, IPB. It was done from December 2000 until July 2001. The objective of this research is, to know more detail the effectiveness combinations of phosphatic guano-steel slag and phosphatic guano-calcite to P availability and others soil properties include pH, exchangeable almninilun (Al), exchangeable calcill1ll (Ca), exchangeable magnesill1ll (Mg), exchangeable kalimn (K), available ferrum (Fe), and available manganese (Mu). The treatments applied to the soil are divided into two parts: (1) phosphatic guano-steel slag treatment and, (2) phosphatic guano-calcite treatment. Phosphatic guano is applied on four levels: GO (0 ppm), Gl (100 ppm P), G2 (200 ppm P), and G3 (300 ppm P). Calcite is applied on four levels: CO (0 x exchangeable Al), CI (1 x exchangeable Al), C2 (2 x exchangeable Al), C3 (3 x exchangeable Al). Slag is also applied on four levels: SO (0 x exchangeable AI), SI (1 x exchangeable AI), S2 (2 x exchangeable AI), and S3 (3 x exchangeable AI). Result of the research showed that the treatment of combination phosphatic guano-steel slag and phosphatic guano-calcite given significant influence to P availability and the others soil properties (except kalium availability). Totally, on one-month incubation and three-month incnbation, the phosphorus availability and the magnesium are higher on phosphatic guano- steel slag treatment than phosphatic guano-calcite treatment, while the exchangeable aluminium is lower and the exchangeable calcium is higher on phosphatic guano-calcite treatment than phophatic guano-steel slag treatment. The femlm availability is lower on phosphatic guano-steel slag treatment than phosphatic guano-calcite treatment, while mangan availability is higher on phosphatic guano-steel slag treatment than phosphatic guano-calcite treatment.