In Chile, granitic soils are characterized by a low natural fertility, particularly available phosphorus (5 mg/kg) and organic matter (<3%). Bio-based fertilizers (BBFs) derived from residues produced by Chilean aquaculture industry could allow to improve these deficiencies and to support the establishment of pastures in a low-input agriculture system.

In the framework of SEA2LAND project, bio-based fertilizer (BBF) produced by Chilean companies involved in aquaculture waste management were prospected. Three main BBFs were identify:
1) Compost elaborated from fish sludge and silage of salmon in mix with cereals straw (5.5% P2O5);
2) Bone meal derived from the process of salmon protein extraction (19% P2O5); and
3) Dried fish sludge obtained from a high-efficiency drying system (3% P2O5).

In order to evaluate the agronomic value of these BBFs, a field experiment was stablished in Portezuelo city, Chile (36º28’30”S 72º27’40”W). The farm belongs to a smallholder farmer performing lowinput and rainfed agriculture. The environment include a granitic soil with low P content (7 mg/kg of available P2O5) and Mediterranean climate with 800 mm of rain annually. The agronomic value will be evaluated in terms of their phosphorus contribution to the soil-crop system. Each BBFs was incorporated to the soil in a rate equivalent to100 kg/ha of P2O5.

Additionally, two control treatments were considered: 0 and 100 kg/ha of P2O5 supplied as inorganic P (Superphosphate; 46% P2O5). Then, an alfalfa pasture was stablished as a test crop. The effects of BBFs on vigor of early phenological stages of the crop, biomass production, an P recovery in plant tissues will be evaluated. On the other hand, the effects on soil properties (moisture holding capacity, microbiological activity, and P content), will be also measured.

Fig 1: Establishment of experiment for determining the agronomic value of BBFs produced in Chile.
Authors: Luis Inostroza, Juan Hirzel, Francisco Salazar, Ma. Esperanza Sepúlveda / INIA-Chile
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