ABSTRACT
Phosphorus (P) is one of the nutrients that most limits agricultural productivity, especially in tropical soils. Enriched biochar has been proposed to increase the bioavailability of P and other nutrients in the soil. Thus, the objective of this study was to evaluate the availability of P in phosphate biochar (composed of biomass and soil) as a function of the triple superphosphate mixture before and after the pyrolysis process. We produced eight types of enriched biochar via pyrolysis by combining sandy or clayey soil with rice or coffee husk, and by adding triple superphosphate before or after pyrolysis. The heating of the phosphate fertilizer during the pyrolysis process resulted in a higher crystallinity of the phosphates, lower content of labile fractions of P and lower content of available P in phosphate biochars than when the superphosphate was added after pyrolysis. (AU)
Subject(s)
Phosphates/analysis , Oryza , Soil , Pyrolysis , Charcoal/analysis , Coffee , Amazonian EcosystemABSTRACT
The aim of this experiment was to evaluate the biomass yield and chemical composition of the essential oil of clove basil in response to doses of broiler litter (0, 5, 10, 15 and 20 t ha-1) added in presence of triple superphosphate (200 kg ha-1) or without it. Before the first harvest, the height of the plants increased significantly (34.42 cm) when 15 tonnes ha-1 broiler litter were added to the soil. However, after resprouting, the plant heights ranged only as a function of the vegetative cycle, with maximum height (76.0 cm) observed at 60 days. Phosphate fertilization also significantly influenced the leaf area (1.771 cm2 plant-1) during the first harvest. The fresh weight of leaves increased linearly in response to the addition of broiler litter (20 ton ha-1) with maximum yields of 1,709 and 7,140 kg ha-1 during the first harvest and regrowth, respectively. On average, the oil content of the leaves was 0.7%, with maximum performance (3.8 L ha-1) when 20 tonnes ha-1 of broiler litter were added on the soil. Eugenol was found to be the major compound of the essential oil (71.65%).
O objetivo do trabalho foi avaliar a produção de biomassa e a composição do óleo essencial da alfavaca-cravo cultivada com adição ao solo de cama-de-frango de corte, na ausência ou presença de fósforo. Foram estudadas cinco doses de cama-de-frango semi-decomposta (0, 5, 10, 15 e 20 t ha-1), na ausência ou presença de fósforo (200 kg ha-1), na forma de superfosfato triplo. A altura das plantas na primeira colheita foi maior sob a dose de 15 t ha-1 de cama-de-frango (34,42 cm), ou sem o uso de fósforo (32,4 cm); na rebrota, a altura variou apenas em função do ciclo, sendo máxima (76,0 cm) aos 60 dias após a rebrota. A adubação fosfatada influenciou significativamente a área foliar da primeira colheita, que foi maior com fósforo (1.771 cm2 planta-1). As produções de massas frescas de folhas cresceram linearmente com as doses de cama-de-frango, com máximas de 1.709 e 7.140 kg ha-1 na primeira colheita e na rebrota, respectivamente, sob 20 t ha -1. O teor de óleo essencial foi em média de 0,7% e o rendimento máximo de 3,8 L ha-1 sob a dose de 20 t ha-1 de cama-de-frango; o principal constituinte foi o eugenol, com teor médio de 71,65%.