Resumo

TAPIA VARGAS, Luis Mario et al. Nitrate leaching and nutrient status in two irrigation and nutritional management systems in avocado (Persea americana Mill.). Rev. Int. Contam. Ambient [online]. 2012, vol.28, n.3, pp.251-258. ISSN 0188-4999.

Nitrogen fertilizer is the main nutrient that is used in the avocado orchards of Micho-acán, México. Fertilization applied in July and October agrees with the rainy season so that losses of nitrogen (N) may increase and thereby probably decrease the efficiency of its use, and a likely contribution to environment pollution. Therefore, two systems of water management on nitrate leaching and the effect of foliar nutrition were evaluated. The experiment was conducted in an orchard of avocado (Persea americana Mill) cultivar Hass 10 years old. The measurements period was from January 2002 to December 2006. Treatments were fertilization by micro drip irrigation (RL) and traditional irrigation hose (RT). RL was irrigated from 200 to 50o L of water every 8 days depending on the season, while RT was irrigated every 18 to 21 days by filling 3/4 of the bowl to the way the producer. Fertilization was 220 kg N/h/yr in both treatments. Each treatment was evaluated in four trees, each tree taking every day as a repetition. The N-NO₃ concentration was monitored at three depths 30, 60 and 90 cm and two stem distances 2.0 and 3.0 m, with suction tubes in each tree. Results indicated that RT leached each year from 80 to 96 mg/L N-NO₃ against RL, which produced only 36 to 47 mg/L: the N concentration in leaves was higher in RL with 2.53 % N against 2.20 % in traditional irrigation.

Palavras-chave : avocado nutrition; nutrient leaching; water management.

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