Nitrate leaching through climatologic water balance in a fertigated coffee plantation

Revista Ceres

Rafael Pivotto Bortolotto²  Isabeli Pereira Bruno¹  Durval Dourado-neto¹  Luís Carlos Timm¹  Adilson Nunes Da Silva¹  Klaus Reichardt¹ 

[1] ,Universidade Federal de Santa Maria Departmento de Solos Santa Maria Rio Grande do Sul ,Brazil

关键词: Thornthwaite;    Penman-Monteith;    evapotranspiration;    deep drainage;    urea;    Thornthwaite;    Penman-Monteith;    evapotranspiração;    drenagem profunda;    ureia;   

DOI  :  10.1590/S0034-737X2013000600006

来源: SciELO

【 摘 要 】

Nitrate losses from soil profiles by leaching should preferentially be monitored during high rainfall events and during irrigation when fertilizer nitrogen applications are elevated. Using a climatologic water balance, based on the models of Thornthwaite and Penman Monteith for potential evapotranspiration, drainage soil water fluxes below the root zone were estimated in a fertigated coffee crop. Soil solution extraction at the depth of 1 m allowed the calculation of nitrate leaching. The average nitrate concentration in soil solution for plots that received nitrogen by fertigation at a rate of 400 kg ha-1, was 5.42 mg L-1, surpassing the limit of the Brazilian legislation of 10.0 mg L-1, only during one month. For plots receiving 800 kg ha-1 of nitrogen, the average was 25.01 mg L-1, 2.5 times higher than the above-mentioned limit. This information indicates that nitrogen rates higher than 400 kg ha-1 are potentially polluting the ground water. Yearly nitrate amounts of leaching were 24.2 and 153.0 kg ha-1 for the nitrogen rates of 400 and 800 kg ha-1, respectively. The six times higher loss indicates a cost/benefit problem for coffee fertigations above 400 kg ha-1.

【 授权许可】

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