Resumo

AGOSTINHO, Jorge Manuel Ferreira da Silva. Yield increase in maize production in the Minho region: water use efficiency and cost reduction related to irrigation and fertilization. Rev. de Ciências Agrárias [online]. 2011, vol.34, n.1, pp.24-41. ISSN 0871-018X.

In the Minho region, the irrigation and the fertilization are the most important production factors (44 to 57% of the total cost) in the maize. Soil water balance simulation and the simplified equation of the N balance have increased maize profitability (less 36% of N fertilization) and minimized the leaching flows. The use of drip irrigation increased the average efficiency of water use (66% for traditional irrigation and 43% for the aspersion methods). The drip tape without pumping led to a uniformity of irrigation of 87% and 45% of wet area. Up to 0,75 hectares, the most cost efficient irrigation system is the drip tape without pumping (by gravity). From 0,75 hectares, the aspersion with portable rain-gun is more cost efficient . From 1,8 hectares, the hose-reel machine alone is more cost efficient than the drip tape without pumping. From 3,5 hectares, the adoption of the hose-reel machine and the portable rain-gun is indifferent.

Palavras-chave : Efficiency; fertilization; irrigation; maize; profitability.

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