Comparative analysis of techniques for estimate of the water infiltration in the ground in irrigation for surface

O estudo teve como objetivo proceder a uma anÃlise comparativa de tÃcnicas para estimativa da infiltraÃÃo de Ãgua no solo, com vistas ao dimensionamento, manejo e avaliaÃÃo de sistemas de irrigaÃÃo por sulcos. O estudo foi conduzido no perÃodo de janeiro a fevereiro de 2006 na Ãrea AT1 da Fazenda Experimental Vale do Curu, Pentecoste, Estado do CearÃ, em um Neossolo FlÃvico de textura franco-arenosa. O delineamento experimental adotado foi o de blocos completamente casualizados, constando de cinco tratamentos e quatro repetiÃÃes. Os tratamentos constaram das seguintes tÃcnicas de infiltraÃÃo de Ãgua no solo: cilindro-infiltrÃmetro, sulco-infiltrÃmetro, entradasaÃda, balanÃo de volume I e balanÃo de volume II. A anÃlise dos resultados permitiu as seguintes conclusÃes: - A lÃmina de Ãgua infiltrada no solo apresentou um maior grau de dependÃncia à variÃvel preparo de solo se comparada à variÃvel teor de Ãgua no solo; - As tÃcnicas de balanÃo volumÃtrico apresentaram resultados semelhantes tanto no que diz respeito à lÃmina infiltrada acumulada quanto ao regime assintÃtico; - As tÃcnicas de entrada-saÃda e cilindro-infiltrÃmetro apresentaram valores de infiltraÃÃo acumulada superestimados se comparados aos demais tratamentos analisados; - As tÃcnicas de balanÃo volumÃtrico apresentaram um menor tempo de resposta à obtenÃÃo do regime assintÃtico, caracterÃstica inerente ao processo fÃsico da infiltraÃÃo de Ãgua no solo.The study it had as objective to proceed to a comparative analysis of techniques for estimate of the water infiltration in the soil, with sights to the sizing, handling and evaluation of systems of irrigation for furrow. The study was lead in the period of January the February of 2006 in area AT1 of the Fazenda Experimental Vale do Curu, Pentecoste, Cearà State, in one Neossolo FlÃvico of sand loam texture. The adopted experimental delineation was randomized blocks design, consisting of five treatments and four replications. The treatments had consisted of the following techniques of water infiltration in the ground: cylinder infiltrometer, furrow infiltrometer, nflow-outflow, volume balance I and volume balance II. The analysis of the results allowed the following conclusions: - The water infiltrated in the soil presented a bigger degree of dependence to the variable soil tillage if compared with the variable text of water content. - The techniques of volumetric balance had presented resulted similar in what it says respect to the water infiltrated accumulated how much to the asymptotic regime, allowing to recommends the methodology preconized for Christiansen (1966) in situations where the use of the methodology of Walker and Skogerboe (1987) that if present limitation. - The techniques of inflow-outflow and cylinder infiltrometer had presented values of accumulated infiltration overestimated if compared with the too much analyzed treatments, above all to the methodologies of volumetric balance. - The techniques of volumetric balance had presented a lesser time of reply to the attainment of the asymptotic regime, characteristic inherent to the physical process of the water infiltration in the soil