Levantamento do mapa de solos da bacia de irrigação do açude público Santo Antônio de Ruças : Município de Ruças, Estado do Ceará

Abstract

Engineer Edilberto Amaral, the author, pays homage to the organizers of the soils service of the Federal Department of Works Against Drought (Inspectoria Federal de Obras Contra a Seca), and continues by explaining the method used in this work, which is different from that used by the Agronomic Institute of Campinas. He explains that the difference is due to the diversity of aims In the Federal Department's Work, the soils were separated by their superficial characteristics, including vegetation; the outlines were studied in their morphology, physical-chemical characteristics, at first in a small field laboratory and later, with greater care, in the laboratory of the José Augusto Trinidade Institute at S. Gonçalo, Paraíba.

            He describes the methods of collecting the samples and establishes the different types of soil in the area studied, which are in quality and quantity as follows:

            Table-land 16,9%; plain of table-land 24,1%; plain 4,8%; salty flood land 14,3%; flood land 30,9%; and river bed 9%, which in all covers an area of 456 hectares.

            He then describes the essential characteristics of each type of soil, calling attention to the excellence of the flood land, the versatility of the table land, and the adaption of the "carnaubeira" to the salty flood land.

            After analytical facts referring to the Ruças dam for the purpose of comparison, the author brings up those facts which refer to the irrigation basin of the São Gonçalo dam. He considers the water destined for irrigation and concludes that the water is of mediocre quality and in insufficient quantity for irrigating the entire Ruças basin.

            He finishes the article with the following conclusions:

1) The area that can be irrigated with the available water, is scarcely 130 hectares;

2) The problem of the passage of the canals to the left bank of the São Pedro river; no longer exists;

3) Along with the construction of the canals, the drainage net-work should be installed in the salty flood land;

4) The fertility of the soils of the Northwest is a myth, owing to the problems of irrigation and fertilization.