Diagnóstico dos níveis de degradação dos solos por sais e da produtividade do coqueiro no perímetro irrigado Curu Pentecoste, Ceará

Abstract

The survey was conducted in the Irrigated Perimeter Curu Pentecost and aimed to assess the extent of degraded soils by salts and the coconut productivity in the eight hydraulic perimeter sectors. Farmers are family based on number of 173, each occupying an area of about 4.13 ha, which are irrigated by surface through the furrow system. Soil samples were collected in all sectors, following a pattern collection in the 0 - 0.3 m, at random, in total of seven collections to form a sample of each agricultural plot. In these samples the electrical conductivity in the 1:1 soil:water extract (EC1:1) and the proportion of extracted sodium (soluble + exchangeable) were determined. EC1:1 data were corrected for saturation extract. It was used as a reference for the stratification of degraded soils by salts, classification proposed by Pizarro (1976), which is an adaptation of the American classification of the US Salinity Laboratory. We conducted a diagnosis of coconut yield, to represent 74% of the cultivated area where soil samples were taken. The results allowed the following conclusions: - In two thirds of the total sampled area were identified soils with EC greater than 2.0 dS m-1 and / or PST higher than 7%; - Maps of iso salinity and iso sodicity allowed us to visualize a predominance of degraded soils by salts on the right bank of the Curu river; - Coconut yield are within the reference range at all hydraulic sectors evaluated; The difference in coconut yield keep a more direct relationship with crop management than with the proper levels of soil degradation by salinity.