Cultivo protegido de roseiras sob diferentes lâminas de irrigação no Agreste – PE, Brasil.

Abstract

The response of a rose crop ( rosa sp L.) to increasing irrigation depths grown under protected environment through a plastic cover and a thermoreflective screen made up of aluminized cloth. The experiment was developed in the Flamingo Farm , situated in the county of Garanhuns – Pernambuco, with an average altitude of 896 m, in the coordinates 08º53’25”S of latitude and 36º29’34”W of longitude, and began on 12/06/2006 and ended on 03/08/2007. The experimental design adopted was a completely randomized blocks with three replicates and five treatments. The First Fouu Treatments( 25%; 50%; 75%; 100% of crop evapotranspiration (Etc) managed with an irrigation interval of two days) , with univariate analysis , simple regression and response surface. In the fifth treatment ( managed through tensiometers and 100% of Etc) a residue analysis in relation tothe fourth treatment( 100% Etc) was done. The yield characteristics and crop quality were evaluated for the first four treatments, and the percent residue analysis for the two last ones. Along the time, the irrigation depths studied influenced the stem diameter , the yield per square meter , the bud diameter and the relative growth rate. The bud length, fresh weight and dry weight were influenced at distinct time periods by the irrigation depths applied. The maximum sellingprice of the product was obtained with the application of an irrigation depth corresponding to 77% of Etc. The increasing levels of irrigation depths linearly reduced the number of blind and dead stems. At post-harvest, the variable shelf life showed a decreasing trend with increasing irrigation depths. The treatments influenced in a quadratic manner the accumulated yield given as stems per square meter, of the A80 grade , with maximum levels at about 68% of ETc. The residue analysis indicated that the treatment 100% of ETc was more efficient than the treatment 100% of ETc managed by tensiometers, in the evaluation of the response variables: stem diameter, bud length, bud diameter, fresh and dry mass, yield of stems per square meter, selling value and cummulative yield of the A80 grade. For the variables stem plus bud length and relative growth rate, the treatment 100% ETc managed through tensiometers was indicated as the most efficient. However , for the variables shelf life and blind and dead stems there was none more efficient treatment than the other ones.