Fenologia do Cupuaçuzeiro (Theobroma grandiflorum [Willd. Ex. Spreng.] Schum.) em um sistema agroflorestal, submetido à diferentes lâminas de irrigação no município de Castanhal, Pa.

Abstract

The cupuaçuzeiro is one of the main native fruit trees in the Amazon region, both economically and socially, generating a source of income and employment for small rural producers, with emphasis on family and indigenous agriculture, making it an interesting alternative for agricultural exploration in the Amazon. , due to its diversity of use, possibilities and uses for agroindustry. It aimed to evaluate the phenology and thermal need of the cupuaçuzeiro in an SAF, in the municipality of Castanhal-PA, under different irrigation depths in order to observe phenological and productivity changes. In the experimental area, a 14 meter high metal tower was installed and an automatic meteorological station was attached to it. Daily ET0 was obtained using the Penman-Monteith method, Phenological activity index, standard deviation in days to determine the lower basal temperature, to determine the upper basal temperature, degree-days proposed by Arnold, with the values of evapotranspiration of reference: T1 = ET0 (0%); T2 = ET0 (50%); T3 = ET0 (100%); and T4 = ET0 (150%) for irrigation, being carried out daily from September to November 2018. Judging by the climatic conditions in the Eastern Amazon, endorsed by the experiment and cited by the literature, the cupuaçuzeiro flourishes from July to December in the driest period of the year, and bears fruit from late July to late April, peaking in March. The cupuaçuzeiro, even being in the understory of the system with covered soil, during the driest period between September, October and November needs at least 1.3 mm.d-¹ of irrigation to avoid loss of ripening fruits. The values of lower basal temperature observed for each phenological phase, in the treatment without water deficit with irrigation of 100% of the reference evapotranspiration, were 10.50 ° C for flowering and 8 ° C for fruiting. And the upper basal temperatures were 34 ° C for flowering and 36 ° C for fruiting. The thermal requirement of the cupuaçuzeiro for the phenological cycle is 2,040.45 ° C day-¹, it is necessary to start the phenological stage of flowering at least 10.50 ° C day-¹, it is 254.13 ° C day-¹ maturation of the fruits. The thermal demand accumulated at the flowering stage is 254.13 ° C day-¹, and 1,786.32 ° C day-¹ at maturation.