Produção de lima ácida tahiti associada ao balanço energético e hídrico expressa em produtividade da água e eficiência econômica no Pará.

Abstract

Brazil is the fifth largest producer of “Tahiti” acid lime in the world. Among the existing citrus species, this one has the second largest cultivated area in the country, second only to orange. In the state of Pará, citriculture has been growing in recent years, and Tahiti acid lime already occupies 25% of the area cultivated with citrus species in the state. In this region, the first flowering occurs at the end of June and the period of phenological development of the fruits extends until mid-November. A second flowering occurs between October and November. The harvest is concentrated between December and April, when the fruits reach the lowest price in the regional market. This research analysis the energy and radiation balance and the evapotran-spiration of a Tahiti acid lime orchard for three years, as well as the response of irrigated acid lime to four different irrigation depths in a randomized block experiment under the edapho-climatic conditions of the Eastern Amazon. Four irrigation depths, named T1, T2, T3 and T4, were tested. Irrigation was carried out to maintain the soil water potential within the following ranges: below -50 kPa for T1, between -30 and -50 kPa for T2, between -10 and -30 kPa for T3, and above from -10 kPa for T4. The crop response was monitored through the following varia-bles: occurrence of flowers and fruits, productivity, energy balance and gas exchange. An analysis of economic efficiency and water use was carried out, using the gross revenue and the net revenue of the crop, and ratios between fruit productivity or gross revenue and the water applied or consumed by the crop. The results indicate that the surface albedo was 0.13 and the mean evapotranspiration during the two years of the experiment was 3.2 mm day 1, with a crop coefficient (Kc) ranging from 0.74 to 0.84. Irrigation caused an anticipation of the begin-ning of the harvest period and an increase in the total productivity accumulated in the 2020-2021 harvest until February, which increased from 2.22 in T1 to 6.89 kg plant 1 in T4. In the subsequent months, the productivity of the treatments became equal, stabilizing between 6.01 and 8.95 kg plant 1. Water stress induced a second flowering in mid-October in plants that received the lowest irrigation depth, which prolonged the harvest period in this treatment. The different irrigation depths influenced the fresh weight of the harvested fruits, which was higher in the treatment with the highest irrigation depth. Under the conditions of the study, there was no economic viability in any of the treatments tested, due to the low productivity obtained. It was verified that the increase in the irrigation depth reduced the ratio between the gross revenue obtained and the volume of water applied, and there was a reduction in the ratio between the productivity obtained and the water applied.