Pigmentos fotossintéticos, crescimento e produção de Aceroleira sob estresse salino e adubação com combinações nitrogênio - potássio.

Abstract

The use of saline water for crop irrigation in the semi-arid region of the Brazilian Northeast has become a common practice due to water scarcity. Thus, combined nitrogen and potassium fertilization can appear as a technology to mitigate these effects, specifically on the acerola, which presents great socioeconomic viability in this region. In this way, the objective of this research was to evaluate the effects of different levels of irrigation water salinity in interaction with combinations of nitrogen and potassium fertilization on the photosynthetic pigments, growth and production of the cherry tree during the first year of cultivation. The experiment was carried out under field conditions at the Agricultural Science and Technology Center of the Federal University of Campina Grande (CCTA / UFCG), in the city of Pombal, Brazil, using a randomized complete block design with treatments arranged in a factorial scheme (N) and potassium (K2O) fertilization: NK1 = 3, 3, 3, 3, 70% N + 50% K 2 O; NK2 = 100% N + 75% K2O and NK3 = 130% N + 100% K2O, determined based on the recommendation for cultivation of irrigated cherry trees. Three replicates were used and each plot consisted of one plant, totaling 27 experimental units. The cv. White flower, grafted on cv. Reed. The negative effect of irrigation water salinity was evidenced on the growth, chlorophyll a content and average weight of acerola fruits, especially in plants irrigated with CEa of 4.3 dSm-1. The combination of fertilization C1 (70% N + 50% K2O) was more favorable to the growth of plants and production of acerola fruits between 250 and 320 days after transplanting. The combinations of nitrogen and potassium fertilization did not attenuate the negative effects of saline stress on the photosynthetic pigments, growth and fruit production of acerola plants, at 300 days after transplanting.