ARAÚJO, B. L. B.; http://lattes.cnpq.br/9072702215731433; ARAÚJO, Bruno Ligier Barreiro de.
Abstract:
The Caatinga, a unique and exclusively Brazilian biome, has suffered constant
degradation in recent years due to disordered and predatory use. Thus, several
strategies have been sought to conserve forest resources and to produce native
seedlings with desirable characteristics and tolerance to adverse conditions. The
quality of the seedlings depends on several factors, such as irrigation management
and substrate type. In this context, this study aimed to determine the effect of water
stress on the development of Sabiá (Mimosa caesalpiniifolia Benth) and Mulungu
(Erythrina velutina Willd) seedlings, in the forest nursery of the Rural Health and
Technology Center/CSTR, Patos/PB campus. The design was completely
randomized (CRD), in factorial scheme 3 x 2, with 3 levels of water stress (WS), WS1
(100% of water requirement, WR) without stress, WS2 (70% WR), WS3 (40% WR)
and two forest species (Sabiá and Mulungu), with 5 repetitions. Germination, growth,
phytomass production, seedling quality, water consumption and water use efficiency
were evaluated up to 150 days after sowing (DAS). The results indicate that irrigation
with 100%, 70% and 40% of WR did not influence the germination phase of forest
species, with a germination percentage of 45% for Mulungu and about 25% for
Sabiá. In irrigation with 100% of WR the Mulungu presented higher average values of
growth, fresh and dry weight (shoot and root) and Dickson Quality Index (DQI). At the
end of the experiment, it was found in the treatment without water stress the DQI of
0.55 for Sabiá and 9.48 for Mulungu. It was observed that the water deficit increase
affected the growth variables of Mulungu seedlings, while the species Sabiá had no
significant influence. At 150 DAS, the Mulungu obtained water use efficiency (WUE)
higher than the Sabiá with the application of 70% and 100% of the WR of this
species, with water consumption (WC) of 3.25 L and 4.65 L, respectively. In this
context, when evaluating all variables, it is suggested the application of 40% of the
WR depth for Sabiá and Mulungu in the germination phase, providing a 60%
reduction in the use of irrigation water of these species. It is recommended to use the
irrigation of 40% of the WR for the Sabiá and 100% of the WR for the Mulungu during
the growth phase of the seedlings, aiming to obtain seedlings with greater vigor in a
shorter period, resulting in greater efficiency of water use.