The lack of information regarding the water requirement of tree species results in water waste in the seedlings production in nurseries. Water requirement, the growth plant factors and water efficiencies for height and diameter were determined for Schizolobium parahyba (Vell.) Blake, Cytharexylum myrianthum Cham. and Ceiba speciosa Ravenna seedlings, under automated irrigation management and greenhouse conditions, located at 22 o 45’53” S and 43 o 41’50” W. We used sewage sludge biosolids as substrate in the seedling phase (280 cm -3 tube), and sandy soil material in the initial pot growth phase (18 dm -3 pot). In the seedlings phase, four water replacement levels were applied to the substrate, by drip irrigation, corresponding to average replacement ranging from 40 (V1) to 100% (V4) of the species water requirement. Seedlings developed properly and 80 days after emergence, S . parahyba , C . myrianthum and C . speciosa seedlings received, respectively, 2.40, 1.08 and 0.85 L per plant, for V4. After growth phase (230 DAE), the total water volumes were, respectively, 70.0, 50.3 and 52.7 L per plant. Under adequate water supply, there were rapid recovery and growth of the species, even for the seedlings which showed different height and diameter in the tube phase. The growth plant factors values found were below 0.5 for all species indicating low sensitivity to growth, both in height and in diameter, in response to water deficit. Water efficiency indicators point to distinct trends between the two phases, and C . speciosa has higher values of water efficiencies for height (80.7 and 17.0 cm L -1 ) and diameter (2.1 and 0.5 mm L -1 ) in both phases.

The lack of information regarding the water requirement of tree species promotes water waste in the seedlings production in nurseries. Water requirement, the growth plant factors and water efficiencies for height and diameter were determined for Schizolobium parahyba (Vell.) Blake, Cytharexylum myrianthum Cham. and Ceiba speciosa Ravenna seedlings, under greenhouse conditions and automated irrigation management. We used sewage sludge biosolids as substrate in the seedling phase (280 cm-3 tube), and sandy soil material in the initial pot growth phase (18 dm-3 pot). In the seedlings phase, four water replacement levels were applied to the substrate, by drip irrigation, meaning average replacement ranging from 40 (V1) to 100% (V4) of species water requirement. Seedlings developed properly and 80 days after emergency, S. parahyba, C. myrianthum and C. speciosa seedlings received, respectively, 2.40, 1.08 and 0.85 L per plant, for V4. After growth phase (230 DAE), the total water volumes were, respectively, 70.0, 50.3 and 52.7 L per plant. Under adequate water supply, there were rapid recovery and growth of the species, even for the seedlings which showed different height and diameter in the tube phase. The growth plant factors values found were below 0.5 for all species indicating low sensibility to growth, both in height and in diameter, in response to water deficit. Water efficiency indicators point to distinct trends between the two phases, and C. speciosa present higher values of water efficiencies for height (80.7 and 17.0 cm L-1) and diameter (2.1 and 0.5 mm L-1) in both phases.

Traditionally, irrigation management has not been used in forest nurseries, compromising the efficiency of the system and the quality of seedlings. In this study, we evaluated the quality of seedlings under different irrigation levels and the substrate composed of pure biosolid, and the initial growth of three Atlantic Forest tree species, produced with automated irrigation management. Four irrigation levels (V1 to V4) were applied by dripping on Schizolobium parahyba (Vell.) Blake, Cytharexyllum myrianthum Chamiáo and Ceiba speciosa Ravenna seedlings. After that, the seedlings were planted to evaluate their early growth in pots. The water was applied in response to species requirement and the volume was measured by water flow sensors, connected to an Arduino MEGA board. Height, collar diameter, leaf area, dry mass and chlorophyll content measurements were used to assess plant development on the seedling and early growth stages. Seedlings that received the highest average volume of water (V4) had a higher rate of growth in height and collar diameter for the three species studied. Despite this, the seedlings that received a smaller volume of water (V1) achieve similar size than V4 ones in pots. The plant growth and quality data, in the two phases analyzed, together with the aggregation of the substrate, indicate that the ideal irrigation level is linked to treatments that received the highest volumes of water (V3 and V4) in the seedling production phase. The results obtained indicate that it is possible to save water and produce seedlings of forest species with quality, ensuring their survival in the field.

Zinnia (Zinnia elegans Jacq.) is a fast-growing and easy to cultivate plant that has flowers of different colors. This species has become an option to be introduced commercially in many countries as cut flower and its floral quality is influenced by different cultivation techniques. We evaluated the production and the quality of floral stems of zinnia (cv. Red California Giant) in response to growing seasons and irrigation levels. In a greenhouse located in Rio de Janeiro (Brazil), zinnia plants were grown in two cycles (autumn-winter and winter-spring) in pots with water replacement corresponding to 46, 64, 75 and 100% of their water requirement. Based on the stem length and diameter and on the flower diameter, there was variation in the quality of the stems produced in the growing seasons evaluated. All stems from the autumn-winter cycle were classified as A1 (high quality), while almost 9% of the stems from the winter-spring cycle were classified as A2 (medium quality). There was a linear growth trend in the production and quality of zinnia stems with the increase of the irrigation level in most cases, as well as significant effect of the growing seasons, with the best results of number of stems, fresh weight, length and diameter of the stem and flower diameter found in the autumn-winter cycle. The weather conditions of this cycle favor the production and quality of zinnia floral stems, and the replacement of 100% of the specie’s water requirement is recommended in both cultivation cycles.

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