AVALIAÇÃO COMPARATIVA DO ESTADO NUTRICIONAL DE MUDAS DE BARU (<i>Dipteryx alata</i>)

Abstract

RESUMOPara o sucesso de um processo de revegetação, além de melhorar as condições edáficas da área, deve-se dispor de mudas de boa qualidade, o que pode ser avaliado pelo estado nutricional. Neste trabalho, avaliaramse os teores foliares de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn de mudas de Dipteryx alata produzidas a pleno sol ou em cultivo protegido (30% de sombreamento), utilizando como substrato solo degradado, condicionado ou não com resíduo orgânico (32 t ha -1 macrófitas) e com diferentes doses de fósforo (0, 100, 200 e 300 mg dm -3 P2O5), comparativamente à mudas e parte aérea de plantas adultas, coletadas em campo A cada coleta de folhas em campo, o solo foi coletado e analisado para P, MO, pH, K, Ca, Mg, H+Al, SB e CTC. A mesma análise foi realizada nas unidades experimentais, ao final do experimento. Os resultados mostram que o Dipteryx alata é pouco exigente em P, que os teores foliares, nas mudas de campo, são superiores às plantas adultas em N, P, K e S e inferiores para Ca e que o estádio de desenvolvimento da planta não influenciou os teores foliares de Mg, B, Cu, Fe, Mn e Zn. O resíduo orgânico não foi suficiente para fornecer o N necessário às mudas produzidas. O cultivo a pleno sol propiciou maiores teores foliares de N, P, Ca, Mg, B, Cu, Fe e Mn. Teores foliares de N, P, K, Ca, B, Fe e Zn foram superiores na presença de resíduo orgânico. Palavras-chave: solo degradado; resíduo orgânico; cerrado. ABSTRACTTo a successful revegetation process, besides improving the edaphic area conditions, seedlings must have good quality, which can be assessed by nutritional status. This research evaluated the foliar contents of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn from Dipteryx alata seedlings produced under full sun or protected condition (30% of shade), using degraded soil as substrate, with or without organic residue added (32 t ha -1 macrophyte) and with different phosphorus doses (0, 100, 200 e 300 mg dm -3 P 2 O 5 ), comparatively to seedlings and adult plants collected in the field. To each leaf sampling in the field, the soil was collected and analyzed for P, MO, pH, K, Ca, Mg, H+Al, SB and CTC. The same analysis was performed in the experimental units at the end of the experiment. The data showed that the Dipteryx alata presents low P requirement. The foliar levels, in seedling from field were higher than in adult plants, for N, P, K, and S, and lower for Ca, and the plant's developing stadium did not affect the foliar levels of Mg,

Determination of Optimal Nutrient Levels in Baru Seedlings (Dipterix alata Vog.) Using the Mathematical Chance Method

“…The sufficiency ranges established for magnesium (Mg) were 0.74 to 1.50 g per kg, covering classes 1 and 2, and similarly, for sulfur (S), the classes determined by ChM were 1 and 2, with values of 1.26 to 2.26 g per kg. These values are similar to the leaf content levels found for baru by Boni et al (2016), Silva et al (2019), andSouza et al (2018), confirming the optimal leaf nutrient levels for the crop.…”

“…When comparing these results with those of Souza et al (2018), the obtained Ca values were much lower, ranging from 22.39 to 24.77 g per kg in their study. Boni et al (2016) and Silva et al (2019) reported nutritional levels consistent with the sufficiency range values obtained by ChM.…”

“…Potassium (K) was grouped based on ChM values greater than 2.77 g per plant, encompassing classes 4 and 5, with sufficiency limits ranging from 17.90 to 24.00 g of K per kg (Table 2). The sufficiency range values were higher than the content of 10.8 g per kg obtained by Boni et al (2016) and lower than the 28.04 g per kg reported by Souza et al (2018). The range determined for K by ChM differed from the values reported in previous studies on baru nutrition, highlighting the need to establish a reference for seedling production of this species.…”

“…Therefore, for N, the ChM values were determined between classes 2 and 4 (19.06 to 28.14 g per kg), as proposed by Camacho et al (2012a). Boni et al (2016) reported N content values in baru seedlings of 26.4 g per kg, which falls within this range. While evaluating Baru's nutritional status, Souza et al (2018) found that suitable N levels for seedling development ranged from 20.20 to 26.00 g per kg.…”

Phosphate and nitrogen fertilization in the production of Barueiro (Dipteryx alata Vog.) seedlings

“…Silva (2018) verified larger stem diameter of barueiro seedlings produced with the application of 200 mg dm -3 N associated with 30 mg dm -3 S. The same author recommended the use of 300 mg dm -3 P 2 O 5 , which provided stem diameter of 6.75 mm. Boni et al (2016) evaluated leaf nutrient contents in barueiro seedling grown under full sun or in protected cultivation on substrate conditioned or not with organic residue and with different phosphorus concentrations (0, 100, 200 and 300 mg dm -3 P 2 O 5 ) and found that seedlings were undemanding in phosphorus. Considering the leaf P contents observed in seedlings produced, the authors stressed the importance of phosphate fertilization so that adequate amounts are available to plants.…”