RESUMO Objetivou-se com o presente trabalho avaliar durante três ciclos de produção, os teores de nutrientes e a eficiência nutricional em Palma forrageira ‘Gigante’ submetida a diferentes adubações química, orgânica e organomineral, configurações de plantio e espaçamentos. Setenta e dois tratamentos, envolvendo dois tipos de arranjos nas parcelas, três espaçamentos nas subparcelas e 12 tipos de adubação nas sub-subparcelas foram dispostos em esquema de parcelas sub-subdivididas, em delineamento experimental em blocos casualizados, com três repetições. Na época da colheita de cada ciclo produtivo, coletaram-se 40 amostras de tecidos dos cladódios por tratamento para determinação da massa de matéria seca e dos teores de nutrientes e a partir destes calcularam-se os coeficientes de utilização biológica dos nutrientes. Verificou-se que a adubação orgânica diminui os teores de Mn nos cladódios abaixo da faixa de suficiência. A eficiência nutricional de N, P, S, Mn e Zn é maior com adubação orgânica e organomineral e estão associadas às maiores produtividades de matéria seca, enquanto de K é maior com adubação mineral. A ausência de adubação ou aplicação de 30 Mg ha-1 ano-1 de esterco bovino é insuficiente para assegurar o estado nutricional e produtividade de matéria seca acima de 15 Mg ha-1 em palma forrageira ‘Gigante’.

ABSTRACT The objective of this study was to evaluate nutrient concentration and nutritional efficiency in ‘Gigante’ cactus pear under different chemical, organic and organomineral fertilizations, planting configurations and spacings, during three production cycles. Seventy two treatments, involving two types of configuration in the plots, three spacings in the subplots and 12 types of fertilization in the sub-subplots were arranged in a split-split-plot scheme, in a randomized block design, with three repetitions. At the time of harvest of each production cycle, 40 cladode tissue samples were collected per treatment to determine dry matter mass and nutrient concentration, which were used to calculate the coefficients of biological utilization of nutrients. Organic fertilization reduces Mn concentrations in cladodes to levels below the sufficiency range. The nutritional efficiency of N, S, P, Mn and Zn is higher with organic and organomineral fertilizations and are associated with higher dry matter yields, whereas K nutritional efficiency is higher with mineral fertilization. The absence of fertilization or application of 30 Mg ha-1 year-1 of bovine manure is insufficient to ensure nutritional status and dry matter yield above 15 Mg ha-1 in ‘Gigante’ cactus pear.

ABSTRACT The objective of this study was to evaluate the nutrient contents in ‘Tommy Atkins’ mango leaves at the flowering and fruiting stages under different strategies to reduce irrigation levels during flower induction. Five irrigation level reduction strategies, based on crop evapotranspiration (ETc) were used in the plots: T1 (0% ETc), T2 (25% ETc), T3 (50% ETc), T4 (75% ETc) and T5 (100% ETc); two production cycles in the split-plots; and in two development stages, flowering and harvest, in the split-split plots. The content of N, P, K, Ca, Mg, and S, as well as B, Cu, Fe, Mn, Zn, and Na was determined and leaf chlorophyll index was measured during the second cycle. The content of P, K, Mg, and Cu in the ‘Tommy Atkins’ mango trees leaves varied according to phases and cycles, regardless of the strategies to reduce irrigation levels in floral induction. The contents of N, Ca, B, Fe, Mn, and Na varied with stages and with the production cycles, in an independent manner. Foliar N contents were above the sufficiency range at the different development stages and cycles evaluated. The indices of a, b, and total chlorophyll varied independent of reading time. The nutrient contents with lower mobility in the plant, Ca, B, Fe and Mn increase in ‘Tommy Atkins’ mango trees leaves from flowering to fruiting, with the return of irrigation at 100% crop evapotranspiration, while the levels of N, P, K and Mg, nutrients with high mobility in plant decrease.