Sugar apple seedling production as a function of substrates and slow-release fertilizer

There is still a lack of studies on the effect of slow-release fertilizers and substrates on the production of high-quality sugar apple seedlings. In this context, the present study aimed to evaluate the quality and biomass of sugar apple seedlings grown in organic substrates at doses of slow-release fertilizer. The experimental design was randomized blocks in split-plot scheme, with four replicates and eleven plants per plot. Substrates were evaluated in the plots (fresh sugarcane bagasse; enriched sugarcane bagasse; coconut powder; commercial organic substrate Tropstrato®), whereas the doses of the slow-release fertilizer Osmocote® were evaluated in the subplots (0; 3; 6; 9; 12 and 15 kg m-3 of substrate). Substrates and slow-release fertilizer doses had effect on the formation of sugar apple seedlings. The effect of slow-release fertilizer is influenced by the substrate used in the formation of sugar apple seedlings. The substrate coconut powder showed the best performance for E%, NL and LAI in sugar apple plants, which reinforces its recommendation to be used in seedling production. For the studied conditions, based on the DQI, we recommend coconut powder associated with the slow-release fertilizer dose of 9 kg m-3 to produce sugar apple seedlings.There is still a lack of studies on the effect of slow-release fertilizers and substrates on the production of high-quality sugar apple seedlings. In this context, the present study aimed to evaluate the quality and biomass of sugar apple seedlings grown in organic substrates at doses of slow-release fertilizer. The experimental design was randomized blocks in split-plot scheme, with four replicates and eleven plants per plot. Substrates were evaluated in the plots (fresh sugarcane bagasse; enriched sugarcane bagasse; coconut powder; commercial organic substrate Tropstrato®), whereas the doses of the slow-release fertilizer Osmocote® were evaluated in the subplots (0; 3; 6; 9; 12 and 15 kg m-3 of substrate). Substrates and slow-release fertilizer doses had effect on the formation of sugar apple seedlings. The effect of slow-release fertilizer is influenced by the substrate used in the formation of sugar apple seedlings. The substrate coconut powder showed the best performance for E%, NL and LAI in sugar apple plants, which reinforces its recommendation to be used in seedling production. For the studied conditions, based on the DQI, we recommend coconut powder associated with the slow-release fertilizer dose of 9 kg m-3 to produce sugar apple seedlings

Modelagem das mudanças nos estoques de carbono orgânico de solos distintos após quatro rotações do eucalipto no sudeste do Brasil com o modelo century

Soil organic matter (SOM) plays an important role in carbon (C) cycle and soil quality. Considering the complexity of factors that control SOM cycling and the long time it usually takes to observe changes in SOM stocks, modeling constitutes a very important tool to understand SOM cycling in forest soils. The following hypotheses were tested: (i) soil organic carbon (SOC) stocks would be higher after several rotations of eucalyptus than in low-productivity pastures; (ii) SOC values simulated by the Century model would describe the data better than the mean of observations. So, the aims of the current study were: (i) to evaluate the SOM dynamics using the Century model to simulate the changes of C stocks for two eucalyptus chronosequences in the Rio Doce Valley, Minas Gerais State, Brazil; and (ii) to compare the C stocks simulated by Century with the C stocks measured in soils of different Orders and regions of the Rio Doce Valley growing eucalyptus. In Belo Oriente (BO), short-rotation eucalyptus plantations had been cultivated for 4.0; 13.0, 22.0, 32.0 and 34.0 years, at a lower elevation and in a warmer climate, while in Virginópolis (VG), these time periods were 8.0, 19.0 and 33.0 years, at a higher elevation and in a milder climate. Soil samples were collected from the 0-20 cm layer to estimate C stocks. Results indicate that the C stocks simulated by the Century model decreased after 37 years of poorly managed pastures in areas previously covered by native forest in the regions of BO and VG. The substitution of poorly managed pastures by eucalyptus in the early 1970´s led to an average increase of C of 0.28 and 0.42 t ha-1 year-1 in BO and VG, respectively. The measured C stocks under eucalyptus in distinct soil Orders and independent regions with variable edapho-climate conditions were not far from the values estimated by the Century model (root mean square error - RMSE = 20.9; model efficiency - EF = 0.29) despite the opposite result obtained with the statistical procedure to test the identity of analytical methods. Only for lower soil C stocks, the model over-estimated the C stock in the 0-20 cm layer. Thus, the Century model is highly promising to detect changes in C stocks in distinct soil orders under eucalyptus, as well as to indicate the impact of harvest residue management on SOM in future rotations.A matéria orgânica do solo (MOS) tem importantes funções no ciclo de C e na qualidade do solo. Considerando a complexidade dos fatores que controlam a ciclagem da MOS e o tempo necessário para que as mudanças sejam nela observadas, a modelagem constitui uma ferramenta muito importante para entender a ciclagem da MOS em solos florestais. As hipóteses do estudo foram: o cultivo do eucalipto por várias rotações resultaria no aumento dos estoques de C do solo, quando comparado a pastagens degradadas; e os valores dos estoques de C do solo simulados pelo modelo Century descreveriam a realidade melhor que a média das observações. Assim, os objetivos do presente estudo foram: avaliar a dinâmica da MOS utilizando o modelo Century para simular as mudanças dos estoques de C para duas cronossequências de plantações de eucalipto no Vale do Rio Doce, Minas Gerais, Brasil; e comparar os estoques de C simulados pelo Century com os estoques de C determinados em diferentes ordens de solo em distintas regiões do Vale do Rio Doce cultivadas com eucalipto. Em Belo Oriente (BO), região de menor altitude e temperatura mais elevada, as plantações de eucalipto têm sido cultivadas por 4, 13, 22, 32 e 34 anos, ao passo que em Virginópolis (VG) - região de maior altitude e temperatura mais baixa - os tempos de cultivos com eucalipto foram de 8, 19 e 33 anos. Assim, foram determinados os estoques de C do solo na camada de 0-20 cm. Os resultados indicaram que os estoques de C simulados pelo modelo Century decresceram após 37 anos de pastagem mal manejada em áreas previamente cobertas por mata nativa nas regiões de BO e VG. A substituição da pastagem mal manejada por eucalipto nos anos 70 resultou, em geral, no aumento de 0,28 e 0,42 t ha-1 ano-1 de C em BO e VG, respectivamente. Os estoques de C determinados sob eucalipto cultivado em distintas ordens de solo e independentes regiões com variáveis condições edafoclimáticas foram ligeiramente próximos aos valores estimados pelo modelo Century (RMSE = 20,9; eficiência do modelo - EF = 0,29), apesar do oposto resultado obtido com o procedimento estatístico para testar a identidade de métodos analíticos. Apenas sob condições de menores estoques de C no solo, o modelo superestimou os estoques de C na camada de 0-20 cm. Assim, o modelo Century tem grande potencial para detectar mudanças nos estoques de C em distintas ordens do solo sob eucalipto em futuras rotações, além de indicar o impacto do manejo do resíduo da colheita na MOS

Micronutrientes foliares na goiabeira fertirrigada com biofertilizante e nitrogênio no semiárido

Required in small amounts, micronutrients play a key role for adequate plant development, which can be supplied by synthetic or organic fertilizers, such as biofertilizers. Thus, an experiment was conducted between July 2014 and August 2015, in the experimental area of the Federal University of the São Francisco Valley, Petrolina-PE, Brazil, to evaluate the micronutrient leaf concentrations of Paluma guava as a function of fertigation with bovine biofertilizer and Nitrogen fertilization. The experimental design was a randomized complete block design (5 x 2) referring to the concentrations of bovine biofertilizer (0, 2.5, 5.0, 7.5 and 10%) and N-fertilizing (50% and 100% of N dose following plant demand), with four replicates and five plants per plot. Only the leaf Mn concentrations are affected by bovine biofertilizer in guava trees fertigated with 100% of recommended N. Leaf concentrations of all the micronutrients (Mn, B, Fe and Zn) are not influenced by nitrogen fertigation. The biofertilizer is efficient in providing Fe.Demandados em pequenas quantidades, os micronutrientes exercem papel fundamental para o desenvolvimento adequado das plantas e podem ser fornecidos por insumos sintéticos ou orgânicos, como os biofertilizantes. Dessa forma, um experimento foi conduzido entre julho de 2014 e agosto de 2015, na área experimental da Universidade Federal do Vale do São Francisco, Petrolina-PE, para avaliar os teores foliares de micronutrientes em goiabeira Paluma em função de fertirrigação com biofertilizante bovino e adubação nitrogenada. O delineamento experimental foi em blocos casualizados em esquema fatorial (5 x 2) referentes às concentrações de biofertilizante bovino (0, 2,5, 5,0, 7,5 e 10%) e adubação mineral com nitrogênio (50% e 100% do recomendado segundo a demanda da cultura), com quatro repetições e cinco plantas por parcela. Apenas os teores foliares de Mn são afetados pelo biofertilizante bovino em goiabeiras fertirrigadas com 100% de N. Os teores foliares de todos os micronutrientes (Mn, B, Fe e Zn) não são influenciados pela fertirrigação nitrogenada. O biofertilizante é eficiente no fornecimento de Fe

Does the irrigated mango cultivation in the semiarid change the Physical and chemical attributes of the soil?

The replacement of native vegetation by crops may result in changes in the chemical and physical attributes of the soil, preventing the sustainability of the agricultural production. Therefore, the aim of this study was to evaluate, in two consecutive years (2014 and 2015), the effect of irrigated mango cultivation in some physical and chemical attributes of the soil in relation to Caatinga in Petrolina-PE, Brazil. In areas under irrigated mango (under the canopy region and the row spacing) and Caatinga (taken as reference), soil samples were collected at the 0-10 and 10-20 cm depths. The chemical and physical analyzes were performed, and were calculated bases sum (BS), cations exchangeable capacity (CEC) and base saturation (V, %). The irrigate mango cultivation (canopy region) increased the macronutrients content (P, K, Ca and Mg), BS and V (%) for both evaluated years at the 0-10 and 10-20 cm depths. In soil under irrigated mango cultivation (under the canopy region and in the row spacing), the macronutrient contents presented a stochastic pattern in the years of 2014 and 2015. The change of land use, from Caatinga to irrigated mango cultivation, does not induce a negative impact in the soil chemical attributes under the adopted management conditions.The replacement of native vegetation by crops may result in changes in the chemical and physical attributes of the soil, preventing the sustainability of the agricultural production. Therefore, the aim of this study was to evaluate, in two consecutive years (2014 and 2015), the effect of irrigated mango cultivation in some physical and chemical attributes of the soil in relation to Caatinga in Petrolina-PE, Brazil. In areas under irrigated mango (under the canopy region and the row spacing) and Caatinga (taken as reference), soil samples were collected at the 0-10 and 10-20 cm depths. The chemical and physical analyzes were performed, and were calculated bases sum (BS), cations exchangeable capacity (CEC) and base saturation (V, %). The irrigate mango cultivation (canopy region) increased the macronutrients content (P, K, Ca and Mg), BS and V (%) for both evaluated years at the 0-10 and 10-20 cm depths. In soil under irrigated mango cultivation (under the canopy region and in the row spacing), the macronutrient contents presented a stochastic pattern in the years of 2014 and 2015. The change of land use, from Caatinga to irrigated mango cultivation, does not induce a negative impact in the soil chemical attributes under the adopted management conditions

Fertilization strategies to reduce the formation of stenospermocarpic mango fruits in the semiarid region

Abstract The mango cultivation has shown considerable losses, due to the intense occurrence of physiological disorders in its fruits, and stenospermocarpy is the main disorder under tropical semiarid conditions. So, the experiment was carried out to evaluate the potential loss of yield of mango cv. Palmer by stenospermocarpy, its relation with the nutritional state of the plant and yield as a function of fertilization strategies. The study was conducted in two experimental areas in the Brazilian semiarid. There is evidence that the leaf contents of phosphorus (P), iron (Fe) and zinc (Zn) influenced the development of stenospermocarpy fruits, associated with high temperature and low relative humidity in the flowering period of the crop. The incidence of fruits affected by stenospermocarpy reaches 90%, with an estimated yield loss of 28.81 Mg ha-1 for the mango cv. Palmer

A new approach to induce mango shoot maturation in Brazilian semi-arid environment

The shoot maturation phase is important for growing mangoes because it precedes the floral induction, when plants are under stress caused by high temperatures and low water availability. Abiotic stress could be alleviated by using plant biostimulant which alters the phytohormone and carbohydrates biosynthesis. Thus, an experiment was conducted to evaluate the use a plant biostimulant containing Ascophyllum nodosum to induce shoot maturation of mango cv. Palmer grown in semi-arid environment. The experimental design consisted of randomized blocks with four treatments, ten replications and five plants per parcel. Treatments consisted of: T1) biostimulant foliar spray + K fertilizer; T2) foliar spray with biostimulant alternating with K fertilizer; T3) individual foliar sprays with magnesium sulfate, potassium sulfate, sulfur and calcium fertilizers, potassium fertilizer and Ethrel®; and T4) Control treatment. The total soluble carbohydrates in leaves, buds and shoots, N, K and S leaf concentrations and fruit production were recorded. The carbohydrate concentrations, nitrogen, sulphur and potassium leaf concentrations and fruit production of mango depend on shoot maturation strategy. Shoot maturation strategy using biostimulant containing Ascophyllum nodosum alternating with K fertilizer from 30 days after PBZ could  be recommended for the production of mango cv. Palmer