Abstract ‘SCS453 Noninha’ and ‘SCS454 Carvoeira’ are new banana cultivars derived from the subgroup Prata (AAB). In comparison with the latter, ‘SCS453 Noninha’ has a low pseudostem height, 'SCS454 Carvoeira' a high yield and both unchanged fruit characteristics. Both also have increased resistance to Panama wilt and ‘SCS454 Carvoeira’ to Sigatoka.

Abstract The rational use of correctives and fertilizers in banana orchards depends on reliable standards for interpreting soil fertility. The study aimed to establish critical levels (CL) for phosphorus (P) and potassium (K) in the soil of banana plantations in Santa Catarina, using the Boundary Line (BL) method. A database with information of soil chemical analysis and fruit yield obtained from orchards in producing regions was used. Scatter plots were obtained relating P and K concentration in the soil extracted by the Mehlich-1 method with the relative productivity of fruits and then the pairs of data in the upper border were selected and used to establish a mathematical model. The model was derived and obtained the concentrations of P and K in the soil that provided the maximum physical productivity (100 %) and maximum economic productivity (90% of the maximum production), corresponding to the CL in the soil. It is proposed that the update of critical levels of P and K for banana cultivation in Santa Catarina to be 85 and 229 mg/dm3, respectively. The banana grower will be able to suppress the P and K doses in a punctual and temporary way in areas of built fertility with the proper monitoring of productivity, soil and leaf analysis.

Resumo O uso racional de corretivos e de fertilizantes em pomares de bananeira depende de padrões confiáveis de interpretação da fertilidade do solo. O trabalho objetivou estabelecer níveis críticos (NC) para fósforo (P) e potássio (K) no solo, em bananais de Santa Catarina, usando o método de Linha de Fronteira (LF). Foi utilizado um banco de dados com informações de análises químicas do solo e da produtividade de frutos, coletados em pomares de regiões produtoras. Gráficos de dispersão foram obtidos relacionando os teores de P e K no solo extraídos pelo método Mehlich-1, com a produtividade relativa de frutos, e, em seguida, os pares de dados da fronteira superior foram selecionados e usados para estabelecer modelos matemáticos. Os modelos foram derivados, e obtidos os teores de P e K no solo, que proporcionaram a máxima produtividade física (100 %) e a máxima produtividade econômica (90 % da produção máxima), correspondente ao NC no solo. É proposto que a atualização dos níveis críticos de P e K no solo, para a bananicultura em Santa Catarina, seja de 85 e 229 mg/dm3, respectivamente. O bananicultor poderá suprimir as doses de P e K de forma pontual e temporária, em áreas de fertilidade construída com o devido monitoramento da produtividade, das análises de solo e de folha.

Resumo A fertilidade do solo e o desequilíbrio nutricional estão entre as principais limitações na produção de banana. O presente estudo teve como objetivo diagnosticar a fertilidade do solo e a nutrição de bananais cultivadas no Estado de Santa Catarina, no Sul do Brasil. Foram realizadas coletas de folhas e de solo, e quantificada a produtividade da banana em 2018 e 2019, em 53 pomares da região do Vale do Itajaí e litoral norte de Santa Catarina. Embora os pomares apresentassem produtividade satisfatória (42 t/ha/ano), eram evidentes as limitações relacionadas à fertilidade do solo e à nutrição da bananeira. O rendimento observado é de 59,6% de seu potencial total. A calagem ainda é recorrente, principalmente antes do estabelecimento do pomar. A aplicação de fertilizantes é generalizada, mas, em muitos casos, as doses são superestimadas. Os teores de Ca, Zn, Cu e B aumentaram nas folhas emitidas em períodos de maior disponibilidade de água no solo e em temperaturas mais altas. Os resultados evidenciam a influência das condições climáticas no fornecimento desses nutrientes às bananeiras. Fatores nutricionais são os principais limitantes da produtividade da banana em Santa Catarina, mais do que fatores não nutricionais.

Abstract Soil fertility and nutritional imbalance are among the main limitations in banana production. The present study aimed to diagnose soil fertility and nutrition of bananas trees cultivated in the state of Santa Catarina, southern Brazil. Leaf and soil samples were collected, and banana yield was quantified in 2018 and 2019 in 53 orchards in the regions of ‘Vale do Itajaí’ and northern coast of Santa Catarina. Although orchards had satisfactory yield (42 t /ha/year), limitations related to soil fertility and banana crop nutrition were evident. The observed yield is 59.6 % of its full potential. Liming is still recurrent, mainly before orchard establishment. Fertilizer application is widespread, but in many cases, doses are overestimated. Ca, Zn, Cu, and B contents increased in leaves emitted in periods of higher soil water availability and higher temperatures. The results highlight the influence of weather conditions on the supply of these nutrients to banana plants. Nutritional factors are the main limiting factors in banana production in the state of Santa Catarina, compared to non-nutritional factors.

ABSTRACT: Urea is a common non-protein supplement used in ruminant feed; however, excessive consumption may lead to poisoning by NH3. Although the slow release of urea into the rumen has shown to be an essential aspect for ruminant feed, to date only a few studies have addressed this matter. In this study we examined the influence of five different NH3-N slow release systems based on clay-urea nanocomposites on the fiber digestibility of low-quality forage (sugarcane straw) in vitro. Physical properties of nanocomposites were evaluated and their effects on digestibility were tested in vitro using pristine urea as a positive control (level of 1 % of DM of sugarcane straw sample) and sugarcane (with no additives) as a negative control. Ammonia release and digestibility were evaluated at 12, 24, 36, 48, 72 and 96-h. Generally, all nanocomposites increased (p < 0.05) digestibility of fiber over control under all the conditions stipulated, but the samples with hydrogel content were more expressive. We concluded that an ideal release rate and optimum environment for microbial synthesis are necessary to maximize the digestion of sugarcane.

ABSTRACT Considerable attention has been given to the development of new nutritional management strategies that can contribute to banana production be overestimated. The present study was motivated by the possibility that fertilizer application in front of the daughter plant might be more effective than application to the total banana production area. This study aimed to determine the most suitable site for soil collection to evaluate the chemical properties when fertilizer is applied in front of the daughter plant; to evaluate the efficacy of organic-mineral fertilizer in terms of soil nutrient availability, and to evaluate the effect on banana production. The experiment was conducted in three consolidated areas of banana plantation in Santa Catarina State. The effects of the combination of two main factors were evaluated: three fertilizer sources (mineral, mineral + organic compost or organic-mineral) and two application management (total area or in front of the plants), together with time (three years) and location (three municipalities). Each treatment was evaluated using a grid containing 20 banana plants (spaced at 2.5 × 2.5 m), with three replications of two plants in the central part. The experiment was arranged in a completely randomized design with three replicates. The use of a mineral source reduced the pH over the years, regardless of the application technique. Application of fertilizers in front of the daughter plant increased available P and K in the soil, compared to the application of fertilizers to the total area “uniformly distributed between banana planting lines and between plants”. In addition, the increase in soil P content was higher using organic-mineral sources. The nutrient contents in the banana leaves did not differ according to the fertilization source. The application of fertilizers in front of the daughter plant optimized banana fertilization and increased fruit production. Under these fertilization conditions, soil for chemical analyses should be collected at around 0.70 m from the site of fertilizer application.

ABSTRACT: Polymer coatings are used to control the rate of release of plant available nutrients from fertilizers as well as to reduce nutrient losses such as ammonia (NH3) volatilization. Although the literature presents several examples of materials used to coat urea, little is known about nitrogen (N) release properties such as the mechanism involved and phenomena (e.g., pore opening) in the polymer coating. Thus, this study investigated urea release from polyurethane (PU) derived from two renewable raw materials (castor oil and soybean oil), to explain how the oil structure and coating microstructure influence release and urea-N dynamics in soil. The results demonstrated that the profile of urea release and the urea-N mineralization in the soil could be controlled by altering the thickness of the coating on the urea granules. Coating by eco-friendly polymer was efficient in controlling urea release in soil to reduce volatilization of ammonia and increase the availability of N in the soil.

ABSTRACT Functionalized charcoal (CHox) incorporated into urea is known for its ability to reduce NH3 volatilization and increase agronomic efficiency. However, it is important to optimize the functionalization process and to elucidate its relationship with the physicochemical properties of CHox for N supply. Thus, charcoal obtained from eucalyptus wood was functionalized with different HNO3 concentrations and reaction times. Ammonia adsorption by CHox was evaluated in chambers with high NH3 concentrations. Dry matter yield, N uptake, and apparent N recovery efficiency of corn plants were evaluated after the application of the urea-CHox mixture to soil in a greenhouse experiment. The properties of CHox, such as pH, isoelectric point, and total acidity (carboxylic and phenolics groups) depended on the HNO3 concentration but were not influenced by the reaction time. The NH3 adsorption by the functionalized charcoal showed a positive correlation with the quantity of carboxylic and phenolic groups and a negative correlation with the pH value and the isoelectric point. The small differences observed in dry matter yield, N accumulation, and apparent N recovery efficiency among the corn plants from urea mixed with CHox or humic acids derived from charcoal (AHCH) are not sufficient to determine the higher efficiency of these sources.

ABSTRACT: High copper (Cu) and zinc (Zn) contents in soil can cause phytotoxicity to plants and contaminate surface and groundwater, with negative effects on agriculture and the environment. Functionalized charcoal (OCh) has high cation exchange capacity (CEC) and the ability to adsorb Cu and Zn and control their availability in the soil and water. An adsorption study at two pH levels was carried out to evaluate increasing Cu and Zn sorption capacity provided by the functionalization process of a charcoal. In addition, a kinetics study of competitive and non-competitive adsorption-desorption of Cu and Zn in OCh was also evaluated. The results showed that functionalized charcoal (Ch) increased CEC 8.7 times due to an increase in carboxyl and phenolic groups, without changing its specific surface area. The Cu and Zn kinetics study showed higher interaction of Cu with the OCh, with total adsorption capacity of 53.1 mg g−1. From this amount, only 74.9 % was desorbed. However, competitive adsorption with Zn reduced the total amount of Cu adsorbed and decreased the Cu affinity for organic matter. This study shows the potential use of functionalized charcoal for control of Cu and Zn availability in the soil solution.

A ureia é o fertilizante nitrogenado mais consumido no mundo, porém a sua eficiência agronômica e econômica é comprometida pela volatilização de NH3, que pode chegar a 78 % do N aplicado. O revestimento da ureia com compostos obtidos pela oxidação ácida do carvão vegetal tem potencial para reduzir a volatilização, em razão do caráter ácido, do elevado poder-tampão de acidez e da elevada CTC. Este trabalho objetivou avaliar o efeito do carvão de eucalipto oxidado com HNO3 no controle da volatilização de NH3 a partir da ureia. Esses compostos foram obtidos a partir da oxidação de carvão de Eucalyptus grandis produzidos nas temperaturas de carbonização de 350 e 450 ºC com HNO3 4,5 mol L-1. Os carvões oxidados (CHox350 e CHox450) foram obtidos por meio da solubilização em meio ácido ou alcalino, semelhante ao procedimento de fracionamento da matéria orgânica do solo. Os CHox foram caracterizados por meio dos teores de C, H, O, N e respectivas relações atômicas, da relação E4 (absorvância 465 nm) / E6 (absorvância 665 nm), da acidez ativa e acidez total (CTC). Avaliou-se o potencial inibidor dos CHox na atividade in vitro da urease de Canavalia ensiformis. Em um sistema fechado com fluxo contínuo de ar, avaliou-se a volatilização de NH3 a partir da ureia perolada sem e com o revestimento de carvão oxidado (U-CHox350 ou U-CHox450). Ambos os CHox mostraram pH próximo de 2,0, mas o CHox350 apresentou maior acidez total, sendo 72 % desta atribuída a grupos funcionais carboxílicos. O CHox350 também apresentou maior variação nas constantes de ionização. Os baixos valores das relações E4/E6 caracterizam a elevada estabilidade dos compostos nos CHox. Os CHox não inibiram a atividade da urease in vitro, no entanto o pico de máxima volatilização a partir da U-CHox350 e U-CHox450 ocorreu 24 h depois daquele verificado para a ureia sem revestimento. A U-CHox350 apresentou menor taxa de volatilização e redução de 43 % na quantidade total de NH3 volatilizada, em relação à ureia sem revestimento.

Urea is the most consumed nitrogen fertilizer in the world. However, its agronomic and economic efficiency is reduced by the volatilization of NH3, which can reach 78 % of the applied nitrogen. The coating of urea granules with acidic compounds obtained by charcoal oxidation has the potential to reduce the volatilization, due to the acidic character, the high buffering capacity and CEC. This work aimed to evaluate the effect of HNO3-oxidized carbon on the control of NH3 volatilization. These compounds were obtained by oxidation of Eucalyptus grandis charcoal, produced at charring temperatures of 350 and 450 ºC, with 4.5 mol L-1 HNO3. The charcoal was oxidized by solubilization in acidic or alkaline medium, similar to the procedure of soil organic matter fractionation (CHox350 and CHox450). CHox was characterized by C, H, O, N contents and their respective atomic relations, by the ratio E4 (absorbance 465 nm) by E6 (absorbance 665 nm), and by active acidity and total acidity (CEC). The inhibitory effect of CHox on the urease activity of Canavalia ensiformis was assessed in vitro. The NH3 volatilization from urea was evaluated with and without coating of oxidized charcoal (U-CHox350 or U-CHox450) in a closed system with continuous air flow. The pH of both CHox was near 2.0, but the total acidity of CHox350 was higher, 72 % of which was attributed to carboxylic groups. The variation in the ionization constants of CHox350 was also greater. The low E4/E6 ratios characterize the high stability of the compounds in CHox. CHox did not inhibit the urease activity in vitro, although the maximum volatilization peak from U-CHox450 and U-CHox350 occurred 24 h after that observed for uncoated urea. The lowest volatilization rate was observed for U-CHox350 as well as a 43 % lower total amount of NH3 volatilized than from uncoated urea.