Resumen El objetivo de este estudio fue evaluar la pérdida de agua y la composición química de las variedades de pera de cactus forraje sometidas a períodos de almacenamiento poste riores a la cosecha. El diseño experimental adoptado fue un diseño completamente al azar, en un arreglo factorial 3 × 5, que consistía en tres variedades de pera de cactus forrajero y cinco períodos de almacenamiento, con diez repeticiones. Las variedades de pera de cactus forrajero [Doce, Baiana y Orelha de Elefante Mexicana(OEM)] se cosecharon después de 2 años de siembra en condiciones de secano y se almacenaron en un cobertizo ventilado (0, 15, 30, 45 y 60 días). El genotipo Baiana mostró una mayor reducción de agua en los cladodios almacenados en relación con otros genotipos. Todos los genotipos de pera de cactus mostraron una reducción en proteínas crudas y carbohidratos en el período de almacenamiento de 60 días. No hubo pérdidas de nutrientes, materia seca y extracto de éter durante el período de almacenamiento para el genotipo Doce. Hubo un aumento en el contenido de fibra en los cladodios para todos los genotipos almacenados. Durante el período de almacenamiento para cladodios de todos los genotipos, hubo una reducción en el contenido de Ca, Mg y Cu. Las variedades de pera de cactus Doce y OEM se pueden alma cenar hasta 60 días después de la cosecha.

Abstract The objective of this study was to evaluate water loss and chemical composition of cactus pear genotypes submitted to post-harvest storage periods. The experimental design adopted was a the completely randomized, in a 3 × 5 factorial arrangement, with three cactus pear genotypes and five storage periods, and ten replications. The cactus pear genotypes [Doce, Baiana and Orelha de Elefante Mexicana (OEM)] were harvested after 2 years of cultivation under rainfed conditions, and stored in a ventilated shed (0, 15, 30, 45 and 60 days). The genotype Baiana showed greater water reduction in the stored cladodes when compared to the other genotypes. All cactus pear genotypes showed reduction in crude protein and carbohydrates in the storage period of 60 days. There were no losses of nutrients, dry matter and ether extract during the storage periods for the genotype Doce. There was increase in the fiber content of the cladodes of all stored genotypes. During the storage period of the cladodes of all genotypes, there was reduction in the contents of Ca, Mg and Cu. The cactus pear genotypes Doce and OEM can be stored for up to 60 days after harvest.

ABSTRACT Sugarcane is one of the first activities of economic importance in Brazil. The understanding of the nutritional dynamics at different phenological stages of the sugarcane crop with the use of nitrogen-fixing bacteria has been one of the alternatives to decrease fertilizer consumption and increasing plant production. This study aimed to assess the morphophysiological attributes in the initial growth and nutrition of two sugarcane varieties inoculated with strains of diazotrophic bacteria, individually and in an association, in a greenhouse. The experimental design was a randomized block design in a 2 × 8 factorial arrangement with two cultivars (Co 1341-76 and RB 867515) and eight treatments consisting of bacteria inoculated individually with BR 11140T (Azospirillum amazonense), BR 11175T (Herbaspirillum seropedicae), BR 11192T (Herbaspirillum rubrisubalbicans), BR 11281T (Gluconacetobacter diazotrophicus), and BR 11366T (Burkholderia tropica), inoculation associated with the studied bacteria, N fertilization with 120 kg ha-1 of N, and absolute control without inoculation and nitrogen fertilization. Plants were conducted for 75 days after germination, and biometric variables and nutrient accumulation were measured. The sprouting rate index and root fresh matter were significant for inoculation (p<0.01). Inoculation with the strains BR 11192T (H. rubrisubalbicans), BR 11281T (G. diazotrophicus), and RB 11366T (B. tropica) showed the best results for root fresh matter regardless of the cultivar. The strains RB 11366T (B. tropica), BR 11192T (H. rubrisubalbicans), and BR 11175T (H. seropedicae) stood out regarding the sprouting rate index. Inoculation showed a significant effect for stem diameter (p<0.01), especially the strains BR 11140T (A. amazonense) and RB 11366T (B. tropica). All inoculations were efficient for the biometric variable related to leaf length. Nitrogen, Fe, and Zn contents showed a significant effect of the interaction between cultivars and inoculation. The inoculation with the strain RB 11366T (B. tropica), total N fertilization, followed by the other inoculations and the control stood out compared to the cultivar Co 1341-76 within the factor inoculation, indicating that the association of this strain with the cultivar Co 1341-76 is more efficient regarding the recommended commercial N dose for sugarcane. The cultivars Co 1341-76 and RB 867515 responded positively to the individual inoculation of strains of diazotrophic bacteria. The strains promoted improvements in some morphological and/or nutritional attributes of sugarcane plants. The strain B. tropica showed the best interaction with the tested cultivars for the biological N fixation, resulting in gains of biomass productivity and nutrient contents when not inoculated.

Resumo: O objetivo deste trabalho foi avaliar fontes alternativas de potássio para melhoria da fertilidade do solo e da produtividade e da qualidade de bebida do cafeeiro. O experimento foi conduzido em lavoura de café (Coffea arabica) plantada em área de Latossolo, no Município de Patrocínio, no Estado de Minas Gerais. Os tratamentos consistiram da aplicação das fontes de K TK47 e Super Greensand (SG) - ambas baseadas no mineral silicatado glauconita -, nas seguintes doses: 0 kg ha-1 de K2O (controle); 42, 84, 168 e 336 kg ha-1 de K2O de TK47; 618 kg ha-1 de K2O de KCl; e 168 kg ha-1 de K2O de SG. Utilizou-se o delineamento de blocos ao acaso, com quatro repetições por tratamento. As unidades experimentais foram constituídas por três linhas de dez plantas cada uma, tendo-se considerado as oito plantas centrais como parcela útil. A adubação potássica com TK47 aumentou a fertilidade do solo, com correção da acidez e com elevação dos teores de K+, P, Ca2+, da capacidade de troca de cátions efetiva, e dos níveis de Zn2+ e Fe2+ no solo. A adubação com 336 kg ha-1 de K2O de TK47, em dose única, proporciona produção de grãos e atividade de polifenoloxidase semelhantes às da fertilização com 618 kg ha-1 de K2O de KCl, de forma parcelada, mas melhor análise sensorial da bebida resultante.

Abstract: The objective of this work was to evaluate alternative sources of potassium for improving soil fertility and coffee productivity and beverage quality. The experiment was conducted in a coffee (Coffea arabica) crop, planted in an Oxisol area, in the municipality of Patrocínio, in the state of Minas Gerais, Brazil. The treatments consisted of the K sources TK47 and Super Greensand (SG) - both based on glauconite silicate mineral -, at the following doses: 0 kg ha-1 K2O (control); 42, 84, 168, and 336 kg ha-1 K2O from TK47; 618 kg ha-1 K2O from KCl; and 168 kg ha-1 K2O from SG. A randomized complete block design was used, with four replicates in each treatment. The experimental units consisted of three rows with ten plants each, using the eight central plants as the useful plot. Potassium fertilization with TK47 increased soil fertility, correcting soil acidity and elevating K+, P, and Ca2+ contents, effective cation exchange capacity, and Zn2+ and Fe2+ levels in the soil. Fertilization with 336 kg ha-1 K2O from TK47, in a single dose, provides grain yield and polyphenol oxidase activity similar to those of fertilization with 618 kg ha-1 K2O from KCl, in a split-dose, but a better sensory analysis of the resultant beverage.

RESUMO Entre as doenças que causam manchas foliares no algodoeiro, a mancha de ramulária tem se tornado importante em ambientes tropicais, porque as condições climáticas são favoráveis para o desenvolvimento do patógeno. Objetivou-se nesse trabalho avaliar o desempenho dos fungicidas difenoconazol, trifenil hidróxido de estanho, trifloxistrobina, protioconazol e mancozebe, isolados ou em misturas, no controle da mancha de ramulária no algodoeiro. O experimento foi conduzido na safra 2014/2015, em uma fazenda localizada no município de Sapezal, estado do Mato Grosso. O delineamento experimental foi em blocos casualizados e quatro repetições, com parcelas subdivididas no tempo. Foram realizadas sete avaliações de níveis de severidade da mancha da ramulária nos sete tratamentos. Os fungicidas foram aplicados oito vezes, em intervalos de 15 dias. Ao final do período experimental, foi avaliada a produtividade e a eficiência de controle dos fungicidas em comparação com a testemunha. A aplicação de fungicidas reduziu os danos de produtividade devido ao ataque italico fungo Ramularia areola. O trifenil hidróxido de estanho, isolado ou em mistura com o difenoconazol permitiu maior controle da severidade da mancha de ramulária do que a combinação de trifloxistrobina + protioconazol com difenoconazol, ou difenoconazol com mancozebe.

ABSTRACT Among the diseases that cause leaf spots in the cotton crop, ramularia leaf spot has become important in tropical environments since the weather conditions are favorable to the pathogen development. The aim of this study was to evaluate the performance of fungicides difenoconazole, triphenyltin hydroxide, trifloxystrobin, prothioconazole and mancozeb, alone or in mixtures, in controlling ramularia leaf spot in the cotton crop. The experiment was carried out in the 2014/2015 crop season, at a farm located in Sapezal Municipality, Mato Grosso State. Experimental design was in randomized blocks with four replicates and split plot in time. Seven evaluations of ramularia spot severity levels were performed with seven treatments. Fungicides were applied eight times, at 15-day intervals. At the end of the experimental period, the yield and the control effectiveness of fungicides were evaluated in comparison with control. Fungicide applications reduced yield damage caused by the attack of the fungus Ramularia areola. Triphenyltin hydroxide alone or in combination with difenoconazole allowed greater control of ramularia spot severity than the combination of trifloxystrobin + prothioconazole with difenoconazole, or diphenoconazole with mancozeb.

Resumo:O objetivo deste trabalho foi avaliar os efeitos da adubação sobre os teores de P e K, em solo com fertilidade construída, e identificar as doses de N, P e K necessárias para obtenção de maior rentabilidade com a rotação entre soja e milho nesses solos. O experimento foi realizado durante três safras, em propriedade com alto investimento tecnológico, em Latossolo Vermelho-Amarelo argiloso de Cerrado, com elevada fertilidade. Utilizou-se o delineamento de blocos ao acaso, com parcelas subdividas e três repetições. Os tratamentos consistiram de 0, 50, 100 e 150% das doses de fertilizantes NPK recomendadas na semeadura (parcelas) e das doses de KCl (soja) e N (milho) em cobertura (subparcelas). Mesmo após a colheita das três safras, os teores de P (Mehlich-1) se mantiveram inalterados no solo sem adubação. Além disso, não houve decréscimo na produtividade da soja na ausência de adubação. O milho, no entanto, foi mais sensível à redução de adubação, com o máximo retorno econômico obtido com 312 kg ha-1 do adubo formulado 10-32-10, e 263 kg ha-1 de ureia em cobertura. Solos com fertilidade construída demandam ajustes de manejo de adubação, para o uso eficiente dos fertilizantes em lavouras com alto investimento tecnológico.

Abstract:The objective of this work was to evaluate the effects of fertilization on P and K levels in soil with improved fertility, and to identify N, P, and K doses needed to provide the greatest profitability in a rotation between soybean and corn in these soils. The experiment was carried out for three harvest seasons, in a farm with high technological investment, in a clayey Oxisol from Cerrado with high fertility. A randomized complete block design was used, in a split-plot arrangement with three replicates. Treatments consisted of 0, 50, 100, and 150% of the recommended rates of NPK on sowing (plots), and of KCl (soybean) and N (corn) at topdressing. Even after three harvests, P (Mehlich-1) contents remained unchanged in the soil without fertilization. Moreover, soybean yield did not decrease in the absence of fertilization. However, corn was more sensible to the reduction of fertilization, with the maximum economic return obtained with 312 kg ha-1 of the 10-32-10 fertilizer formulation, and of 263 kg ha-1 urea at topdressing. Soils with improved fertility demand adjustments of fertilization management for the efficient use of fertilizers in crops with high technological investment.

As substâncias húmicas (SH) representam o principal reservatório de carbono orgânico total do solo (COT) e sua partição entre diferentes frações de solubilidade em meio alcalino ou ácido pode guardar relação com o tipo de solo e manejo adotado. O objetivo deste trabalho foi comparar a partição das SHs, de acordo com profundidade, tipo de solo, bioma e uso do solo no Brasil. Revisou-se a literatura, incluindo teses, dissertações, artigos e resumos em anais de eventos, em busca de dados sobre o teor de COT, sua porcentagem como ácidos húmicos (AH), ácidos fúlvicos (AF) e humina (HU) e a razão AH/AF. Os dados foram estratificados por intervalos comparáveis de profundidades (0-5, 5-10, 0-20, 20-50, 50-100 e >100 cm), biomas (Mata Atlântica, Cerrado, Amazônia, Pampa e Caatinga), ordem de solo (Argissolo, Latossolo, Cambissolo, Planossolo, Neossolo, Gleissolo e Organossolo) e principais usos do solo (florestas nativas, pastagem natural, pastagem plantada, eucalipto, culturas perenes e anuais). Os dados foram analisados por estatística descritiva, correlações de Spearman e análise de componentes principais (ACP). Nos Argissolos, Latossolos e Organossolos, a fração HU contribuiu com metade do COT, tendendo a diminuir em profundidade. Para Latossolos e Organossolos, a fração AF tendeu a aumentar em profundidade. Em Neossolos, a fração AH aumentou em profundidade, embora tenha diminuído em Gleissolos e Planossolos. A razão AH/AF geralmente diminui em profundidade. Pela ACP, não foi possível identificar um padrão de agrupamento das amostras em razão do tipo de bioma e uso do solo, sugerindo que a partição das SHs tem baixo potencial como indicador de efeitos do manejo ou condições ambientais, embora seja útil para discriminar processos de humificação em algumas ordens de solo.

Humic substances (HS) are the main pool of total soil organic carbon (TOC). They are partitioned in different fractions according to its solubility in alkali or acid medium, which can be related to soil type and management. This work aimed to compare HS partitioning in Brazilian soils according to soil depth, soil type, biome, and land uses. In a literature review of theses, dissertations, journal articles, and abstracts in proceedings, quantitative data on TOC partitioning in humic acids (HA), fulvic acids (FA), and humin (HU), as well as the HA/FA ratio were compiled. The data were sorted according to comparable depths (0-5, 5-10, 0-20, 20-50, 50-100, and >100 cm), biomes (Atlantic rainforest, Cerrado savanna, Amazon rainforest, southern prairies, and Caatinga scrubland), soil order (Ultisols, Oxisols, Inceptisols, Entisols, Histosols and soils with aquic moisture regimes), and land use systems (native forests, prairies, pastures, eucalypt, and annual or perennial crops). Data were analyzed by descriptive statistics, Spearman correlation, and principal component analysis (PCA). In Ultisols, Oxisols, and Histosols, humin accounted for at least half of TOC and tended to decrease with depth. In Oxisols and Histosols, FA tended to increase in depth. In the Entisols, HA increased with depth, but decreased in Histosols and some Ultisols. Generally, the HA/FA decreased in the deeper layers. Results of PCA indicated no effect of biomes and land use systems on the quantitative partitioning of HS, suggesting its low potential as indicator of management effects or environmental conditions, although useful to discriminate humification processes in some soil taxa.

In this study honey samples produced in the southwest of Bahia were characterized based on physicochemical and mineral (Ca, Mg, Na, K, Mn, Fe and Zn) composition. The metals were determined by atomic absorption spectrophotometry. The application of multivariate analysis showed that the honey colors are consequence of the mineral and physicochemical compositions. The darkest honey samples are characterized by higher values of pH and for presenting a strong relationship with Ca and Fe content.

Neste trabalho, amostras de mel produzidas em três diferentes regiões climáticas do Sudoeste da Bahia, Brasil (semi-árido, Mata Atlântica e Zona de Transição Climática) foram caracterizadas com base nos teores de minerais, elementos traços, cinzas e condutividade elétrica. Os metais foram determinados por espectrometria de absorção atômica. Com a finalidade de avaliar as variáveis químicas capazes de promover uma caracterização do mel produzido em cada região, as técnicas de cluster e componentes principais (ACP) foram aplicadas nos resultados das análises. Com base nas análises de cluster e ACP, foi possível distinguir os diferentes grupos de amostras correspondentes às três origens geográficas dos méis. A elevada correlação observada entre a condutividade elétrica e Cu nas amostras das zonas de transição climática, sugere que essas variáveis estão associadas, e esse fato pode ser atribuído ao uso de cobre na cafeicultura que é a principal atividade agrícola desenvolvida nessa região.

In this study, samples of honey produced in three different regional climates in the southwest Bahia, Brazil (semi-arid, Atlantic and Transitional Forest Zones) were characterized on the basis of their mineral and trace elements, ash content and electrical conductivity. The metals were determined by atomic absorption spectrophotometry. The cluster and principal component analysis (PCA) methods were applied to the chemical concentration data in order to study the chemistry variables capable of promoting a characterization of the honey produced in each area. Cluster analysis and PCA distinguishes the different groups of honey samples corresponding to each region of the three geographical origins. The high correlation between electrical conductivity and Cu observed in honey samples from transitional forest zones suggested a coupling to the nutrient cycle, and can be attributed to use of copper compounds in coffee production, a major activity developed in all transitional forest zones.