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The bulk density values indicative of compaction in clayey soils correspond to a wide range of values (1.30-1.47 Mg m-3), due to the diverse types of soil management. Our hypothesis is that if we consider bulk density values within similar management groups (those that fall to the ground and those that do not fall), the values will be more accurate within each management group. Our objective in this work was to analyze using the concepts of (Yates & Cochran, 1938; Whitehead, 2002) what is a suitable statistical way of grouping these results to reach a consensus regarding a tested hypothesis, the greatest number of density values surveyed between 1977 and 2021, considered for the study of compaction in clayey Oxisols under different managements, to verify whether our hypothesis will be confirmed. We selected 1,521 studies with bulk densities in the literature, corresponding to 44 years (1977 and 2021), which were analyzed by a statistical technique that integrates the results of two or more independent studies on the same subject and combines them into a summary measure (portion forestry). From the data collected in the literature, it was possible to separate two groups of bulk density and management in clayey soils indicative of compaction: the managements that perform little or no manipulation of the soil, such as pasture and no-tillage, densities between 1.41-1.45 Mg.m-3 (average 1.43 Mg m-3), and for the others, such as conventional plowing and minimum tillage, soil densities between 1.31-1.38 Mg.m-3 (average 1.35 Mg m-3). Finally, we conclude that compaction must be analyzed considering the texture and type of soil management.(AU)

Os valores de densidade do solo indicativos de compactação em solos argilosos correspondem a uma ampla faixa de valores (1,30-1,47 Mg m-3), devido aos diversos tipos de manejo do solo. Nossa hipótese é que se considerarmos os valores de densidade do solo dentro de grupos de manejo semelhantes (os que caem no chão e os que não caem), os valores serão mais precisos dentro de cada grupo de manejo. Nosso objetivo neste trabalho foi analisar usando os conceitos de (Yates & Cochran, 1938; Whitehead, 2002) qual é uma forma estatística adequada de agrupar esses resultados para chegar a um consenso sobre uma hipótese testada, o maior número dos valores de densidade levantados entre 1977 e 2021, considerados para o estudo da compactação em Latossolos argilosos sob diferentes manejos, para verificar se nossa hipótese será confirmada. Selecionamos 1.521 estudos com densidades do solo na literatura, correspondentes a 44 anos (1977 e 2021), que foram analisados por uma técnica estatística que integra os resultados de dois ou mais estudos independentes sobre o mesmo assunto e os combina em uma medida resumida (forest plot). A partir dos dados levantados na literatura, foi possível separar dois grupos de densidade do solo e manejo em solos argilosos indicativos de compactação: os manejos que realizam pouca ou nenhuma manipulação do solo, como pastagem e plantio direto, densidades entre 1,41 -1,45 Mg.m-3 (média 1,43 Mg m-3), e para as demais, como aração convencional e preparo mínimo, densidades de solo entre 1,31-1,38 Mg.m-3 (média 1,35 Mg m-3). Por fim, concluímos que a compactação deve ser analisada considerando a textura e o tipo de manejo do solo.(AU)

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Bananas are a worldwide cultivated crop and one of the main agricultural activities in Brazil. The banana orchards cultivated in the region of São Paulo State are under native areas of the Atlantic Forest biome. The Atlantic Forest has suffered agricultural and urban pressure for many years. Banana crops require soil management and superficial vegetation removal in the first cycles. We conducted a study aiming to understand the impact of long-standing banana cultivation in the Atlantic forest region. Soil samples in banana plantations (EBP) and forest remnants (FR) were collected from trenches with 0- to 100-cm layers. The soil bulk density in EBP until 30-cm depth was 12.76% higher than that in FR. Quantifications of macropores and micropores in FR reached values higher than those in EBP. The results showed that carbon stocks decreased from the top to the deeper layers. Thirty years after the conversion, the FR treatment accumulated 28.23% more carbon than EBP. Considering our results, it was evident that changes in physical and chemical properties reflected the negative impacts of the banana plantations, cropped through conventional management, when converted from forest even in regard to a remnant one. These findings, showed for the first time, lead us to understand the soil management of banana plantations, following conventional agriculture systems, as a potential carbon stock reducer and a factor resulting in the loss of soil quality in the region. Additionally, our data can be used by environmentalists and government policymakers to promote environmental sustainability.

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Hectolitre weight (HW) is the principal quantitative parameter used by receiving units as an indicator of the quality of wheat grain (Triticum aestivum L.). The moisture content and the equipment used can be considered important sources of variation to assess a batch, requiring correct sizing of the sample used to measure the HW. This research identified the variability between the equipment used to evaluate HW with or without correcting the grain moisture content, and to estimate the ideal number of samples for the commercial classification of wheat batches. The experiment was carried out in a randomised block design with four replications. Seven batches of wheat grain from different cultivars and/or production sites were used to measure the HW using three types of equipment (Equipment 'A', Equipment 'B' and Equipment 'C'), with and without correcting the grain moisture content to 13%. Higher values for HW were determined with Equipment 'A' (77.15) compared to Equipment 'B' (75.08) and Equipment 'C' (74.69), classifying the wheat according to type. The moisture content affected the HW, but did not change the final classification of the wheat in terms of type. The ideal number of samples for HW ranged from 1 to 18 at the lowest level of precision (HW=mean±1 kg hl-¹) and from 67 to 1820 samples for the highest precision (HW=mean±0.1 kg hl-¹). Equipment 'B' requires a smaller number of samples (possibly as few as one) for the same level of precision (HW=mean±1 kg hl-¹), whereas Equipment 'A' requires a greater number of samples for the majority of batches. Correctly classifying wheat by HW therefore depends on a larger number of samples.

A massa de hectolitro (MH) é o principal parâmetro quantitativo usado nas unidades de recebimento como indicador de qualidade dos grãos de trigo (Triticum aestivum L.). O teor de umidade e o equipamento utilizado podem ser considerados fontes de variação importantes na classificação de um lote, necessitando correto dimensionamento amostral para mensuração da MH. O objetivo dessa pesquisa foi identificar a variabilidade entre equipamentos para avaliação da MH com correção ou não do teor de umidade da massa de grãos e estimar o número ideal de amostras para classificação comercial de lotes de trigo. O experimento foi realizado em delineamento experimental de blocos ao acaso com quatro repetições. Sete lotes de grãos de trigo, oriundos de diferentes cultivares e/ou locais de produção, foram usados para mensuração da MH em três equipamentos (Equipamento "A", Equipamento "B" e Equipamento "C"), com e sem correção da umidade dos grãos para 13%. Maiores valores da MH foram determinados no Equipamento "A" (77,15) comparado ao Equipamento "B" (75,08) e Equipamento "C" (74,69), com classificação distinta do trigo quanto ao tipo. O teor de umidade afetou a MH, mas não alterou a classificação final do trigo quanto ao tipo. O número ideal de amostras para MH variou de uma a 18 amostras para o menor nível de precisão (MH = média ± 1 kg hl-¹) e, de 67 a 1820 amostras para a maior precisão (MH = média ± 0,1 kg hl-¹). O Equipamento "B" requer menor número de amostras (podendo chegar a uma) para um mesmo nível de precisão (MH = média ± 1 kg hl-¹), enquanto o Equipamento "A" necessita maior número de amostras para a maioria dos lotes. Assim, a correta classificação do trigo pela MH depende de maior número de amostras.

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ABSTRACT Soil is an important carbon reservoir as it can store twice the amount that atmosphere does and three times the biomass, which makes it a key component for climate change (CC) mitigation projects. It is important to know the potential of soil organic carbon storage (SOC) in the main uses of the soli and their expected dynamics due to potential use changes. SOCS is estimated in 7 of the dominant land use systems in the area of the study, with 5 replicas as follows: 1) banana with shade (SAF+banana); 2) cocoa with shade (Ca+S); 3) citrus (C); 4) low silvopastoral system (SSPB); 5) high silvopastoral system (SSPA); 6) gallery forests (BG); and 7) bush forest (MM). SOC concentration was analyzed in samples composed of 25 soil sub-samples per plot, and the DA was estimated with the cylinder method in a simple per plot. All land uses studied can mitigate CC when storing SOC. BG was the system that showed the highest carbon storage. On the other hand, SAF+banana stored the least SOC (72,7 vs 33,4Mg/ha, respectively). Changes in land use can cause CO2 emissions or an addition in carbon fixation. Changes in land use that increase SOC allow CC mitigation, which makes them feasible for funding, thus allowing an improvement in the livelihood of local producers.

RESUMEN El suelo es un reservorio importante de carbono, ya que puede almacenar el doble de lo contenido por la atmósfera y el triple de la biomasa. Esto lo constituye en un componente clave para proyectos de mitigación del cambio climático (CC). Es importante conocer el potencial de almacenamiento de carbono orgánico del suelo (COS) en los principales usos del suelo y su dinámica esperada, por potenciales cambios de uso. Se estima el COS en los siete de los sistemas de uso del suelo dominantes en el área de estudio, con cinco réplicas, así: 1) plátano con sombrío (SAF+plátano); 2) cacao con sombrío (Ca+S); 3) cítricos (C); 4) sistema silvopastoril bajo (SSPB); 5) sistema silvopastoril alto (SSPA); 6) bosques de galería (BG) y 7) mata de monte (MM). La concentración de COS fue analizada en muestras compuestas de 25 submuestras de suelo por parcela y la DA, se estimó con el método del cilindro en una muestra por parcela. Todos los usos del suelo estudiados pueden mitigar el CC al almacenar COS. El BG fue el sistema que presentó el mayor almacenamiento de carbono; por el contrario, el SAF+plátano almacenó el menor COS (72,7 vs 33,4Mg/ha, respectivamente). Cambios de uso del suelo pueden causar emisión de CO2 o adicionalidad en la fijación de carbono. Cambios de uso del suelo que incrementen el COS permiten la mitigación del CC, pudiendo ser susceptibles de financiamiento, lo que permite mejorar los medios de vida de los productores locales.

RESUMO

The objective was to test the response of Urochloa brizantha cv. Marandu in monoculture and in silvopastoral system (SPS), at two distances from the trees, and define the best defoliation height for SPS. Four intermittent defoliation heights (25, 35, 45 and 55cm) and two distances from tree lines (2.5 and 5.0m) were evaluated in the SPS with a control defoliated with 25cm in full sun. The experiment was performed in a randomized block design with 3 replicates in a 4 × 2 + 1 split plot scheme. The control had higher forage accumulation (46.9kg/ha. day) than the SPS (31.1kg/ha. day). The bulk density was also higher in the control (0.89mg/cm³) than in SPS (0.48mg/cm³). The percentage of leaves (78.06%) and leaf/stem ratio (6.04) did not differ among the treatments. In the SPS, there was an increase of 31.07% in forage accumulation from 25 to 55cm. The forage accumulation and bulk density of Urochloa brizantha cv. Marandu in monoculture is greater than in the SPS regardless of the management goal and the distance from trees. The goal of 55cm in the SPS presented greater forage accumulation.(AU)

O objetivo foi testar a resposta de pastos de Urochloa brizantha cv. Marandu em monocultivo e em sistema silvipastoril (SSP), a diferentes distâncias das árvores, bem como definir qual altura de desfolhação é a mais indicada para manejo em SPS. Foram avaliadas quatro alturas de desfolhação intermitente (25, 35, 45 e 55cm) e duas distâncias das linhas de árvores (2,5 e 5,0m), no SPS, e uma testemunha desfolhada com 25cm, em pleno sol. O delineamento foi em blocos ao acaso, com três repetições, em esquema de parcelas subdivididas 4 × 2 + 1. O controle apresentou maior acúmulo de forragem (46,9kg/ha.dia) que a média do SSP (31,1kg/ha.dia). A densidade volumétrica da forragem do controle (0,89mg/cm³) foi maior que a do SSP (0,48mg/cm³). A porcentagem de folhas (78,06%) e a relação folha/colmo (6,04) não diferiram entre os tratamentos. O aumento das alturas de 25 para 55cm no SSP resultou em aumento de 31,07% no acúmulo de forragem. O acúmulo e a densidade volumétrica da forragem são maiores no monocultivo, independentemente da meta de manejo e da distância das árvores no sistema silvipastoril. A meta de 55cm no silvipastoril apresenta maior acúmulo de forragem.(AU)

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Cover crops promote nutrient cycling, and lime and gypsum can alter the soil physical attributes. This study aimed to evaluate the effect of lime and gypsum rates applied to a no-tillage system with addition of residues of three cover crops on the soil physical attributes. This experiment was carried out in chapadão do sul-ms. The treatments were comprised of three cover crops (Urochloa ruziziensis, fallow, and Pennisetum glaucum), with gypsum (0, 2.3 and 4.6 Mg ha-1) and lime applied at a dose of 0, 2, 4, 6 Mg ha-1).The attributes evaluated were: soil density, macroporosity, microporosity, total porosity and penetration resistance. The soil of the experiment was classified an Oxisol. Cover crops and lime and gypsum improved macroporosity, microporosity and total porosity at all depths, 0-0.2 m. Millet presented lower values for penetration resistance with the lime application and without gypsum application. No residual effect on soil density was detected for lime and gypsum application or cover crops in the 0.1-0.2 m layer. Brazilian Cerrado producers will have a well-defined management system to follow aiming at improving the soil physical attributes.

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Beans are the main source of protein of plant origin in the Brazilian diet, they also contain phenolic compounds, antioxidants, iron, fibers and vitamins. The BRSMG Majestoso cultivar belongs to the commercial group of carioca beans, displays high productivity, excellent health and a 90-day cycle, has high yield and is resistant to disease. The study of physical properties enables the prediction of agricultural products behavior relative to responses of physical and chemical treatments, in order to allow the maintenance of quality and safety of processed foods. The aim of the present study was to evaluate the effect of drying on the physical characteristics of beans of the BRSMG Majestoso cultivar. Beans with an initial moisture content of approximately 0.2660 d.b. (dry basis) were used, and dried at 40ºC. The following physical characteristics were determined: bulk density, unit density, intergranular porosity, 1000-grain weight, sphericity, circularity, geometric diameter, unit volume, projected area, surface area and the surface to volume ratio. Based on the results, a reduction in the moisture content of the beans promotes an increase in bulk density, unit density, porosity, sphericity, circularity and the surface to volume ratio. Conversely, the 1000-grain weight, geometric diameter, unit volume, projected area and surface area decreased as the moisture content of the beans was reduced.

Objetivou-se com o presente trabalho, avaliar o efeito da secagem sobre as características físicas de grãos de feijão cultivar BRSMG Majestoso. Foram utilizados grãos com teor de água inicial de aproximadamente 0,2660 b.s. (base seca), e submetidos à secagem com temperatura de 40 ºC. Foram determinadas as propriedades físicas: massa específica aparente, massa específica unitária, porosidade intergranular, massa de mil grãos, esfericidade, circularidade, diâmetro geométrico, volume unitário, área projetada, área superficial e a relação superfície/volume. Com base nos resultados obtidos conclui-se que a redução do teor de água dos grãos de feijão proporcionou aumento da massa específica aparente e unitária, porosidade, esfericidade, circularidade e relação superfície/volume. Em contrapartida, a massa de mil grãos, o diâmetro geométrico, o volume unitário, a área projetada e a área superficial diminuíram com a redução do teor de água dos grãos de feijão.

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The structure of the sward is important because it influences the responses of plants and animals in grazing conditions. The objective with this work was to evaluate the structural characteristics of the Marandu palisade grass pasture (Brachiaria brizantha syn. Urochloa brizantha) during spring and summer, depending on the condition of the sward at the end of winter. Four grazing conditions at the end of winter were evaluated: short (24.1 cm), short (25.2 cm)/mown (8 cm), tall (49.0 cm) and tall (50.0 cm)/mown (8 cm). The foliar area index was lower in the tall pasture than in the tall/mown pasture. The mass and the volumetric density of dead stem were higher in the tall pasture, intermediate in the short pasture, and lower in mowed pastures. At the beginning of the grazing period, the live stem mass was higher in the tall pasture. At the beginning and middle of the grazing period, the volumetric density of dead leaf lamina was lower in mowed pastures. At the beginning of the pasture period, the short pasture had a higher tiller number (TN). In the middle of the grazing period, the short and short/mown pastures had higher TN. At the end of the pasture period, the lowest TN value occurred in the tall pasture. The tall pasture at the end of winter presents an unfavorable structure to the animal in grazing, while the mowing and reduction in the height of the marandu palisade grass improves the structure of the sward in spring and summer.

A estrutura do pasto é importante porque influencia as respostas de plantas e animais em condições de pastejo. O objetivo com este trabalho foi avaliar as características estruturais do pasto de capim-marandu (Brachiaria brizantha syn. Urochloa brizantha) durante a primavera e o verão, em função da condição do pasto no fim do inverno. Quatro condições de pasto no fim do inverno foram avaliadas: baixo (24,1 cm), baixo (25,2 cm)/roçado (8 cm), alto (49,0 cm) e alto (50,0 cm)/roçado (8 cm). O índice de área foliar foi menor no pasto alto do que no pasto alto/roçado. A massa e a densidade volumétrica de colmo morto foram maiores no pasto alto, intermediárias no pasto baixo, e inferiores nos pastos roçados. No início do período de pastejo, a massa de colmo vivo foi maior no pasto alto. No início e meio do período de pastejo, a densidade volumétrica de lâmina foliar morta foi menor nos pastos roçados. No início do período de pastejo, o pasto baixo apresentou maior número de perfilho (NP). No meio do período de pastejo, os pastos baixo e baixo/roçado tiveram maior NP. No fim do período de pastejo, o menor valor de NP ocorreu no pasto alto. O pasto alto no fim do inverno apresenta estrutura desfavorável ao animal em pastejo, enquanto que a roçada e a redução da altura do capim-marandu melhora a estrutura do pasto na primavera e no verão.

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The effects of soil compaction on porosity (α), bulk density (ρs), and saturated hydraulic conductivity (Ksat) can create a physical barrier in the soil, reducing the vertical movement of toxic elements in the soil profile. However, the indirect effects of compaction in altering the forms and availability of heavy metals in soil have not been well-studied. This study examined the influence of compaction on forms of lead (Pb) in soils with contrasting texture. Four levels of compaction were imposed on a sandy loam and a clayey soil, which were artificially contaminated based on their maximum Pb adsorption capacity. Compaction had different effects on Pb forms depending on soil texture. In the sandy loam soil, compaction had a dual beneficial effect in mitigating the impact of Pb contamination, since it decreased Ksat, reducing metal transport to deeper soil layers, and also prevented transformation to more available Pb forms (soluble and exchangeable). Instead, there was an increase in the most environmentally stable forms of Pb (inner sphere adsorption on iron and manganese oxides). In the clayey soil, compaction caused a significant increase in soluble and exchangeable Pb, accompanied by a significant reduction in environmentally stable Pb (inner sphere adsorption on gibbsite and kaolinite). In addition, studies about Pb contents under compacted soil layers should be investigated, mainly in clayey soils with edible crops, and environmental remediation practices that involve the machines traffic (for example, phytoremediation-successive cultivation of Pb-hyperaccumulating plants) should be used with care to minimise the compaction of clayey soils.

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The deferred pasture structure determines the consumption and performance of grazing animals and, in addition, can be influenced by the duration of the deferment period and nitrogen (N) fertilisation. The objective of this work was to evaluate the structural characteristics of Brachiaria brizantha syn. Urochloa brizantha cv. Piatã (piatã palisadegrass) deferred for two periods (79 and 127 days) and with four N doses (0, 40, 80 and 120 kg ha-1) in the Zona da Mata of Minas Gerais, Brazil. The experimental design involved complete randomised blocks and a subdivided plot scheme, with three replications. The 127-day period of deferment resulted in a higher forage mass, falling index, stem percentage and density, but a lower number of tillers, percentage and volumetric density of live leaf blade. The N dose increment, in general, worsened the structural characteristics of the piatã palisadegrass deferred for 127 days. However, with the 79-day period, the N fertilisation increased the volumetric density of live leaf blades and reduced the stem percentage in the forage mass. As a preliminary recommendation, piatã palisadegrass can be deferred for 79 days and fertilised with up to 90 kg ha-1 of N in the region of Zona da Mata de Minas Gerais, Brazil.

A estrutura do pasto diferido determina o consumo e o desempenho dos animais em pastejo e, ademais, pode ser influenciada pela duração do período de diferimento e pela adubação nitrogenada. O objetivo com este trabalho foi avaliar as características estruturais da Brachiaria brizantha syn. Urochloa brizantha cv. Piatã (capim-piatã) diferida por dois períodos (79 e 127 dias) e com quatro doses de nitrogênio (0, 40, 80 e 120 kg ha-1) na Zona da Mata de Minas Gerais, Brasil. O experimento foi em blocos completos casualizados e em esquema de parcela subdividida, com três repetições. O período de 127 dias de diferimento resultou em maiores massa de forragem, índice de tombamento, porcentagem e densidade volumétrica de colmo, porém em menores número de perfilho, porcentagem e densidade volumétrica de lâmina foliar viva. O incremento da dose de N reduziu a porcentagem de lâmina foliar viva na massa de forragem do capim-piatã diferido por 127 dias. Porém, com o período de 79 dias, a adubação aumentou a densidade volumétrica de lâmina foliar viva e reduziu a porcentagem de colmo na massa de forragem. Como recomendação preliminar, o capim-piatã pode ser diferido por 79 dias e com adubação de até 90 kg ha-1 de N na região da Zona da Mata de Minas Gerais, Brasil.

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The deferred pasture structure determines the consumption and performance of grazing animals and, in addition, can be influenced by the duration of the deferment period and nitrogen (N) fertilisation. The objective of this work was to evaluate the structural characteristics of Brachiaria brizantha syn. Urochloa brizantha cv. Piatã (piatã palisadegrass) deferred for two periods (79 and 127 days) and with four N doses (0, 40, 80 and 120 kg ha-1) in the Zona da Mata of Minas Gerais, Brazil. The experimental design involved complete randomised blocks and a subdivided plot scheme, with three replications. The 127-day period of deferment resulted in a higher forage mass, falling index, stem percentage and density, but a lower number of tillers, percentage and volumetric density of live leaf blade. The N dose increment, in general, worsened the structural characteristics of the piatã palisadegrass deferred for 127 days. However, with the 79-day period, the N fertilisation increased the volumetric density of live leaf blades and reduced the stem percentage in the forage mass. As a preliminary recommendation, piatã palisadegrass can be deferred for 79 days and fertilised with up to 90 kg ha-1 of N in the region of Zona da Mata de Minas Gerais, Brazil.(AU)

A estrutura do pasto diferido determina o consumo e o desempenho dos animais em pastejo e, ademais, pode ser influenciada pela duração do período de diferimento e pela adubação nitrogenada. O objetivo com este trabalho foi avaliar as características estruturais da Brachiaria brizantha syn. Urochloa brizantha cv. Piatã (capim-piatã) diferida por dois períodos (79 e 127 dias) e com quatro doses de nitrogênio (0, 40, 80 e 120 kg ha-1) na Zona da Mata de Minas Gerais, Brasil. O experimento foi em blocos completos casualizados e em esquema de parcela subdividida, com três repetições. O período de 127 dias de diferimento resultou em maiores massa de forragem, índice de tombamento, porcentagem e densidade volumétrica de colmo, porém em menores número de perfilho, porcentagem e densidade volumétrica de lâmina foliar viva. O incremento da dose de N reduziu a porcentagem de lâmina foliar viva na massa de forragem do capim-piatã diferido por 127 dias. Porém, com o período de 79 dias, a adubação aumentou a densidade volumétrica de lâmina foliar viva e reduziu a porcentagem de colmo na massa de forragem. Como recomendação preliminar, o capim-piatã pode ser diferido por 79 dias e com adubação de até 90 kg ha-1 de N na região da Zona da Mata de Minas Gerais, Brasil.(AU)

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Concerns about the negative effects of agriculture on soil physical quality and soil organic carbon (SOC) pools have spurred on the adoption of conservation tillage systems in tropical regions. This study aimed to evaluate the long-term impacts (16th year) of conventional (CT), minimum (MT) and no-tillage (NT) practices and different cover crops (sunn hemp and a bean/millet sequence) on soil physical properties and SOC content of a corn cultivated Ultisol in the northeast of Brazil. Soil bulk density (Bd), soil penetration resistance (SPR), soil aggregation, and total aggregate-associated carbon (C) (4-2 mm) were evaluated. Tillage practices exerted strong control on soil physical properties and total aggregate-C content but were influenced by cover crop species. Minimum tillage presented the lowest Bd, irrespective of cover crop, while NT with bean/millet sequence resulted in the lowest SPR. However, as regards soil aggregation and total aggregate-C, the results indicated that there were no differences between MT and NT, with both systems presenting greater mean weight diameter (MWD) and total aggregate-C content than CT. Total aggregate-C content in the 0.00-0.05 m soil layer in conservation tillage was increased by the adoption of a bean/millet sequence. Increased mechanical disturbance through CT practices was harmful to Bd, soil aggregation and SOC accrual. Overall, more conservative tillage practices and the proper choice of cover crops might yield greater soil quality. Low intensity of soil disturbances due to the adoption of MT favors soil aggregation and the accrual of SOC in weakly structured soils through increases in contact between organic and mineral particles while not causing significant destruction of soil aggregates.(AU)

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Concerns about the negative effects of agriculture on soil physical quality and soil organic carbon (SOC) pools have spurred on the adoption of conservation tillage systems in tropical regions. This study aimed to evaluate the long-term impacts (16th year) of conventional (CT), minimum (MT) and no-tillage (NT) practices and different cover crops (sunn hemp and a bean/millet sequence) on soil physical properties and SOC content of a corn cultivated Ultisol in the northeast of Brazil. Soil bulk density (Bd), soil penetration resistance (SPR), soil aggregation, and total aggregate-associated carbon (C) (4-2 mm) were evaluated. Tillage practices exerted strong control on soil physical properties and total aggregate-C content but were influenced by cover crop species. Minimum tillage presented the lowest Bd, irrespective of cover crop, while NT with bean/millet sequence resulted in the lowest SPR. However, as regards soil aggregation and total aggregate-C, the results indicated that there were no differences between MT and NT, with both systems presenting greater mean weight diameter (MWD) and total aggregate-C content than CT. Total aggregate-C content in the 0.00-0.05 m soil layer in conservation tillage was increased by the adoption of a bean/millet sequence. Increased mechanical disturbance through CT practices was harmful to Bd, soil aggregation and SOC accrual. Overall, more conservative tillage practices and the proper choice of cover crops might yield greater soil quality. Low intensity of soil disturbances due to the adoption of MT favors soil aggregation and the accrual of SOC in weakly structured soils through increases in contact between organic and mineral particles while not causing significant destruction of soil aggregates.

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RESUMO

Os sistemas integrados de produção agropecuária visam a sustentabilidade, procurando explorar o máximo da área, além de diminuir os impactos sobre as propriedades do solo. O presente trabalho teve objetivo estudar a distribuição do tamanho de poros de um Latossolo Vermelho em um sistema integrado de produção agropecuária após três anos de implantação do sistema. O experimento foi realizado na Fazenda pertencente ao grupo Facholi, no município de Caiuá/SP. O delineamento experimental utilizado foi em blocos casualizados, com três repetições e compostos por 7 tratamentos: 1 - Soja–Milho + B. ruziziensis (pastejo); 2 - Soja – Milho + Piatã (pastejo); 3 - Soja – Milho + Paiaguás (pastejo); 4 - Soja - Piatã (pastejo 2 anos) – Soja - Piatã (pastejo); 5 - Soja - Paiaguás (pastejo 2 anos) – Soja - Paiaguás (pastejo); 6 -Soja – milho (Plantio direto); 7 - Soja – milho (Preparo convencional). Foram realizadas as avaliações dos seguintes atributos do solo: macroporosidade, microporosidade, porosidade total e densidade do solo, em duas camadas do solo; 0,00-0,10 e 0,10-0,20 m de profundidade, em três épocas de coleta, utilizando o teste Tukey a 5% de probabilidade para a comparação de médias. Os resultados mostram que a macroporosidade aumentou com o tempo (3 anos de avaliação), e houve uma diminuição da densidade do solo, mostrando que os sistemas avaliados influenciaram positivamente os atributos do solo estudados. De forma geral, todos ao tratamentos aumentaram a macroporosidade em relação a caracterização inicial, com destaque para os tratamentos soja+piatã e soja+milho+piatã, camada de 0-0,10m que obtiveram valores médios superiores aos demais.

Integrated agricultural production systems aim at sustainability, seeking to exploit the maximum of the area, as well as reducing impacts on soil properties. The objective of this work was to study the distribution of pore size of an Oxisol in an integrated agricultural production system after three years of system implantation. The experiment was carried out at Fazenda belonging to the Facholi group, in the municipality of Caiuá / SP. The experimental design was a randomized complete block with three replicates and composed of 7 treatments: 1 - Soya - Maize + B. ruziziensis (grazing); 2 - Soybean - Maize + Piatã (grazing); 3 -Soya - Maize + Paiaguás (grazing); 4 - Soya - Piatã (grazing 2 years) - Soya - Piatã (grazing); 5 - Soybean - Paiaguás (grazing 2 years) - Soybean - Paiaguás (grazing); 6 - Soybean - maize (Direct planting); 7 - Soybean - corn (Conventional preparation). The following soil attributes were evaluated: macroporosity, microporosity, total porosity and soil density in two depths of soil; 0.00-0.10 and 0.10-0.20 m depth, in three sampling periods, using the Tukey test at 5% probability for the comparison of means. The results show that the macroporosity increased with time(3 years of evaluation), and there was a decrease in soil density, showing that the evaluated systems positively influenced the soil attributes studied. In general, all treatments increased the macroporosity in relation to the initial characterization, especially the soybean + piatan and soy + maize + piatã treatments, 0-0.10 m depth, which obtained higher, average values than the others.

Assuntos

RESUMO

Os sistemas integrados de produção agropecuária visam a sustentabilidade, procurando explorar o máximo da área, além de diminuir os impactos sobre as propriedades do solo. O presente trabalho teve objetivo estudar a distribuição do tamanho de poros de um Latossolo Vermelho em um sistema integrado de produção agropecuária após três anos de implantação do sistema. O experimento foi realizado na Fazenda pertencente ao grupo Facholi, no município de Caiuá/SP. O delineamento experimental utilizado foi em blocos casualizados, com três repetições e compostos por 7 tratamentos: 1 - Soja–Milho + B. ruziziensis (pastejo); 2 - Soja Milho + Piatã (pastejo); 3 - Soja Milho + Paiaguás (pastejo); 4 - Soja - Piatã (pastejo 2 anos) Soja - Piatã (pastejo); 5 - Soja - Paiaguás (pastejo 2 anos) Soja - Paiaguás (pastejo); 6 -Soja milho (Plantio direto); 7 - Soja milho (Preparo convencional). Foram realizadas as avaliações dos seguintes atributos do solo: macroporosidade, microporosidade, porosidade total e densidade do solo, em duas camadas do solo; 0,00-0,10 e 0,10-0,20 m de profundidade, em três épocas de coleta, utilizando o teste Tukey a 5% de probabilidade para a comparação de médias. Os resultados mostram que a macroporosidade aumentou com o tempo (3 anos de avaliação), e houve uma diminuição da densidade do solo, mostrando que os sistemas avaliados influenciaram positivamente os atributos do solo estudados. De forma geral, todos ao tratamentos aumentaram a macroporosidade em relação a caracterização inicial, com destaque para os tratamentos soja+piatã e soja+milho+piatã, camada de 0-0,10m que obtiveram valores médios superiores aos demais.(AU)

Integrated agricultural production systems aim at sustainability, seeking to exploit the maximum of the area, as well as reducing impacts on soil properties. The objective of this work was to study the distribution of pore size of an Oxisol in an integrated agricultural production system after three years of system implantation. The experiment was carried out at Fazenda belonging to the Facholi group, in the municipality of Caiuá / SP. The experimental design was a randomized complete block with three replicates and composed of 7 treatments: 1 - Soya - Maize + B. ruziziensis (grazing); 2 - Soybean - Maize + Piatã (grazing); 3 -Soya - Maize + Paiaguás (grazing); 4 - Soya - Piatã (grazing 2 years) - Soya - Piatã (grazing); 5 - Soybean - Paiaguás (grazing 2 years) - Soybean - Paiaguás (grazing); 6 - Soybean - maize (Direct planting); 7 - Soybean - corn (Conventional preparation). The following soil attributes were evaluated: macroporosity, microporosity, total porosity and soil density in two depths of soil; 0.00-0.10 and 0.10-0.20 m depth, in three sampling periods, using the Tukey test at 5% probability for the comparison of means. The results show that the macroporosity increased with time(3 years of evaluation), and there was a decrease in soil density, showing that the evaluated systems positively influenced the soil attributes studied. In general, all treatments increased the macroporosity in relation to the initial characterization, especially the soybean + piatan and soy + maize + piatã treatments, 0-0.10 m depth, which obtained higher, average values than the others.(AU)

Assuntos

RESUMO

The aim of this study was to evaluate the morphological and structural characteristics of deferred Urochloa decumbens Stapf. ‘Basilisk’ grazed by Nellore heifers under two periods of protein and energy supplementation (PES). The experiment was carried out from Jun 21 to Nov 15, 2016, under a completely randomized design and two PES periods (55 [P55] and 147 [P147] days). Forage mass (FM), leaf blade dry mass (LBDM), stem dry mass (SDM), dead material dry mass (DMDM), canopy height (CH), and forage bulk density (FBD) were evaluated. Data were analyzed by the SAS® PROC MIXED procedure and treatment means were compared with the Student's t test (p < 0.05). LBDM was higher for P147 heifers after 21, 84, and 126 days of grazing, similar to those observed after 63 days, and was higher for P55 heifers at 42, 105, and 147 days of grazing. SDM was lower for P147 heifers after 21, 42, 105, and 126 days, and similar in the other grazing periods. Protein and energy supplementation for heifers over 147 days resulted in a lower stem mass of U. decumbens Stapf. ‘Basilisk’ deferred pastures.

Assuntos

RESUMO

The aim of this study was to evaluate the morphological and structural characteristics of deferred Urochloa decumbens Stapf. ‘Basilisk grazed by Nellore heifers under two periods of protein and energy supplementation (PES). The experiment was carried out from Jun 21 to Nov 15, 2016, under a completely randomized design and two PES periods (55 [P55] and 147 [P147] days). Forage mass (FM), leaf blade dry mass (LBDM), stem dry mass (SDM), dead material dry mass (DMDM), canopy height (CH), and forage bulk density (FBD) were evaluated. Data were analyzed by the SAS® PROC MIXED procedure and treatment means were compared with the Student's t test (p < 0.05). LBDM was higher for P147 heifers after 21, 84, and 126 days of grazing, similar to those observed after 63 days, and was higher for P55 heifers at 42, 105, and 147 days of grazing. SDM was lower for P147 heifers after 21, 42, 105, and 126 days, and similar in the other grazing periods. Protein and energy supplementation for heifers over 147 days resulted in a lower stem mass of U. decumbens Stapf. ‘Basilisk deferred pastures.(AU)

Assuntos

RESUMO

A compactação do solo constitui um fator limitante ao crescimento e desenvolvimento vegetativo, reduzindo a produtividade agrícola. Neste contexto, objetivou-se com o presente trabalho, avaliar os efeitos da profundidade da camada compactada e do nível de compactação de um Latossolo Vermelho-Amarelo distrófico no crescimento de plântulas de milho. O delineamento experimental foi inteiramente casualizado, em parcelas subdividas no tempo, disposto em um esquema fatorial 2×2 + 1, sendo duas densidades do solo (1,5 e 1,7 g cm-3), duas profundidades da camada compactada (0 -3 cm e 8 -11 cm) e um controle com densidade natural do solo (1,3 g cm-3), com três repetições. Foi cultivado o milho híbrido AG 1051 em colunas durante o período de 38 dias. Durante o período experimental, foram avaliados: a área foliar (AF), o número de folhas (NF), o diâmetro do caule (DC), comprimento do caule (CC), volume radicular (VR), massa seca foliar (MSF), do caule (MSC) e das raízes (MSR), a taxa de crescimento absoluto (TCA) e relativo (TCR). De acordo com os resultados obtidos, o aumento da densidade do solo promoveu alterações morfológicas no diâmetro do caule (DC), e no volume da raiz (VR), e, consequentemente, na massa seca da raiz (MSR) e massa seca total (MST). A compactação na camada superficial é mais prejudicial ao crescimento da cultura do que na camada subsuperficial.

Soil compaction is a limiting factor to growth and vegetative development, reducing agricultural productivity. In this context, the aim of the present study was to evaluate the effects of the depth of the compacted layer and the level of compaction of a Dystrophic Red-Yellow Oxisol on the growth of maize seedlings. The experimental design was completely randomized in split plots in time, arranged in a factorial 2 ×2 + 1, being two soil densities (1.5 and 1.7 g cm-3), two layers of compacted layer (0 -3 cm and 8 -11 cm) and a control with natural soil density (1.3 g cm-3), with three replications. Hybrid maize AG 1051 were cultivated in columns, over the period of 31 days. During the trial period, were evaluated: the leaf area (LA), the number of leaves (NL), stem diameter (SD), stem length (SL), root volume (RV), leaves dry matter (LDM), stem (SDM) and root (RDM), the absolute growth rate (AGR) and relative (RGR). According to the results, the increase in soil density promoted morphological changes in stem diameter, and the volume of the root, and consequently, the root dry mass and total dry matter. The compression in the surface layer is more harmful to crop growth than in the subsurface layer.

RESUMO

A compactação do solo constitui um fator limitante ao crescimento e desenvolvimento vegetativo, reduzindo a produtividade agrícola. Neste contexto, objetivou-se com o presente trabalho, avaliar os efeitos da profundidade da camada compactada e do nível de compactação de um Latossolo Vermelho-Amarelo distrófico no crescimento de plântulas de milho. O delineamento experimental foi inteiramente casualizado, em parcelas subdividas no tempo, disposto em um esquema fatorial 2×2 + 1, sendo duas densidades do solo (1,5 e 1,7 g cm-3), duas profundidades da camada compactada (0 -3 cm e 8 -11 cm) e um controle com densidade natural do solo (1,3 g cm-3), com três repetições. Foi cultivado o milho híbrido AG 1051 em colunas durante o período de 38 dias. Durante o período experimental, foram avaliados: a área foliar (AF), o número de folhas (NF), o diâmetro do caule (DC), comprimento do caule (CC), volume radicular (VR), massa seca foliar (MSF), do caule (MSC) e das raízes (MSR), a taxa de crescimento absoluto (TCA) e relativo (TCR). De acordo com os resultados obtidos, o aumento da densidade do solo promoveu alterações morfológicas no diâmetro do caule (DC), e no volume da raiz (VR), e, consequentemente, na massa seca da raiz (MSR) e massa seca total (MST). A compactação na camada superficial é mais prejudicial ao crescimento da cultura do que na camada subsuperficial.(AU)

Soil compaction is a limiting factor to growth and vegetative development, reducing agricultural productivity. In this context, the aim of the present study was to evaluate the effects of the depth of the compacted layer and the level of compaction of a Dystrophic Red-Yellow Oxisol on the growth of maize seedlings. The experimental design was completely randomized in split plots in time, arranged in a factorial 2 ×2 + 1, being two soil densities (1.5 and 1.7 g cm-3), two layers of compacted layer (0 -3 cm and 8 -11 cm) and a control with natural soil density (1.3 g cm-3), with three replications. Hybrid maize AG 1051 were cultivated in columns, over the period of 31 days. During the trial period, were evaluated: the leaf area (LA), the number of leaves (NL), stem diameter (SD), stem length (SL), root volume (RV), leaves dry matter (LDM), stem (SDM) and root (RDM), the absolute growth rate (AGR) and relative (RGR). According to the results, the increase in soil density promoted morphological changes in stem diameter, and the volume of the root, and consequently, the root dry mass and total dry matter. The compression in the surface layer is more harmful to crop growth than in the subsurface layer.(AU)

RESUMO

The development and improvement of fruit processing technologies in powder form is a alternative to add value to the product and increase the income of the producers, being required the knowledge of physicalchemical properties of the product. The aim of this study was to determine the physical-chemical properties of soursop powder obtained by foam-mat drying. To the foam formation, albumin was added to the pulp at concentration of 7.43% in mass and subjected in mixer for 15 min; then, it was spread onto trays forming a thin layer about 5.0 mm thick, and the drying conditions were: 40, 50, 60, 70 and 80 °C, 5.6 m s-1 and 60%. Moisture content, water activity, titratable total acidity and hydrogenic potential of soursop powder indicate good stability of the product obtained by foam-mat drying, without the need of addition of preservatives for its conservation. Reducing sugars increased with increasing drying temperature due to the concentration of the compounds caused by moisture content reduction. In addition, the color was the physical-chemical property that presented greater sensitivity to drying, mainly by darkening index. Temperatures lower than 60 °C indicate higher preservation of initial characteristics for soursop powder. Besides that, bulk density, true density, porosity and repose angle increased subtly with drying temperature.

O desenvolvimento e aperfeiçoamento de tecnologias de processamentos de frutos na forma de pó é uma alternativa para agregar valor ao produto e aumentar a renda dos produtores, sendo necessário para isso o conhecimento das propriedades físico-químicas do produto. Assim objetivou-se determinar as propriedades físicoquímicas do pó de graviola obtido pelo método de secagem em leito de espuma. Para a formação da espuma foi adicionada, à polpa, albumina, na concentração de 7,43% em massa e submetida à agitação em batedeira doméstica, durante 15 min; em seguida, esta foi espalhada sobre bandejas formando uma camada fina de cerca de 5,0 mm de espessura cujas condições de secagem foram: de 40, 50, 60, 70 e 80 °C, 5,6 m s-1 e 60%. O teor de água, atividade de água, acidez total titulável e o potencial hidrogeniônico do pó de graviola indicam boa estabilidade do produto obtido pelo método de secagem em leito de espuma, não necessitando portanto, da adição de conservantes para sua conservação. Os açúcares aumentaram com o incremento da temperatura de secagem devido a concentração dos compostos provocada pela redução do teor de água. Adicionalmente, a cor foi a propriedade físico-química que apresentou maior sensibilidade à secagem, principalmente pelo índice de escurecimento. Temperaturas menores que 60 °C indicam maior preservação das características iniciais para o pó de graviola. Além disso, a massa específica aparente e unitária, a porosidade e o ângulo de repouso aumentaram sutilmente com a temperatura de secagem.

Assuntos