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SUMMARYSoils are the foundation of terrestrial ecosystems and their role in food production is fundamental, although physical degradation has been observed in recent years, caused by different cultural practices that modify structures and consequently the functioning of soils. The objective of this study was to evaluate possible structural changes and degradation in an Oxisol under different managements for 20 years: no-tillage cultivation with and without crop rotation, perennial crop and conventional tillage, plus a forested area (reference). Initially, the crop profile was described and subsequently, 10 samples per management system and forest soil were collected to quantify soil organic matter, flocculation degree, bulk density, and macroporosity. The results indicated structural changes down to a soil depth of 50 cm, with predominance of structural units ∆µ ∆µ ∆µ ∆µ ∆µ (intermediate compaction level) under perennial crop and no-tillage crop rotation, and of structural units ∆ ∆ ∆ ∆ ∆ (compacted) under conventional tillage and no-tillage. The soil was increasingly degraded in the increasing order: forest => no-tillage crop rotation => perennial crop => no-tillage without crop rotation => conventional tillage. In all managements, the values of organic matter and macroporosity were always below and bulk density always above those of the reference area (forest) and, under no-tillage crop rotation and perennial crop, the flocculation degree was proportionally equal to that of the reference area.Index terms: crop profile, soil physical properties, organic matter, soil quality. RESUMO: MUDANÇAS ESTRUTURAIS E DEGRADAÇÃO DE ATRIBUTOS DE LATOSSOLO VERMELHO SUBMETIDO A DIFERENTES MANEJOS POR 20 ANOSO solo integra os ecossistemas terrestres e o papel dele na produção de alimentos é essencial, embora nos últimos anos tenha se constatado sua degradação física em razão das diferentes práticas culturais utilizadas que modificam sua estrutura e, consequentemente, seu funcionamento. O objetivo deste trabalho foi avaliar possíveis mudanças estruturais, bem como a degradação de Latossolo Vermelho submetido a diferentes manejos por 20 anos. As avaliações foram realizadas em diferentes manejos: semeadura direta com e sem rotação de culturas; cultura perene; e preparo convencional, além de uma área de mata (referência). Inicialmente, fez-se a descrição do perfil cultural e, na sequência, coletaram-se 10 amostras de solo em cada manejo considerado e sob mata nativa para quantificar o teor de matéria orgânica, o grau de floculação, a densidade e a macroporosidade do solo. Os resultados indicaram mudanças estruturais até 50 cm de profundidade com predomínio de unidades estruturais ∆µ (nível intermediário de compactação) nos manejos cultura perene e semeadura direta com rotação de culturas e unidades estruturais ∆ (compactado), nos manejos preparo convencional e semeadura direta. A degradação do solo, da menor para a maior, ocorreu na seguinte ordem: Mata => semeadura direta com rotação de culturas => cultura perene => semeadura dir...

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The soil particles can be gathered through physical and/or chemical processes in association with the biological activity, leading to the formation of aggregates. Soil aggregates has several functions in the soil, increasing macroporosity and water circulation -consequently reducing soil erosion and mechanical resistance to root growth, contributing to greater fixation of plants to the soil and absorption of water and nutrients, and protection of intra-aggregate organic matter. The aggregates were initially classified morphologically and in terms of their stability. In recent years, another way of evaluating aggregates, regarding their formation or origin pathway, has gained prominence in the studies conducted in Brazil. As for their origin, the aggregates can be classified morphologically as physicogenic, biogenic, or intermediate. This manuscript presents the techniques used to sample aggregates, the morphological patterns for their distinction observed in different soil classes and management types, and the chemical and physical properties. Additionally, we present analyses that are not commonly used to evaluate aggregates but which have the potential to be used as tools for a better understanding of their origin and to evaluate their modifications when subject to different types of management. In practical terms, identifying the aggregate origin and determining the related attributes allows recognizing the effect of vegetation/soil/management on soil aggregate forming agents, mainly roots and soil fauna, which reflects soil quality. For future studies, and especially to determine the importance of biogenic aggregation in improving edaphic properties, we suggest the use of micromorphology, near-infrared spectroscopy, X-ray computed tomography, clay dispersion analyses in addition with chemical, physical, and biological analysis. This approach can contribute to the identification of other patterns related to pedogenesis and the pathways of aggregate formation.

RESUMOA falta de estudos que indiquem as necessidades nutricionais de muitas orquídeas resulta na realização de práticas de adubação embasadas em experiências práticas e que não necessariamente atendem às demandas nutricionais de todas as espécies. O objetivo deste trabalho foi avaliar a influência da adubação mineral e orgânica e suas respectivas combinações no desenvolvimento da orquídea Cattlianthe 'Chocolate drop'. As mudas desse híbrido foram obtidas por clonagem in vitro, e cultivadas em condição de casa de vegetação, utilizando potes plásticos com capacidade de 1 L contendo como substrato uma mistura de casca de pinus e carvão (4v:3v). Os tratamentos avaliados foram: sem adubação (testemunha), fertirrigação com fertilizante mineral ultra solúvel (FMU), mistura de torta de mamona e farinha de ossos (TM+FO), bokashi (BOK), FMU + mistura de torta de mamona e farinha de ossos [FMU+(TM+FO)], FMU + bokashi (FMU+BOK), mistura de torta de mamona e farinha de ossos + bokashi [(TM+FO)+BOK], FMU + mistura de torta de mamona e farinha de ossos + bokashi [FMU+(TM+FO)+BOK]. Após oito meses do início das adubações foram avaliados o desenvolvimento da parte aérea e o acúmulo de nutrientes. O tratamento FMU+BOK foi significativamente superior ao tratamento sem adubação, com incrementos aproximados de 54, 42, 33 e 78% da massa seca da parte aérea, comprimento da parte aérea, comprimento médio radicular e área foliar, respectivamente. A combinação entre adubação mineral e orgânica favoreceu o desenvolvimento de plantas do híbrido de Cattlianthe 'Chocolate drop'.Palavras-chave: Orchidaceae, nutrição, fertilização, parte aérea, desenvolvimento vegetativo. ABSTRACT Mineral and organic fertilization influence on the development of Cattlianthe 'Chocolate drop'The lack of studies showing nutritional requirements of many orchids results in adoption of fertilization practices based on practical experience, which may not meet the nutritional requirements of all species. The objective of this study was to evaluate the influence of mineral and organic fertilizers and their combinations on growth of orchid Cattlianthe 'Chocolate drop'. Seedlings of this hybrid were obtained by in vitro cloning, and grown in a greenhouse condition using plastic pots with capacity of 1 L containing as substrate a mixture of pine and bark (4v:3v). The evaluated treatments were: without fertilization (control), ultra-soluble mineral fertilizer ( Eight months after beginning of fertilizations, development of the aboveground part and accumulation of nutrients were evaluated. The FMU+BOK treatment was significantly superior to treatment without fertilization, with approximate increments of 54, 42, 33 and 78% over the dry weight of the aboveground part, aboveground part length, root length and leaf area, respectively. The combination of mineral and organic fertilization favored the growth of hybrid plants of Cattlianthe 'Chocolate drop'.

Purpose Many studies evaluate the effect of successive applications of chicken manure on soil attributes. In Brazil, the commercialization of this waste is common, implying on its sporadic use instead of many applications at the same area. The short-term effects of a single application of chicken manure and the role of its composting on soil structural stability are not fully understood. This study investigated application of in natura (uncomposted) and composted chicken manure on the structural stability of a Rhodic Ferralsol after a short period following single application. Methods The experiment was performed in a Rhodic Ferralsol in Londrina, Paraná. Brazil. We applied in natura and composted chicken manure at doses of 4.5, 9.0, 13.5, and 18.0 Mg ha −1 plus a control without application. Soil samples were collected after 185 days at the 0.0-20.0 cm layer for laboratorial analysis. Results The composting of chicken manure did not affect soil structural stability. Chicken manure did not alter water-dispersible clay (x = 21.7%), but increased the mean weight diameter of water-stable aggregates (MWD = 5.43 + 0.068 × dose) through the agglomeration of aggregates with 0.5-4 mm into 8-19 mm. Conclusion Even after a short period of 185 days, the application of chicken manure increases the structural stability of Rhodic Ferralsols and its composting, in the way performed by many farmers, is not associated with the improvement of soil structural stability in short-term. However, other advantages arise from the composting of the manure and need to be considered prior its use.