Soil, water and nutrient loss under conventional and organic vegetable production managed in small farms

Agricultural systems with conventional tillage and intensive use of agrochemicals, especially those on high slopes and with shallow soils, have the potential to release pollutants. This study aimed at evaluating the soil, water and nutrient lost via agricultural runoff in large plots (small catchments) under conventional and organic farming of vegetables as well as under forest (control) system in a Cambisol in the Campestre catchment. Samples of runoff were collected biweekly for one year through a Coshocton wheel. The soil and water losses from the conventional farming were 218 and 6 times higher, respectively, than forest. Under organic farming the soil and water losses were 12 and 4 times higher, respectively, than forest. However the soil losses (0.5 to 114 kg ha^(−1) year^(−1)) are considered low in agronomy but environmentally represent a potential source of surface water contamination by runoff associated pollutants. The concentrations and losses of all forms of phosphorus (P) were higher in the conventional system (9.5, 0.9 and 0.3 mg L^(−1) of total P for conventional, organic and forest systems, respectively), while the organic system had the highest concentrations and losses of soluble nitrogen (4.7, 38.6 and 0.4 mg L^(−1) of NO_3-N, respectively). The percentage of bioavailable P was proportionally higher in the organic system (91% of total P lost was as bioavailable P), indicating greater potential for pollution in the short term

Educational procedures guided by emancipatory principles for education on soils in higher education: A proposal

ABSTRACT The traditional paradigm of education, although outdated, still supports Soil Educational procedures in several Brazilian universities. However, the strategic documents of these institutions (Institutional Development Plan-IDP, Institutional Political Project-IPP and Pedagogical Projects of Courses-PPC's) support a critical vision of education, which converges with the emancipatory paradigm and with the purpose of Soil Education (SE), which is the formation and transformation of subjects for conscious actions in reality. To overcome this problem, we propose educational procedures guided by emancipatory principles for two disciplines related to the subject of soils in Higher Education (HE) in a traditional paradigm structure, with the objective of meeting the conception of education supported in the strategic documents of a Brazilian public university and achieving the purpose of SE. A bibliographical research and documental analysis of the strategic documents were carried out to form a theoretical and methodological base. In addition, emancipatory principles were considered in the elements that made up the educational procedures in SE. The proposal was analyzed and discussed based on the behavior of these principles in the structure of the disciplines. To verify how the proposal articulates with the conception of education defended by the university, the analysis started from the didactic-pedagogical aspects expressed in the IDP, IPP, PPC's and Teaching Plans of the disciplines involved in the research. We emphasize that it was possible to propose and apply educational procedures on soils with emancipatory principles within a traditional paradigm structure. Some principles were considered in essence, while others could not be considered or were only partially considered, showing that the traditional paradigm limits principles that go against its foundations. The proposal responded more to the concept of critical education defended in the strategic documents than the Soil Educational procedures with traditional principles elaborated and used by professors, since the proposal considered the student’s protagonism, the constitution of their autonomy, knowledge as relational, research as an educational principle, interculturality and procedural and continuous evaluation. On the other hand, procedures with traditional principles considered students as passive subjects, knowledge was seen as fragmented and their approach was made in an authoritarian way, disregarding students’ knowledge and the evaluation was quantitative. Furthermore, the convergence of educational intentionality between Education in Soils and education with emancipatory principles allows us to state that the emancipatory paradigm was an alternative to achieve the educational and formative purpose in educational processes on soils

CARBON AND PHOSPHORUS BIOGEOCHEMICAL CYCLES IN NATIVE FOREST AND HORTICULTURAL AREAS IN THE METROPOLITAN REGION OF CURITIBA, BRAZIL

This study was carried out to verify if the different phosphate fractions in the soil affect the soil microbial biomass. Soil samples were collected from native forest and horticultural areas, in four municipalities in the Metropolitan Region of Curitiba, Brazil, and evaluated for: carbon (C), nitrogen (N) and phosphorus (P) of microbial biomass (MBC, MBN and MBP, respectively), total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), inorganic phosphorus (iP), organic phosphorus (oP) and available phosphorus (aP. Soil suspensions diluted at 10-4 were spread on plates and phosphate solubilizing bacteria (PSB) were counted. The analyses showed that horticultural areas soils accumulated 43% more TP whereas they lost 23% of TOC and 19% of TN comparing to native areas. 69% of TP in the native areas was organic (oP) whereas 59% of TP in the horticultural areas was inorganic (iP). Horticultural areas had lower numbers of colony forming unities of PSB than native areas.  PSB was positively correlated with the ratio of MBC to TOC (qMic), which in turn, was negatively correlated with TOC and TN. Changes in the soil oP fraction suggested a shift in the soil community bacterial structure and in the values of soil microbial biomass, which may have contributed to lower soil organic matter in the horticultural areas.Este estudo foi conduzido para verificar se as diferentes frações de fosfato do solo afetam a biomassa microbiana do solo Amostras de solo foram coletadas em áreas de floresta nativa e horticultura, em quatro municípios da Região Metropolitana de Curitiba, Brasil, e avaliadas quanto a: carbono (C), nitrogênio (N) e fósforo (P) da biomassa microbiana (MBC , MBN e MBP, respectivamente), carbono orgânico total (TOC), nitrogênio total (TN), fósforo total (TP), fósforo inorgânico (iP), fósforo orgânico (oP) e fósforo disponível (aP), As suspensões de solo diluídas em 10-4 foram espalhadas em placas e as bactérias solubilizadoras de fosfato (PSB) foram contadas. As análises mostraram que os solos das áreas de horticultura acumularam 43% a mais de TP enquanto perderam 23% de TOC e 19% de TN em comparação com as áreas nativas. 69% do TP nas áreas nativas era orgânico (oP) enquanto 59% do TP nas áreas de horticultura era inorgânico (iP). As áreas de horticultura apresentaram menor número de unidades formadoras de colônias de PSB do que as áreas nativas. PSB foi positivamente correlacionado com a razão de MBC para TOC (qMic), que por sua vez, foi negativamente correlacionado com TOC e TN. Mudanças na fração de oP do solo sugeriram uma mudança na estrutura bacteriana da comunidade do solo e nos valores de biomassa microbiana do solo, o que pode ter contribuído para reduzir a material orgânica do solo nas áreas de horticultura

Recomendações para avaliação de populações de minhocas em ecossistemas brasileiros

Earthworms are often related to fertile soils and are also frequently used as environmental quality indicators. However, to optimize their use as bioindicators, earthworm populations must be evaluated together with the environmental and anthropogenic variables regulating their communities. This review sought to identify the earthworm-sampling, soil chemical and physical, and environmental and anthropogenic attributes evaluated in 124 published studies that quantified earthworm abundance (>7,300 samples) in 765 sites with different types of climate, soils, land use, and management systems in Brazil. Soil chemical and physical attributes (except pH) were less reported (≤50% of studies) than other environmental variables such as sampling date, altitude, temperature, precipitation, climate and soil type, and land use (>50% of studies). Earthworms were rarely identified (24%) and few studies (31%) measured their biomass, although most provided adequate information on sampling protocol. Based on their importance in regulating earthworm populations, a set of variables is proposed to be evaluated when studying earthworm communities and other macrofauna groups. This should help guide future studies on earthworms in Brazil and other countries, optimize data collection and replicability, allow comparisons between different studies, and promote the use of earthworms as soil quality bioindicators.As minhocas são frequentemente relacionadas a solos férteis e, também, bastante usadas como indicadores da qualidade ambiental. No entanto, para otimizar seu uso como bioindicadores, as populações de minhocas devem ser avaliadas juntamente com as variáveis ambientais e antropogênicas que regulam as suas comunidades. Esta revisão buscou identificar os atributos relacionados à amostragem de minhocas, físicos e químicos dos solos, e ambientais e antropogênicos avaliados em 124 estudos publicados que quantificaram a abundância de minhocas (>7.300 amostras) em 765 locais com diferentes tipos de clima, solos, uso da terra e sistemas de manejo no Brasil. Os atributos químicos e físicos do solo (exceto pH) foram menos relatados (≤50% dos estudos) do que outras variáveis ambientais, como data de coleta, altitude, temperatura, precipitação, tipo de solo e de clima, e uso do solo (>50% dos estudos). As minhocas foram raramente identificadas (24%) e poucos estudos (31%) mediram sua biomassa, embora a maioria tenha fornecido informações adequadas sobre o protocolo de amostragem. Com base na sua importância para a regulação das populações de minhocas, propõe-se um conjunto de variáveis que devem ser avaliadas no estudo de comunidades de minhocas e outros grupos da macrofauna do solo. Isso deve ajudar a guiar futuros estudos sobre minhocas no Brasil e em outros países, otimizar a coleta e a replicabilidade de dados, permitir comparações entre diferentes estudos e promover o uso de minhocas como bioindicadores da qualidade do solo

A global perspective on soil science education at third educational level; knowledge, practice, skills and challenges

The pivotal role of soil as a resource is not fully appreciated by the general public. Improving education in soil science represents a challenge in a world where soil resources are under serious threat. Today’s high school students, the world’s future landowners, agriculturalists, and decision makers, have the potential to change society’s apathy towards soils issues. This research aimed to compare the level of soil education in high and/or secondary schools in forty-three countries worldwide, together comprising 62% of the world's population. Comparisons were made between soil science content discussed in educationally appropriate textbooks via a newly proposed soil information coefficient (SIC). Interviews with teachers were undertaken to better understand how soil science education is implemented in the classroom. Statistical analyses were investigated using clustering. Results showed that gaps in soil science education were most commonly observed in countries where soil science is a non-compulsory or optional subject. Soil science concepts are predominantly a part of geography or environmental science curricula. Consequently, considerable variability in soil science education systems among investigated countries exists. Soil information coefficient‘s outcomes demonstrated that a methodological approach combining textbooks and the use of modern digitally based strategies in the educational process significantly improved soil education performances. Overall, soil science education is under-represented in schools worldwide. Dynamic new approaches are needed to improve pivotal issues such as: i) promoting collaborations and agreements between high school and universities; ii) encouraging workshops and practical exercises such as field activities; and, iii) implementing technology tools. This, in turn, will prepare the next generation to contribute meaningfully towards solving present and future soil problems

Panorama atual e potencial de aplicação da abordagem dos serviços ecossistêmicos do solo no Brasil

Human pressure on ecosystems has undesirable impacts on human well-being. After the Millennium Project, much interdisciplinary research has been developed worldwide aiming to understand these impacts on ecosystem flows and processes, and to learn about the costs and the benefits of ecosystem services for production. Soil provides many ecosystem services, since its multi-functionality is the basis for food production, water filtration, nutrient cycling, and other goods essential to life. This article presents the main concepts and classifications of soil ecosystem services and of its functions; the indicators and the methods for assessment, modeling, and valuation of ecosystem services; some recent applications to assess and evaluate impacts of agricultural management practices on soil ecosystem services; as well as challenges and opportunities for research and for development of public policies related to agro-environmental sustainability in Brazil. Although the role of soil in supplying ecosystem services is yet undervalued, scientists are gradually recognizing soil processes and functions as fundamental to assess ecosystem services and the effects of land use and management on them. Interdisciplinary approaches to integrate science and public policies are necessary to build governance based on ecosystem services.A pressão humana sobre os serviços ecossistêmicos tem resultado em impactos indesejáveis sobre o bem-estar humano. Com o Projeto Millennium, várias pesquisas interdisciplinares têm sido desenvolvidas em todo o mundo com o objetivo de entender esses impactos sobre os fluxos e os processos dos ecossistemas e internalizar os custos e os benefícios dos serviços ecossistêmicos para a produção. O solo fornece muitos serviços ecossistêmicos, uma vez que sua multifuncionalidade é a base para a produção de alimentos, filtração de água, ciclagem de nutrientes e outros bens essenciais à vida. Este artigo apresenta os principais conceitos e classificações dos serviços ecossistêmicos do solo e de suas funções; os indicadores e os métodos de avaliação, modelagem e valoração dos serviços ecossistêmicos; algumas aplicações recentes para avaliar impactos de práticas de manejo agrícola sobre os serviços ecossistêmicos do solo; bem como os desafios e as oportunidades para a pesquisa e para o desenvolvimento de políticas públicas relacionadas à sustentabilidade agroambiental no Brasil. Apesar de o papel do solo para prestação de serviços ecossistêmicos ainda ser subestimado, os cientistas têm gradualmente reconhecido os processos e as funções do solo como fundamentais para avaliar os serviços ecossistêmicos e os efeitos do uso e manejo da terra sobre eles. Abordagens interdisciplinares que integrem ciência e políticas públicas são necessárias para construir uma governança com base em serviços ecossistêmicos