Recuperação de áreas severamente degradadas no Cerrado: atributos do solo e respostas das plantas
Carregando...
Data
2021-11-30
Autores
Boni, Thaís Soto
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Diversas são as técnicas utilizadas para recuperação de solos degradados, e quando se trata de áreas onde ocorreu remoção total da vegetação e das camadas superficiais de solo, é necessário utilizar técnicas que contribuam para melhorar as condições edáficas, incorporando matéria orgânica e nutrientes, para que a vegetação e os microrganismos se restabeleçam. O objetivo geral deste trabalho foi avaliar a recuperação de áreas intensamente degradadas, no bioma Cerrado, por meio de indicadores da vegetação como morfofisiologia, status nutricional e levantamento da vegetação estabelecida, em associação com atributos do solo como a fertilidade e atividade microbiológica. O monitoramento do processo de recuperação foi realizado em dois experimentos. Em um deles, foi avaliada a capacidade de aclimatação de duas espécies nativas de Cerrado (Dipteryx alata Vogel e Hymenaea stigonocarpa Mart. ex. Hayne) em 4 tratamentos distintos, uma área de Cerrado preservada (CER) e 3 tratamentos presentes em duas áreas em recuperação há 7 e 15 anos, onde essas espécies foram introduzidas por meio do plantio de mudas. Diferenças fisiológicas (fotossíntese e transpiração) foram verificadas entre os indivíduos do CER e das áreas em recuperação. O estudo da morfologia das folhas mostrou redução da densidade estomática e da espessura foliar nos espécimes nas áreas degradadas em relação à área nativa. Os indivíduos do CER apresentam melhor status nutricional, tendo em vista o comprometimento edáfico das áreas degradadas, mesmo após a realização de intervenções para recuperação. O outro experimento foi estabelecido em campo, em Novembro/2017, utilizando composto orgânico, resíduo ovino, semeadura direta, Stylosanthes spp. e transposição de galharia. Essa área foi avaliada ao longo dos anos para verificar o desempenho das técnicas utilizadas. A incorporação de matéria orgânica foi fundamental para melhorar a condição edáfica da área, tanto química quanto microbiologicamente, o que favoreceu o estabelecimento da vegetação, que foi facilitado pelo mix de sementes nativas introduzidas via semeadura direta, e por espécies de ocorrência espontânea, que em conjunto com a galharia adicionada, reduziram a temperatura e aumentaram a retenção de umidade no solo. A atividade e presença dos microrganismos, atividade das enzimas β-glucosidase, fosfatase ácida, atividade enzimática total e o número de unidades formadoras de colônias de bactérias e fungos, também foram positivamente influenciadas pelo conjunto de ações realizadas, contudo, não foram verificadas diferenças entre a diversidade de bactérias nos tratamentos avaliados. As técnicas e avaliações realizadas no presente estudo são indicadas como ferramentas para recuperar áreas intensamente impactadas e para avaliar os impactos da degradação e das mudanças climáticas globais e, também, são indicadoras do status da recuperação de ambientes degradados.
There are several techniques used to recover degraded soils, and when it comes to areas where there has been total removal of vegetation and surface layers of soil, it is necessary to use techniques that contribute to improving the edaphic conditions, incorporating organic matter and nutrients, so that vegetation and microorganisms can re-establish. The general objective of this work was to evaluate the recovery of intensively degraded areas, in the Cerrado biome, through vegetation indicators such as morphophysiology, nutritional status and survey of established vegetation, in association with soil attributes thus fertility and microbiological activity. The monitoring of the recovery process was carried out in two experiments. In one of them, we evaluated the acclimatization capacity of two native Cerrado species (Dipteryx alata Vogel and Hymenaea stigonocarpa Mart. ex. Hayne) in 4 different treatments, a preserved Cerrado area (CER) and 3 treatments present in two areas in recovery for 7 and 15 years, where these species were introduced by planting seedlings. Physiological differences (photosynthesis and transpiration) were verified between individuals from the CER and from the recovering areas. The study of leaf morphology showed a reduction in stomatal density and leaf thickness in specimens in degraded areas compared to the native area. Individuals from the CER have better nutritional status considering the edaphic impairment of degraded areas, even after carrying out interventions for recovery. The other experiment was established in the field in November/2017, using organic compost, sheep residues, direct seeding, Stylosanthes spp. and brushwood transposition. This area has been evaluated over the years to verify the performance of the techniques used. The incorporation of organic matter was fundamental to improve the edaphic condition of the area, both chemically and microbiologically, which favored the establishment of vegetation, which was facilitated by the mix of native seeds introduced via direct seeding, and by spontaneously occurrence species, which in together with the added brushwood, they reduced the temperature and increased the soil moisture retention. The activity and presence of microorganisms, activity of β-glucosidase and acid phosphatase enzymes, total enzymatic activity and number of bacterial and fungal colony forming units were also positively influenced by the set of actions performed, however, there were no differences between the diversity of bacteria in the evaluated treatments. The techniques and assessments carried out in this study are indicated as tools to recover heavily impacted areas and to assess the impacts of degradation and global climate change, and are also indicators of the status of recovery of degraded environments.
There are several techniques used to recover degraded soils, and when it comes to areas where there has been total removal of vegetation and surface layers of soil, it is necessary to use techniques that contribute to improving the edaphic conditions, incorporating organic matter and nutrients, so that vegetation and microorganisms can re-establish. The general objective of this work was to evaluate the recovery of intensively degraded areas, in the Cerrado biome, through vegetation indicators such as morphophysiology, nutritional status and survey of established vegetation, in association with soil attributes thus fertility and microbiological activity. The monitoring of the recovery process was carried out in two experiments. In one of them, we evaluated the acclimatization capacity of two native Cerrado species (Dipteryx alata Vogel and Hymenaea stigonocarpa Mart. ex. Hayne) in 4 different treatments, a preserved Cerrado area (CER) and 3 treatments present in two areas in recovery for 7 and 15 years, where these species were introduced by planting seedlings. Physiological differences (photosynthesis and transpiration) were verified between individuals from the CER and from the recovering areas. The study of leaf morphology showed a reduction in stomatal density and leaf thickness in specimens in degraded areas compared to the native area. Individuals from the CER have better nutritional status considering the edaphic impairment of degraded areas, even after carrying out interventions for recovery. The other experiment was established in the field in November/2017, using organic compost, sheep residues, direct seeding, Stylosanthes spp. and brushwood transposition. This area has been evaluated over the years to verify the performance of the techniques used. The incorporation of organic matter was fundamental to improve the edaphic condition of the area, both chemically and microbiologically, which favored the establishment of vegetation, which was facilitated by the mix of native seeds introduced via direct seeding, and by spontaneously occurrence species, which in together with the added brushwood, they reduced the temperature and increased the soil moisture retention. The activity and presence of microorganisms, activity of β-glucosidase and acid phosphatase enzymes, total enzymatic activity and number of bacterial and fungal colony forming units were also positively influenced by the set of actions performed, however, there were no differences between the diversity of bacteria in the evaluated treatments. The techniques and assessments carried out in this study are indicated as tools to recover heavily impacted areas and to assess the impacts of degradation and global climate change, and are also indicators of the status of recovery of degraded environments.
Descrição
Palavras-chave
Subsolo exposto, Resíduos, Semeadura direta, Ecofisiologia, Atividade enzimática, Diversidade bacteriana, Exposed subsoil, Residues, Direct seeding, Ecophysiology, Enzymatic activity, Bacterial diversity