RESUMO

In the last decades, population growth worldwide boosts agricultural demand for food production. This huge driver rendered global food production more and more specialized, so agricultural landscapes became uniform and monotonic. The loss of diversity is a strong evidence of how modern agricultural landscapes have been disconnecting from nature. Evidence of environmental side-effects from this pathway are abundant in literature. Now, society is pressing towards changing practices aiming for healthy diets and sustainable food production systems. This raises the question: how to reconnect nature and agriculture in the context of future food production? In this review we propose a reconnection process based on the principles of ecological intensification or sustainable intensification. The integrated crop-livestock systems (ICLS) are the most consolidated technological pathway to reconcile crop production with natural processes. These systems are diverse and can partially mimic natural ecosystems exploring the synergies of natural biological processes, while achieving high levels of food production. ICLS promote soil improvements and mitigate greenhouse gas (GHG) emissions, reducing the agricultural share of global warming and climate change. Besides, these systems are more efficient in the use of nutrients and can optimize the use of other inputs such as pesticides. We present evidence of soil health and biogeochemical cycle restoration in addition to system stability improvement, and assume those symptoms as evidence of mixing crops and livestock fostering reconnection with natural processes.(AU)

Assuntos

RESUMO

In the last decades, population growth worldwide boosts agricultural demand for food production. This huge driver rendered global food production more and more specialized, so agricultural landscapes became uniform and monotonic. The loss of diversity is a strong evidence of how modern agricultural landscapes have been disconnecting from nature. Evidence of environmental side-effects from this pathway are abundant in literature. Now, society is pressing towards changing practices aiming for healthy diets and sustainable food production systems. This raises the question: how to reconnect nature and agriculture in the context of future food production? In this review we propose a reconnection process based on the principles of ecological intensification or sustainable intensification. The integrated crop-livestock systems (ICLS) are the most consolidated technological pathway to reconcile crop production with natural processes. These systems are diverse and can partially mimic natural ecosystems exploring the synergies of natural biological processes, while achieving high levels of food production. ICLS promote soil improvements and mitigate greenhouse gas (GHG) emissions, reducing the agricultural share of global warming and climate change. Besides, these systems are more efficient in the use of nutrients and can optimize the use of other inputs such as pesticides. We present evidence of soil health and biogeochemical cycle restoration in addition to system stability improvement, and assume those symptoms as evidence of mixing crops and livestock fostering reconnection with natural processes.

Assuntos

RESUMO

The lowland soils are characterized by high susceptibility to water saturation. This anaerobic condition is usually reported in paddy fields and alters the decomposition process of soil organic compounds. The aim of this study was to evaluate the soil microbial and enzymatic activity of a lowland soil at different soil moisture contents. A poorly drained Albaqualf cultivated with irrigated rice was used to evaluate microbial and enzymatic activity in treatments with different levels of soil moisture, being: i) 60% of field capacity (FC) (60%FC); ii) 100% of FC (100%FC); iii) flooded soil with a 2 cm water layer above soil surface, and iv) soil kept at 60%FC with late flood after 29 days the incubation. The greater soil microbial activity was observed in the 100%FC treatment, being 41% greater than 60%FC treatment and only 2% higher than flooded treatment. The enzymatic activity data by fluorescein diacetate (FDA) hydrolysis corroborated the higher CO2 release in treatments with higher soil moisture content. Differently from the results reported, the main methodologies to evaluate microbial activity still recommend maintenance of the soil with a moisture content close to 60% of the FC. However, in lowland soil with history of frequent paddy fields, the maintenance of moisture close to 60% of the FC can limit the microbial activity. The soil respiration technique can be used to evaluate the microbial activity in flooded soil conditions. However, further studies should be conducted to understand the effect of the cultivation history on the microbial community of these environments.(AU)

Os solos de várzea são caracterizados pela alta suscetibilidade à saturação por água. Esta condição anaeróbica é geralmente encontrada em solos arrozeiros e altera o processo de decomposição dos compostos orgânicos do solo. O objetivo deste estudo foi avaliar a atividade microbiana e enzimática de um solo de várzea sob diferentes teores de umidade no solo. Um Planossolo historicamente cultivado com arroz irrigado foi utilizado para avaliar a atividade microbiana e enzimática em tratamentos com diferentes níveis de umidade do solo, sendo: i) 60% de capacidade de campo (CC) (60%CC); ii) 100% da CC (100%CC); iii) solo inundado com uma camada de água de 2 cm acima da superfície do solo; e iv) solo mantido a 60%CC com inundação após 29 dias da incubação. A maior atividade microbiana do solo foi observada no tratamento 100%CC, sendo 41% maior que o tratamento 60%CC e 2% maior que tratamento inundado. Os dados da atividade enzimática pela hidrólise do diacetato de fluoresceína (FDA) corroboraram a maior liberação de CO2 nos tratamentos com maior umidade do solo. Diferentemente dos resultados encontrados, as principais metodologias para avaliação da atividade microbiana ainda recomendam manter o solo com umidade próxima a 60% da CC. No entanto, em solos de várzea com históricos de cultivos de arroz, a manutenção de umidade próxima a 60% da CC pode limitar a atividade microbiana. A técnica de respiração do solo pode ser usada para avaliar a atividade microbiana em condições de solo inundado. No entanto, mais estudos devem ser realizados para entender o efeito do histórico de cultivo na comunidade microbiana nesses ambientes.(AU)

Assuntos

RESUMO

ABSTRACT: The lowland soils are characterized by high susceptibility to water saturation. This anaerobic condition is usually reported in paddy fields and alters the decomposition process of soil organic compounds. The aim of this study was to evaluate the soil microbial and enzymatic activity of a lowland soil at different soil moisture contents. A poorly drained Albaqualf cultivated with irrigated rice was used to evaluate microbial and enzymatic activity in treatments with different levels of soil moisture, being: i) 60% of field capacity (FC) (60%FC); ii) 100% of FC (100%FC); iii) flooded soil with a 2 cm water layer above soil surface, and iv) soil kept at 60%FC with late flood after 29 days the incubation. The greater soil microbial activity was observed in the 100%FC treatment, being 41% greater than 60%FC treatment and only 2% higher than flooded treatment. The enzymatic activity data by fluorescein diacetate (FDA) hydrolysis corroborated the higher CO2 release in treatments with higher soil moisture content. Differently from the results reported, the main methodologies to evaluate microbial activity still recommend maintenance of the soil with a moisture content close to 60% of the FC. However, in lowland soil with history of frequent paddy fields, the maintenance of moisture close to 60% of the FC can limit the microbial activity. The soil respiration technique can be used to evaluate the microbial activity in flooded soil conditions. However, further studies should be conducted to understand the effect of the cultivation history on the microbial community of these environments.

RESUMO: Os solos de várzea são caracterizados pela alta suscetibilidade à saturação por água. Esta condição anaeróbica é geralmente encontrada em solos arrozeiros e altera o processo de decomposição dos compostos orgânicos do solo. O objetivo deste estudo foi avaliar a atividade microbiana e enzimática de um solo de várzea sob diferentes teores de umidade no solo. Um Planossolo historicamente cultivado com arroz irrigado foi utilizado para avaliar a atividade microbiana e enzimática em tratamentos com diferentes níveis de umidade do solo, sendo: i) 60% de capacidade de campo (CC) (60%CC); ii) 100% da CC (100%CC); iii) solo inundado com uma camada de água de 2 cm acima da superfície do solo; e iv) solo mantido a 60%CC com inundação após 29 dias da incubação. A maior atividade microbiana do solo foi observada no tratamento 100%CC, sendo 41% maior que o tratamento 60%CC e 2% maior que tratamento inundado. Os dados da atividade enzimática pela hidrólise do diacetato de fluoresceína (FDA) corroboraram a maior liberação de CO2 nos tratamentos com maior umidade do solo. Diferentemente dos resultados encontrados, as principais metodologias para avaliação da atividade microbiana ainda recomendam manter o solo com umidade próxima a 60% da CC. No entanto, em solos de várzea com históricos de cultivos de arroz, a manutenção de umidade próxima a 60% da CC pode limitar a atividade microbiana. A técnica de respiração do solo pode ser usada para avaliar a atividade microbiana em condições de solo inundado. No entanto, mais estudos devem ser realizados para entender o efeito do histórico de cultivo na comunidade microbiana nesses ambientes.

RESUMO

This paper aims to discuss the impact of the introduction of pastures and grazing animals in agricultural systems. For the purposes of this manuscript, we focus on within-farm integrated crop-livestock systems (ICLS), typical of Southern Brazil. These ICLS are designed to create and enhance the synergisms and emergent properties have arisen from agricultural areas where livestock activities are integrated with crops. We show that the introduction of the crop component will affect less the preceding condition than the introduction of the livestock component. While the introduction of crops in pastoral systems represents increasing diversity of the plant component, the introduction of animals would represent the entry of new flows and interactions within the system. Thus, given the new complexity levels achieved from the introduction of grazing, the probability of arising emergent properties is theoretically much higher. However, grazing management is vital in determining the success or failure of such initiative. The grazing intensity practiced during the pasture phase would affect the canopy structure and the forage availability to animals. In adequate and moderate grazing intensities, it is possible to affirm that livestock combined with crops (ICLS) has a potential positive impact. As important as the improvements that grazing animals can generate to the soil-plant components, the economic resilience remarkably increases when pasture rotations are introduced compared with purely agriculture systems, particularly in climate-risk situations. Thus, the integration of the pastoral component can enhance the sustainable intensification of food production, but it modifies simple, pure agricultural systems into more complex and knowledge-demanding production systems.(AU)

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