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Tropical semiarid regions are naturally prone to environmental damage. Human activity can worsen this situation. To understand how human actions affect the ecosystem, plan land use effectively, and establish targeted management practices, assessing environmental vulnerability is crucial. This study focuses on a sub-basin receiving water transfers from the São Francisco River in Brazil's semiarid region. Here, we map and evaluate how land use and occupation alter natural vulnerability. We also propose zoning strategies to support water resource management and implement sustainable development policies in the region. To achieve this, we conducted an integrated analysis of physical factors (soil types, geology, climate, vegetation, and landforms) and spatial land-use data using geographic information systems (GIS) and map algebra techniques. Map algebra allowed us to combine these various datasets within the GIS environment, enabling the creation of maps that synthesize both natural and environmental vulnerability across the study area. Following analysis of these vulnerability maps, our findings reveal a high level of vulnerability. The areas with high to very high degrees of natural vulnerability coincide with the places that have high slopes, high altitudes, Lithic Neosols, and thick vegetation. Furthermore, the interaction between environmental factors and human activity exacerbates vulnerability. Based on the environmental vulnerability assessment, we defined four environmental management zones. These zones require distinct protection measures and management approaches. As a method to potentially improve the basin's vulnerability scenario, soil conservation measures are recommended. This approach is highly relevant for managing land in tropical semiarid regions and, with adaptations to specific regional factors, can be applied globally.

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Human actions can damage the ecosystems and affect the services depending on them, with ample detrimental consequences. In earlier studies, the Conservation Use Potential (PCU) framework proved useful in assessing the capacity for aquifer recharge, suitable land uses and resistance to erosion at the river basin scale. On the other hand, the joint analysis of PCU and land uses allowed identifying the adequacy of current uses in relation to suitability (natural uses) in various basins. This was especially useful from the management perspective in basins with environmental conflicts, where current uses differed from suitability, because the PCU indicated how and where the conflicts should be mitigated. Besides the use as management tool, the PCU has potential to shed light over environmental issues such as ecosystem services, but that was not tempted so far. The aim of this work was therefore to bridge that knowledge gap and frame the PCU's application from the standpoint of Ecosystem Services (ES) assessment. We demonstrated how the PCU could be used to improve provision (recharge), support (sustainable agriculture) and regulation (resistance to erosion) services in a specific basin with land use conflicts (the Upper Rio das Velhas basin, located in Minas Gerais, Brazil), through the planning of suitable uses. It was noted that the studied basin is mostly composed of Very Low, Low and Medium potentials. These classes occur because steep slopes, fragile soils and lithologies with high denudation potential and low nutrient supply dominate in the basin. On the other hand, urban sprawl has a negative impact on all ES, while maintaining agricultural areas with appropriate management can effectively regulate erosion. As per the current results, the premise of using the PCU as joint management-environmental tool was fully accomplished, and is recommended a basis for public policy design and implementation in Brazil and elsewhere.

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BACKGROUND: There are few reports of crop rotations with high residue incorporation in terms of their effects on indicator crop yields and soil properties, so this study evaluated the effect of two medium-term biannual rotations on wheat yield development and soil chemical properties after six years of rotation. METHODS: The experiment was conducted with two biannual rotations (canola-wheat and bean-wheat) and four residue incorporation levels (0%, 50%, 100%, and 200%) in an Andisol in south central Chile. Wheat grain yield and residue production were evaluated during each biannual cycle during three cycles of crop rotation, and soil chemical properties were evaluated at final evaluation. RESULTS: The use of beans as a wheat preculture partially improved grain yield in 7.3%. The chemical properties of the soil showed an increase in pH (0.08 units), organic matter content (15 g kg-1), and concentrations of P (2.8 mg kg-1), S (7.4 mg kg-1), and Al (0.03 cmol+ kg-1) after canola cultivation, while after bean cultivation there was an increase in the available N concentration (3.7 mg kg-1). The use of increasing doses of residue allowed for an increase in the soil pH and decrease in the exchangeable Al concentration. CONCLUSION: The continuous incorporation of the residues produced within the biannual rotations evaluated in this volcanic soil did contribute to improving some chemical properties of the soil without affecting wheat crop yield.

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Mulching use in agriculture has been known since 1802 as the practice of spreading dry leaves and straw on the soil to prevent erosion and water loss. Our study evaluated the mulch effectiveness in the establishment of regenerating seedlings and its contribution to the control of exotic grasses. The studies were carried out in an ecological restoration area in the municipality of Itapira-SP. The treatment with mulching consisted in chemical desiccation with glyphosate herbicide application, keeping the dry grass on the ground. In the control treatment, after chemical weeding, the grass was removed with manual mowing, exposing the soil. Eight months after implantation, we sampled all regenerating seedlings in 100 plots of 50 x 50 cm in each treatment. We considered as seedlings all individuals of tree species less than 100 cm tall. We calculated richness, abundance, similarity, and the relationship of the frequency of seedlings to the height of the mulch. We sampled eight species with 42 seedlings, with only one not identified. The highest abundance and species richness were found in the treatment with mulch (n = 34 individuals; eight species), the most abundant being Schinus terebinthifoliaRaddi (14 individuals) followed by Solanum mauritianumScop. (11 individuals), and Platypodium elegansVog. (three individuals). The presence of exoticgrasses was lower in the plots of the mulching (13%) compared to the control treatment (67%). The highest frequency of seedlings was obtained with mulch height from 21 to 37 cm. We suggest that adaptive management practices, such as the use of the mulching technique, can be implemented in ecological restoration areas, because they favor the natural regeneration of native seedlings and can contribute to the control of exotic grasses, but the height of the layer must be controlled.(AU)

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Since the mid-16th century, the Tietê River has been an important route for the territorial occupation and exploitation of natural resources in the interior of São Paulo and Brazil. Currently, the Tietê River is well known for environmental problems related to water pollution and contamination. However, little attention has been focused on water erosion, which is a serious issue that affects the soils and waters of the hydrographic basin. Thus, this work aimed to estimate soil loss caused by water erosion in this basin, which has an area of approximately 72,000 km², using the Revised Universal Soil Loss Equation (RUSLE). The RUSLE parameter survey and soil loss calculation were performed using geoprocessing techniques. The RUSLE estimated an average soil loss of 8.9 Mg ha-1 yr-1 and revealed that 18% of the basin's territory presents high erosion rates. These are priority zones for conservation practices to reduce water erosion and ensure long-term soil sustainability. The estimated sediment transport was 1.3 Mg ha-1 yr-1, whereas the observed sedimentation, which was calculated based on data from the fluviometric station, was 0.8 Mg ha-1 yr-1. Thus, the results were equivalent considering the large size of the study area and can be used to assist in managing the basin. Estimating soil losses can help in the planning of sustainable management of the Tietê River Hydrographic Basin and highlights the importance of minimizing water erosion, thus helping to prevent additional pollution and contamination with sediments, agrochemicals, and fertilizers.(AU)

Desde meados do século 16, o rio Tietê tem sido uma importante rota de ocupação territorial e exploração dos recursos naturais do interior de São Paulo e do Brasil. Atualmente, o Rio Tietê é bastante conhecido pelos problemas ambientais relacionados à poluição e contaminação das águas. No entanto, pouca atenção tem sido dada à erosão hídrica, que é um problema sério que afeta os solos e as águas da bacia hidrográfica. Assim, este trabalho teve como objetivo estimar as perdas de solo causadas pela erosão hídrica nesta bacia, que tem uma área de aproximadamente 72.000 km², utilizando a Equação Universal de Perdas de Solo Revisada (RUSLE). O levantamento dos parâmetros RUSLE e o cálculo das perdas de solo foram realizados utilizando técnicas de geoprocessamento. O RUSLE estimou uma perda média de solo de 8,9 Mg ha-1 ano-1 e revelou que 18% do território da bacia apresenta altas taxas de erosão. Estas são zonas prioritárias para práticas de conservação para reduzir a erosão hídrica e garantir a sustentabilidade do solo a longo prazo. O transporte de sedimentos estimado foi de 1,3 Mg ha-1 ano-1, enquanto a sedimentação observada, calculada com base nos dados da estação fluviométrica, foi de 0,8 Mg ha-1 ano-1. Assim, os resultados foram equivalentes considerando a grande extensão da área de estudo e podem ser utilizados para auxiliar na gestão da bacia. A estimativa das perdas de solo pode auxiliar no planejamento do manejo sustentável da Bacia Hidrográfica do Rio Tietê e destacar a importância de minimizar a erosão hídrica, auxiliando na prevenção de poluição adicional e contaminação por sedimentos, agroquímicos e fertilizantes.(AU)

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Soil fauna plays a key role in organic matter decomposition. Litter decomposition depends on the relationships of soil fauna and microorganisms as well as climate and litter quality. The decomposer community is sensitive to land use. Thus, physical-chemical disturbances, like soil tillage, can exercise important control on the soil fauna. In order to study the effect of land use and its impact on litter decomposition by soil fauna, a litter-bag experiment was conducted in the Pampa Serrana region, Azul district, Argentina. Litter-bags were made in three different mesh-sizes, allowing the access of micro, micro + meso and micro + meso + macrofauna. Four different treatments were defined: naturalized grassland and three agricultural agroecosystems under different tillage systems, i.e., conservation tillage, conventional-conservation tillage and conventional tillage. Decomposition rate and remaining litter were measured across three different seasons. We found that naturalized grassland obtained the highest decomposition rates and the least remaining litter compared to conservation and conventional tillage systems. No difference in litter decomposition was identified among agricultural agroecosystems. Micro + meso + macrofauna presented the highest decomposition rate and the lowest remaining litter of soil fauna groups, in all agroecosystems. In contrast, microfauna decomposition rate was the lowest and produced the highest remaining litter. Micro + mesofauna presented values of decomposition rate and remaining litter that differed significantly from the rest of the groups in some seasons. These results highlight the importance of soil fauna in litter decomposition and the negative effects of different land use systems on litter decomposition by soil fauna.

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Abstract Water infiltration into soil varies significantly with soil type and management practices. Management practices alter soil physical properties, such as porosity and pore size distribution, which play an important role in infiltration. This study was conducted to assess the effect of the long-term use of two different soil tillage systems (conventional, CT, and no-tillage, NT) on soil structure and water infiltration to understanding of the relationship between physical conditions induced by tillage and water infiltration. The experiments were carried out on a Humic Cambisol in southern Brazil from 1995 to 2016. Soil density, porosity, aggregate diameter and soil water infiltration were evaluated under conventional tillage right after one plowing and two subsequent discings (CT0), and six months after these tillage operations (CT6). The results show that different management systems affect differently soil physical properties and, thus, water infiltration. By mechanical mobilization CT brings about modifications in soil structure which promote an increase in total porosity and mesopority, and a decrease in soil microporosity. This in turn results in an increase in the proportion of larger pores in the plow layer and a decrease in soil density, but also in a decrease in aggregate stability. The CT0 measurements showed the highest infiltration rates which were up to 15 times greater than in the NT treatment. The higher infiltration rate in CT0 wears off with time, but in the CT6 measurements six months after tillage it was still 2 times higher than under NT. Tillage, at least initially, increases total porosity and mesoporosity, while at the same time decreasing microporosity. This results in a larger saturated hydraulic conductivity (K). An increase in total porosity alone does not necessarily increase K, if there is an increase in small pores at the cost of decreasing the number of larger pores.

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ABSTRACT: In the state of Rondônia, deforestation, and inadequate soil use and management have intensified the water erosion process, causing degradation of agricultural land. Modeling is a tool that can assist in the adoption of targeted and effective measures for soil and water conservation in the region. In this context, the objective of the research was to model soil losses due to water erosion in the state of Rondônia using the Revised Universal Soil Loss Equation (RUSLE). The parameters related to rain erosivity, relief, erodibility, and soil cover, as well as the conservation practices of the state of Rondônia, were considered. The modeling steps were performed with the aid of the Geographic Information System. Results were validated with data of total sediments transported with water discharge. The estimated total soil loss was about 605 million tons per year, corresponding to an average loss of 22.50 Mg ha-1 year-1. In 19% of the state, the erosion rate was higher than the soil loss tolerance(T), and these areas should be prioritized for adopting measures to mitigate the erosion process. The RUSLE underestimated the generation of sediments at 0.56 Mg ha-1 year-1, which corresponds to an error of 18.60%. Results obtained can assist in the development of different soil use and management scenarios and provide options for policymakers to encourage soil conservation in the state of Rondônia.

RESUMO: No Estado de Rondônia, o desmatamento, o uso e o manejo inadequado dos solos têm intensificado o processo de erosão hídrica, gerando a degradação de terras agrícolas. Nesse cenário, a modelagem é uma ferramenta que pode auxiliar na adoção de medidas direcionadas e eficazes de conservação do solo e da água na região. Assim, o objetivo do trabalho foi modelar as perdas de solo por erosão hídrica no Estado de Rondônia utilizando a Equação Universal de Perda de Solo Revisada (RUSLE). Foram considerados os parâmetros referentes a erosividade da chuva, relevo, erodibilidade e cobertura do solo e as práticas conservacionistas do Estado de Rondônia. As etapas da modelagem foram realizadas com auxílio de Sistema de Informações Geográficas. Os resultados foram validados com dados de coleta de sedimentos totais transportados com a descarga d'água. A perda de solo total estimada foi cerca de 605 milhões de toneladas ao ano, correspondente a uma perda média de 22,50 Mg ha-1 ano-1. Em 19% do Estado a taxa erosiva foi superior aos limites de tolerância de perda de solo (TPS), sendo que essas áreas devem ser priorizadas para adoção de medidas de mitigação do processo erosivo. A RUSLE subestimou a geração de sedimentos em 0,56 Mg ha-1 ano-1, o que corresponde a um erro de 18,60%. Os resultados obtidos podem contribuir para elaborar distintos cenários de manejo e uso do solo e fornecer alternativas aos formuladores de políticas agrícolas e ambientais, com o intuito de incentivo a conservação do solo no Estado de Rondônia.

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A utilização de plantas de cobertura do solo, no cultivo da videira é uma técnica importante, principalmente para regiões de clima tropical devido às elevadas temperaturas do ar e do solo. Objetivou-se com este trabalho avaliar o desenvolvimento do cultivar de porta-enxerto de videira IAC 572 ‘Jales, consorciadocom diferentes plantas decobertura do solo. O experimento foi conduzido em área experimental da Universidade Estadual do Mato Grosso do Sul -Unidade Universitária de Cassilândia. O delineamento experimental foi em blocos ao acaso, com cinco repetições de duas plantas do porta-enxerto, totalizando dez plantas úteis por tratamento. Os tratamentos foram definidos pelas plantas de cobertura: milheto (Pennisetum glaucum); crotolária (Crotalaria juncea); e mamona (Ricinus communis). Foram avaliadas a altura das plantas, diâmetro de caule, número de ramos e teor relativo de clorofila. O desenvolvimento de porta-enxerto IAC 572 ‘Jales, é favorecido pelo cultivo consorciado com crotalária e milheto na entrelinha de plantio, pois contribui para maior altura de plantas e maior teor relativo de clorofila. A utilização da cultura da mamona, em consórcio com o porta-enxerto, deve ser evitada. Tais resultados demonstram a importância de se conhecer a interação entre e espécie cultivada e as plantas de cobertura do solo. Desta forma, outras espécies devem ser avaliadas, para cultivo em consócio com a cultura da videira em regiões tropicais.(AU)

The use of soil cover crops in the cultivation of the vine is an important technique, especially for tropical climate regions due to high air and soil temperatures. Therefore, this work aimed to evaluate the development of the vine rootstock cultivar “IAC 572 ‘Jales, intercropped with different types of soilcover plants in the Brazilian Cerrado. The experiment was conducted in an experimental area at the State University of Mato Grosso do Sul -Cassilândia University Unit. The experimental design performed on randomized blocks and with five replications of two rootstock plants, totaling ten useful plants per treatment. The treatments were defined by cover crops: millet (Pennisetum glaucum); crotalaria (Crotalaria juncea); and castor (Ricinus communis). Plant height, stem diameter, number of branches and relative chlorophyll content were evaluated. The development of IAC 572 'Jales' rootstock is favored by the intercropping with crotalaria and millet between the planting rows, as it contributes to greater plant height and higher relative chlorophyll content. The use of castor bean culture, in consortium with the rootstock, should be avoided. These results demonstrate the importance of knowing the interaction between the cultivated species and the ground cover crops. Thus, other species must be evaluated, for cultivation in association with the culture of the vine in tropical regions.(AU)

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A utilização de plantas de cobertura do solo, no cultivo da videira é uma técnica importante, principalmente para regiões de clima tropical devido às elevadas temperaturas do ar e do solo. Objetivou-se com este trabalho avaliar o desenvolvimento do cultivar de porta-enxerto de videira IAC 572 ‘Jales’, consorciadocom diferentes plantas decobertura do solo. O experimento foi conduzido em área experimental da Universidade Estadual do Mato Grosso do Sul -Unidade Universitária de Cassilândia. O delineamento experimental foi em blocos ao acaso, com cinco repetições de duas plantas do porta-enxerto, totalizando dez plantas úteis por tratamento. Os tratamentos foram definidos pelas plantas de cobertura: milheto (Pennisetum glaucum); crotolária (Crotalaria juncea); e mamona (Ricinus communis). Foram avaliadas a altura das plantas, diâmetro de caule, número de ramos e teor relativo de clorofila. O desenvolvimento de porta-enxerto IAC 572 ‘Jales’, é favorecido pelo cultivo consorciado com crotalária e milheto na entrelinha de plantio, pois contribui para maior altura de plantas e maior teor relativo de clorofila. A utilização da cultura da mamona, em consórcio com o porta-enxerto, deve ser evitada. Tais resultados demonstram a importância de se conhecer a interação entre e espécie cultivada e as plantas de cobertura do solo. Desta forma, outras espécies devem ser avaliadas, para cultivo em consócio com a cultura da videira em regiões tropicais.

The use of soil cover crops in the cultivation of the vine is an important technique, especially for tropical climate regions due to high air and soil temperatures. Therefore, this work aimed to evaluate the development of the vine rootstock cultivar “IAC 572 ‘Jales’, intercropped with different types of soilcover plants in the Brazilian Cerrado. The experiment was conducted in an experimental area at the State University of Mato Grosso do Sul -Cassilândia University Unit. The experimental design performed on randomized blocks and with five replications of two rootstock plants, totaling ten useful plants per treatment. The treatments were defined by cover crops: millet (Pennisetum glaucum); crotalaria (Crotalaria juncea); and castor (Ricinus communis). Plant height, stem diameter, number of branches and relative chlorophyll content were evaluated. The development of IAC 572 'Jales' rootstock is favored by the intercropping with crotalaria and millet between the planting rows, as it contributes to greater plant height and higher relative chlorophyll content. The use of castor bean culture, in consortium with the rootstock, should be avoided. These results demonstrate the importance of knowing the interaction between the cultivated species and the ground cover crops. Thus, other species must be evaluated, for cultivation in association with the culture of the vine in tropical regions.

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