Crop-Livestock Integration Improves Physical Soil, Agronomic and Environmental Aspects in Soybean Cultivation.

Soybean is one of the most widely grown crops in the world and technologies are increasingly needed to increase productivity without impacting environmental degradation. In this context, the aim was to evaluate the action of forage plants of the genus Brachiaria sp. in crop-livestock integration on physical soil, agronomic and environmental aspects of soybean cultivation. The experiment was conducted in a subdivided plot design with seven integrated systems corresponding to the previous cultivation of Paiaguas palisadegrass, Xaraes palisadegrass and Ruziziensis grass in monocropping and intercropped with maize, as well as maize in monocropping. In the subplots, two grass management systems were evaluated: free growth and a grazing simulation cut. The bulk density and least limiting water range were assessed using soil samples and, after the pastures were desiccated when the soybean crop was planted, straw decomposition and plantability. A soil physics diagnosis by the bulk density and least limiting water range showed that the Paiaguas palisadegrass and Xaraes palisadegrass improved the soil environment due to biological soil loosening. The remaining mulch biomass did not affect soybean sowing and the adoption of Brachiaria sp. grass in the off-season, in addition to contributing to the provision of environmental services, and did not compromise grain productivity in succession.

Interactions between land use and soil type drive soil functions, highlighting water recharge potential, in the Cantareira System, Southeast of Brazil.

Most of the soil quality assessment protocols are focused on crop production and conservation management, while studies on vital soil functions, such as water recharge potential, should be incorporated into the monitoring of impacts on environmental quality. Our objective was to evaluate, through the Nexus approach, how dynamic (land use and management) and inherent (soil type) factors impact soil physical properties and processes that drive water recharge potential, biomass production, and water erosion in the Cantareira System, Brazil. The assessment considered three soils (Typic Hapludult, Typic Dystrudept, and Typic Usthortent) and four land uses (native forest, rotational grazing, extensive grazing, and eucalyptus), which constitute the main soils and land uses in the Cantareira System region. Representative soil samples were collected at 0-5 and 30-35 cm depth and analyzed for several soil physical quality indicators, which were used to calculate a Soil Physical Quality Index based on soil functions. Converting the native forest to eucalyptus and pasture reduced the overall soil physical quality and water recharge potential. The groundwater recharge potential function in the topsoil has the highest score of 0.72 for Typic Dystrudept in native forest contrasting with 0.16 for extensive pasture. Typic Dystrudept obtained the highest value of the SPQI value (0-5 cm: 0.85; 30-35 cm: 0.90) for native forests when compared to Typic Hapludult (0-5 cm: 0.76; 30-35 cm: 0.57) and Typic Usthortent (0-5 cm: 0.75; 30-35 cm: 0.72). Our findings sustain that land use effects on soil functions depends on soil type. Inclusion of soil type into the Nexus approach increases the understanding of natural resources and derived benefits of water, energy and food in the Cantareira System.

Deep Tillage Strategies in Perennial Crop Installation: Structural Changes in Contrasting Soil Classes.

Tillage modifies soil structure, which can be demonstrated by changes in the soil's physical properties, such as penetration resistance (PR) and soil electrical resistivity (ρ). The aim of this study was to evaluate the effect of deep tillage strategies on three morphogenetically contrasting soil classes in the establishment of perennial crops regarding geophysical and physical-hydric properties. The experiment was conducted in the state of Minas Gerais, southeastern Brazil. The tillage practices were evaluated in Typic Dystrustept, Rhodic Hapludult, and Rhodic Hapludox soil classes, and are described as follows: MT­plant hole; CT­furrow; SB­subsoiler; DT­rotary hoe tiller; and DT + calcium (Ca) (additional liming). Analyses of PR and electrical resistivity tomography (ERT) were performed during the growing season and measurements were measured in plant rows of each experimental plot. Undisturbed soil samples were collected for analysis of soil bulk density (Bd) at three soil depths (0−0.20, 0.20−0.40, and 0.40−0.60 m) with morphological evaluation of soil structure (VESS). Tukey's test (p < 0.05) for Bd and VESS and Pearson linear correlation analysis between Bd, ρ, and PR were performed. Soil class and its intrinsic attributes have an influence on the effect of tillage. The greatest effect on soil structure occurred in the treatments DT and DT + Ca that mixed the soil to a depth of 0.60 m. The ρ showed a positive correlation with Bd and with PR, highlighting that ERT may detect changes caused by cultivation practices, although ERT lacks the accuracy of PR. The soil response to different tillage systems and their effects on soil structure were found to be dependent on the soil class.

Endophytic Fungi Assures Tropical Forage Grass Growth by Water Stress Tolerances.

Forage plants is the base of beef and dairy cattle production. While water stress limits agricultural production worldwide, endophytic fungi can play a beneficial role for plants, such as tolerance to biotic and abiotic stresses. The objective of this work was to evaluate the effect of inoculation of the endophytic fungi Paraconiothyrium estuarinum (CML 3695, CML 3696, CML 3699) and Paraconiothyrium cyclothyrioides (CML 3697, CML 3698) on agronomic characteristics of two forage species, Brachiaria brizantha (A. Rich) Stapf. cv. Marandu and Megathyrsus maximus Jacq. cv. BRS Mombaça, under different available water capacities. The treatments simulated a long drought period (LDH) equivalent to 10% of the available water capacity (AWC) and simulated 7 (7 DH) and 14 days of drought (14 DH) without water supply. The grasses were evaluated for length and dry weight of shoots and roots. All treatments reached humidity below the permanent wilting point (PWP) and the highest variation in soil moisture was observed at 14 DH, for both grass species. The endophytic fungi promoted an average 15% increase in shoot length (SL) for B. brizantha and an increase of 34% for SL, 266% for Dry Shoot Mass (SDM), and 340% for Dry Root Mass (RDM) for M. maximus treated with P. estuarinum (CML 3699) at 7 DH. Paraconiothyrium estuarinum (CML 3699) guaranteed the highest tolerance to water deficit and sustainable growth performance to both tested grasses.

Occasional tillage in no-tillage systems: A global meta-analysis.

No-tillage (NT) is a major component of conservation agricultural systems. Challenges that have arisen with the adoption of NT include soil compaction, weed management, and stratification of organic matter and nutrients. As an attempt to overcome these challenges, occasional tillage (OT) has been used as a soil management practice in NT systems. However, little is known about the impacts of OT on agronomic and environmental factors. For this reason, the objectives of this meta-analysis were: 1) to summarize the effects of OT on crop productivity, soil physical, chemical and biological properties, soil erosion and weed control; 2) to discuss the main aspects of NT management to optimize the use of OT; 3) to point out shortcomings in the diagnosis of soil compaction in NT systems, which may lead to erroneous decision-making processes regarding the use of OT. Overall, OT did not affect crops yields, although increased crop yields were observed in regions under water restriction and in soils with low retention capacity and water availability; OT improved soil physical properties (penetration resistance, soil bulk density, macroporosity, and total porosity), with persistence, generally, greater than 24 months, and decreased the soil aggregates stability; total organic carbon was reduced, particularly when plow/harrow was used and NT was already consolidated, and there was no effect on pH and available P; OT increased microbial biomass carbon, but had no effect on total microbial activity; soil erosion was reduced due to increased soil-water infiltration and reduced runoff, and finally, weed management was also improved by OT. It is suggested that suitable NT implementation and management, with the correct application of NT principles, will overcome problems associated with NT. As soil compaction is the main justification for the use of OT, methods of diagnosis and monitoring of soil compaction should be improved to assist in decision-making.

Assessing pedotransfer functions to estimate the soil water retention / Validação de funções de pedotransferência para estimativa da retenção de água no solo

Considering the importance of soil water retention for agricultural and environmental purposes, the objective of this study was to assess three pedotransfer functions (PTFs) used to estimate the soil moisture at field capacity (FC) based on soil attributes easily determined. A collection of 17 soils from the Cerrado and Pantanal biomes, including surface and subsurface horizons, was used. PTF-1 considers clay, organic matter, coarse sand, and microporosity; PTF-2 clay, total sand, and organic matter; and PTF-3 only microporosity. The estimated FC values were correlated to soil moisture values measured at different soil water potentials (0, 6, 10, 33, 100, 300, and 1500 kPa) to verify which potential corresponded to estimated FC. The data were subjected to regression analysis and Mann-Whitney rank-sum test to compare predicted and measured values and to principal component analysis (PCA). The analysis of the full dataset indicated that there was a strong correlation (R 0.84­0.91; R2 0.71­0.82; RMSE 0.07­0.09) between estimated FC and soil water retention measured at potentials of 10 kPa and 33 kPa. FC estimated by PTF-3 correlated better with water holding capacity at 6 kPa. When the PTFs were reapplied to homogeneous soil groups (identified by PCA analysis), the correlation between predicted and measured FC was decreased.

Considerando a importância da retenção de água no solo para fins agronômicos e ambientais, objetivou-se com este trabalho avaliar três funções de pedotransferência (FP) para estimativa da capacidade de campo (CC) com base em atributos de solo facilmente determinados. Uma coleção de 17 solos dos biomas Cerrado e Pantanal, incluindo amostras superficiais e subsuperficiais, foram utilizadas. FP 1 considera o conteúdo de argila, matéria orgânica, areia grossa e microporosidade. FP 2 considera argila, areia total e matéria orgânica. A FP 3 leva em consideração apenas microporosidade. Os valores estimados de CC foram correlacionados aos valores de umidade obtidos em diferentes potenciais (0, 6, 10, 33, 100, 300, and 1500 kPa) com o intuito de verificar qual potencial corresponde à CC estimada. Os dados foram submetidos à análise de regressão, ao teste Mann-Whitney rank-sum para comparar valores medidos e estimados e realizada análise de componentes principais (PCA). Considerando todo o conjunto de dados, foi obtida uma forte correlação (R 0.84­0.91; R2 0.71­0.82; RMSE 0.07­0.09) entre CC estimada e a umidade do solo obtida nos potenciais de 10 kPa e 33 kPa. A CC estimada pela FP 3 correlacionou melhor com a retenção de água no potencial de 6 kPa. Quando as FP's foram reaplicadas em grupos de solos homogêneos (identificados pela PCA), a correlação entre valores estimados e medidos diminuiu.

Índice s no diagnóstico da qualidade estrutural de latossolo muito argiloso sob manejo intensivo / S index in structural quality diagnostic of a very clayey oxisol under intense management

Neste estudo foi verificada a adequação de uso do índice S no diagnóstico da qualidade estrutural de um Latossolo Vermelho distrófico de cerrado cultivado com cafeeiro sob sistema de manejo que adota a aplicação de altas doses de gesso na linha da cultura, cultivo e manejo mecanizado de braquiária na entrelinha da cultura, além de preparo do sulco de plantio até 60 cm de profundidade, dentre outras técnicas de manejo intensivo. O índice S foi correlacionado à densidade e à porosidade do solo nas profundidades de 5, 20, 40 e 80 cm, na linha do cafeeiro, e 5, 10, 20, 40, 65 cm na entrelinha do cafeeiro. Para a determinação do índice S nas diferentes profundidades e locais de amostragem foram construídas curvas de retenção de água, sendo utilizadas amostras com estrutura preservada. Os valores deste atributo físico foram superiores a 0,045 indicando ótima qualidade física do solo sob o sistema de manejo adotado. Houve boa correlação entre o índice S com os atributos físicos analisados, mostrando ser esta uma boa ferramenta a ser utilizada no diagnóstico da qualidade estrutural do solo.

In this study we verified the adequacy of use of the Dexter S index in the diagnosis of structural quality of a Cerrado Oxisol cultivated with coffee in management system that adopts the application of high doses of gypsum in row culture, mechanized cultivation and management of Brachiaria in the interrows, and preparation of the furrow 60 cm deep, among other techniques of intensive management. The S was correlated with the density and porosity of the soil at depths of 5, 20, 40 and 80 cm along the row of coffee, and 5, 10, 20, 40, 65 cm between rows of coffee. For the determination of the S at different depths and sampling sites were built water retention curves, using samples with structure preserved. The values of this physical attribute were greater than 0.045 indicating good soil physical quality under the management system adopted. There was good correlation between the S with the physical attributes analyzed, showing that this is a good tool to use in the diagnosis of structural soil quality.