Telmo Jorge Carneiro Amado

Management systems, within the context of regenerative agriculture, have been identified as strategies to improve soil health and reduce the use of external inputs. These management systems that use conservationist practices seek to minimize yield losses due to climatic events such as droughts, but the effect of these practices on weed control is poorly documented. The main objective of the research was to evaluate the comparative effect between management systems with cover crops on weed density and soybean yield. This study was developed in the southern region of Brazil in a subtropical climate. The treatments in this study consisted of: conventional system using black oats as a cover crop, no-tillage system using black oats, and no-tillage system with a polyculture of cover crops. The results showed that no-tillage with the use of forage radish followed by a second sowing with several species of cover crops (polyculture) was efficient in minimizing the density and height of Conyza bonariensis and Solanum americanum. The suppression of these two weed species was associated with the greater production of dry matter from these cover crops and, consequently, resulted in a greater grain yield of soybeans grown in succession.

Phosphorus (P) is an important element, essential for plant growth and development. In this context, the use of microorganisms as promoters of P availability in the soil solution is necessary. This study defined management zones (MZ) based on the spatial variability of soil P content and evaluated the effects of P application, both from mineral and biological sources, within each MZ on soybean performance and soil properties after application. The results indicated that P management, especially in MZ with lower initial P content, is effective in increasing soybean yield (11.57%) and P content in soil (19%). The supply of P via solubilizer increased the thousand-grain weight by up to 5.84% and the soybean yield by up to 5.38%. Increases of up to 4.79% in the thousand-grain weight, 5.55% in grain P content and up to 6.29% in soybean yield, were observed for the supply of P via mineral source. The use of MZ based on the spatial variability of P content in the soil proved to be an efficient tool for optimizing P application, contributing to greater yield and better use of resources, especially in areas with low fertility. This reinforces the importance of precision management strategies in the use of P fertilizers, adapted to specific soil conditions, to maximize yield and improve nutrient use efficiency.

A obtenção dos níveis de nutrientes nas plantas é essencial no manejo nutricional de florestas plantadas. Este estudo avaliou a relação entre comportamento espectral, capturado por sensor hiperespectral, e o estado nutricional de mudas clonais de Eucalyptus saligna submetidas a diferentes níveis de adubação nos primeiros 90 dias pós-plantio. Foram plantadas 150 mudas em delineamento em blocos casualizados, com três tratamentos: sem adubação (T0), 20% (T1) e 50% (T2) das doses recomendadas de Nitrogênio (N), fósforo (P) e potássio (K). A reflectância foliar foi medida com espectroradiômetro FieldSpec® 3, e realizada análise química dos nutrientes. Dados espectrais foram organizados em subconjuntos multiespectral e índices de vegetação (IVs). As variáveis biofísicas e espectrais foram submetidas à ANOVA, Tukey, Kruskal-Wallis e Dunn. Análise de Componentes Principais e correlação de Spearman foram aplicadas. A regressão linear avaliou relações entre IVs/bandas e conteúdos nutricionais. Os resultados mostraram diferenças significativas entre tratamentos, com maiores conteúdos totais de N, P, K e proteínas em T2. Teores de P, K e proteína foliar foram superiores em T2. IVs como GNDVI, NDRE e CCCI discriminaram T2. As análises confirmaram forte relação entre espectro e nutrientes, destacando a espectrorradiometria como ferramenta eficaz para diagnóstico nutricional em campo.

The authors have recognized several errors in the original publication

Accurate and low-cost tree inventories in forest plantations are essential for an effective production management. Stimulated by recent advancements in Unmanned Aerial Vehicle (UAV) imagery coupled with artificial intelligence, and by the interest in developing models capable of supporting decision-making on silvicultural and forest management, this study aimed to evaluate the performance of different vegetation indices in detecting Eucaliptus saligna individuals by using an improved deep learning model. The tree-individual detection model was created using the YOLOv8n algorithm using UAV RGB images and vegetation indices (VI) generated from the multispectral sensor onboard the UAV. Nine VIs were selected for training (65%) and testing (35%) the models. The proposed framework demonstrated that the MPRI, PSRI, and NDVI indices achieved an F1 score of 0.98 and a precision of 0.97 for detecting E. saligna individual trees six months after planting. Our study demonstrates the robustness of the proposed framework and recommends the application of the MPRI index in individual tree detection due to its efficient performance, cost-effectiveness, and simplicity, as it only utilizes regions of the visible spectrum.

Frequent and intensive tillage in conventional agriculture disrupts soil aggregates, engendering significant depletion of soil organic carbon (SOC) stocks. Long‐term studies are essential for assessing the impact of sustainable practices on aggregate dynamics and carbon sequestration in sugarcane monocropping in tropical ecosystems. The following hypothesis was first, conventional sugarcane management would degrade soil, thereby reducing C stocks and breaking down aggregates. Second, conservation management that involves reduced disturbance could restore C storage, reaching levels similar to those observed in native vegetation (NV) over time. Third, macroaggregation could be a key mechanism for C storage under conservation management. This study evaluated the distribution of SOC among distinct aggregate classes under conventional (CC) and minimum (MC) cultivation in a 60‐year‐old sugarcane system, comparing results with undisturbed NV. The monitored properties included aggregate mass, SOC content and stock, weighted average diameter (WAD), aggregate and C stability indexes (ASI and CSI), soil C–CO₂ emissions, and C preservation capacity (CPC). The long‐term CC had a significant impact on aggregate dynamics, manifesting in a reduction in macroaggregate mass and SOC content, an increase in CO₂ emissions, and a decrease in CPC. While the total SOC stock remained comparable in NV and MC (76 Mg C ha⁻¹), CC led to a 20% SOC loss. Although CC led to an increase in microaggregate C, it failed to counterbalance the loss of macroaggregate C. The ASI, with a reliability of approximately 99% in NV, exhibited a decline of 1% at 10 cm and 2% at 20 cm under MC and CC conditions. Concurrently, WAD reduced by 16% at 10 cm. CSI exhibited higher levels in NV and MC compared to CC at 10 cm depth. CPC in large macroaggregates was highest in NV (21 g kg⁻¹), decreasing by 50% in CC (7 g kg⁻¹) and by 33% in MC (14 g kg⁻¹). At a depth of 20 cm, large macroaggregate mass was 28% lower in CC and 14% lower in MC compared to NV, resulting in a 29% and 21% reduction in macroaggregate C stock, respectively. In summary, the application of MC resulted in the preservation of SOC stocks at levels comparable to those observed in NV, thereby underscoring its capacity to maintain crop sustainability and augment carbon sequestration in tropical sugarcane systems.

The main hypothesis of this study is that a conservationist system combined with soil regenerative practices can reduce the incidence of Macrophomina phaseolina in soybean crops and consequently increase productivity. The study wasconducted in the experimental area of the Federal University of Santa Maria, Frederico Westphalen Campus, RS, Brazil, during the 2023/2024 harvest. The experimental design consisted of main blocks in which three production systems were allocated: 1) notillage black oats system with physical intervention; 2) no-tillage black oats system; and 3) no-tillage polyculture system. The results showed that the no-tillage polyculture system presented 36.5% and 31.7% lower incidence of Macrophomina phaseolina and consequently higher grain productivity with an increase of 23% (675 kg ha-1) and 15.08% (473 kg ha-1) in relation to the notillage black oats system with physical intervention and no-tillage black oats system. The weight of a thousand grains was thevariable which best explained the increase in productivity, with a significant increase of 7.9% and 7.01% in the no-tillage polyculture system compared to the no-tillage black oat system with physical intervention and no-tillage black oat system. The notillage system combined with regenerative practices is the best way to minimize losses due to root diseases in soybean crops. A hipótese principal desta pesquisa é que, sistema conservacionista aliado a práticas regenerativas de solo possa reduzir a incidência de Macrophomina phaseolina na cultura da soja, e consequentemente aumentar a produtividade. O estudo foi conduzido na área experimental da Universidade Federal de Santa Maria, Campus Frederico Westphalen - RS, durante a safra 2023/2024. O delineamento experimental foi constituído por blocos principais, onde foram alocados três sistemas de produção: 1) sistema convencional aveia preta, 2) sistema plantio direto aveia preta e 3) sistema plantio direto policultivo. Os resultados demonstram que o sistema plantio direto policultivo apresentou 36,5% e 31,7% menor incidência de Macrophomina phaseolina e consequentemente maior produtividade de grãos com aumento de 23% (675 kg ha-1) e 15,08% (473 kg ha-1) em relação ao sistema convencional aveia preta e sistema plantio direto aveia preta. O peso de mil grãos foi a variável que melhor explicou o incremento de produtividade, com aumento significativo de 7,9% e 7,01% no sistema plantio direto policultivo em comparação ao convencional e plantio direto aveia preta. O sistema plantio direto aliado a práticas regenerativas é o caminho para minimizar as percas por doenças radiculares na cultura da soja.

The objective of this work was to evaluate the effect of different sowing times and cultivars on the expression of yield components of soybean grown in contrasting environments. Three experiments were carried out in two environments. In Condor, RS, Brazil, experiments were established in the 2018/2019 and 2022/2023 growing seasons, at two sowing times: November 8 and 25, in 2018/2019; and November 5 and 25, in 2022/2023. The evaluated cultivars were 53I54RSF IPRO, 6563RSF IPRO, and 5958RSF IPRO. In São Borja, RS, Brazil, the 2022/2023 experiment included the cultivars 57I52RSF IPRO, 55I57RSF IPRO, 6101XTD, O590 I2X, 5995I2X, and 64I61RSF IPRO. Variables were grouped as follows: plant stature (plant height, and first pod insertion height); plant architecture (fertile nodes and branches); pod distribution by grain number (on main stem and branches); grain yield; and thousand-grain weight. Data were subjected to the analysis of variance and to the Tukey’s test at 5% significance. In Condor, the sowing in the first half of November was more favorable under good weather (2018/2019), while the sowing in the second half of that month was better under adverse conditions (2022/2023). In São Borja, the 6101XTD cultivar showed the highest grain yield in 2022/2023, standing out under extreme drought conditions.

This study aimed to investigate different production environments, through diagnosis of the chemical, physical attributes and enzymatic activity of the soil, in addition to evaluating strategies to improve the quality of these environments and their impact on the productivity of commercial crops. Low productivity environments were characterized by lower dry matter production of cover crops with a reduction of up to 46.2%, greater resistance to soil penetration at a depth of 40-60 cm, lower levels of soil organic matter in the uppermost layer superficial and also in depth, combined with lower enzyme activity. It was possible to restore productivity in the low corn crop environment, by up to 15.34% in the vegetative treatment + organic conditioner + biological input and 5.11% for vegetative + biological input. There was a positive synergism as a residual effect for both environments in the off-season soybean crop in the vegetative treatment + organic conditioner + biological input, up to 39.53% in the low environment and 25% for the high environment. For wheat cultivation, it was possible to increase productivity in the low environment by up to 1.92% in the vegetative method, 9.09% vegetative + organic conditioner and 24.4% vegetative + biological input in relation to the high environment. Neste estudo objetivou-se investigar diferentes ambientes de produção, através de diagnóstico dos atributos químicos, físicos e atividade enzimática do solo, além de avaliar estratégias para melhorar a qualidade destes ambientes e seu reflexo na produtividade de culturas comerciais. Os ambientes de baixa produtividade foram caracterizados pela menor produção de matéria seca das plantas de cobertura com redução de até 46,2%, maior resistência a penetração do solo na profundidade de 40-60 cm, menores teores de matéria orgânica do solo na camada mais superficial e também em profundidade, aliado a menor atividade das enzimática. Foi possível restaurar a produtividade no ambiente de baixa na cultura do milho, em até 15,34% no tratamento vegetativo + condicionador orgânico + insumo biológico e 5,11% para vegetativo + insumo biológico. Houve um sinergismo positivo como efeito residual para os dois ambientes na cultura da soja safrinha no tratamento vegetativo + condicionador orgânico + insumo biológico em até 39,53% no ambiente de baixa e 25% para o ambiente de alta. Para a cultura do trigo, foi possível aumentar a produtividade no ambiente de baixa em até 1,92% no método vegetativo, 9,09% vegetativo + condicionador orgânico e 24,4% vegetativo + insumo biológico em relação ao ambiente de alta.