• Rural Digital Europe
• Publications close
• BR close
• Revista Brasileira de Ciência do So... close

ABSTRACT Soil mapping is a permanent demand, but the traditional method does not allow fast execution and low cost. Digital soil mapping (DSM) aims to improve the process by working with models that treat soil spatial variability quantitatively. In this perspective, the objective of the study is to perform DSM of the Parnaíba River Delta, Northeastern Brazil, through the decision tree (DT) integration technique using a set of attributes derived from the digital elevation model (DEM) and satellite images as input parameters. Data matrices were created considering different soil groups. The performance of the J48 machine learning algorithm (DT) was assessed for a set of two data matrices: one elaborated for the mapping units of the pre-existing conventional pedological map and the other for a set of associations determined based on the characteristics of the landscape of the study area with close correlation with the existing soils, mainly due to the source material. From the data processing, digital soil maps were created and validated by means of error matrices, whose reference points were classified in the field and validated using a pre-existing traditional soil map of the area. The results revealed that the attributes derived from satellite images stood out from those derived from DEM in predicting soil groups. Based on the validation coefficients applied (overall accuracy, Kappa index, user’s accuracy and producer’s accuracy), the classification quality was satisfactory, despite the complexity of the environment.

Global agricultural production is expected to double by 2050 due to both global population increase and changes in diets as a consequence of growing incomes. This also means more pressure on water resources, as agriculture accounts for 70 % of global water withdrawal and for energy production as the entire food supply chain accounts for about 30 % of total global energy consumption. Although there are ongoing discussions related to the sustainability of food, water, and energy sectors, integrating these sectors is still rare and challenging. We investigated the effects of agricultural practices on the Food, Water and Energy (F-W-E) nexus security systems by evaluating the results reported in scientific literature. Focusing on the Brazilian Atlantic Forest biome as a study case, our main goals were 1) to elucidate the impacts of rural conservation practices on food, water, and energy production based on literature analysis, 2) to propose F-W-E attributes and evaluate how they are addressed by rural practices. Our findings demonstrated, in general, a positive impact of agricultural conservation practices on F-W-E security attributes. Indeed, 76 % of the combination between a conservational practice with a F-W-E attribute was positive. Some agricultural practices, such as no tillage are very well documented (45 % of all combinations), especially regarding their effects on soil quality parameters. We found few results connecting agricultural practice and energy aspects. These results are key elements that corroborate with the agriculture multifunctionality approach, and the results can better guide the planning of strategies in the agricultural sector and subsidize decision making. Made available in DSpace on 2021-11-26T02:12:59Z (GMT). No. of bitstreams: 1 Interconnections-among-rural-practices-2021.pdf: 746162 bytes, checksum: 70e5288d7ad963d9cd0eb53c03e4b81a (MD5) Previous issue date: 2021

The Cerrado (Brazilian savannah) is a biome of great socio-economic and environmental importance to Brazil. The rapid agricultural expansion in the Cerrado biome areas promoted biogeochemical cycles that affect nitrogen and carbon dynamics, leading to increased greenhouse gas (GHG) emissions. In Brazil, nitrous oxide (N 2 O) is the main gas in agriculture, and agricultural practices increase emissions into the atmosphere. This review aimed to assess the influence of agriculture on N 2 O emissions in the Cerrado region, based on existing data in the literature, and extract patterns of direct N 2 O emissions in different agricultural systems in the Cerrado from existing data. A systematic review of data from 36 scientific publications in the Cerrado region with several crop systems revealed that N 2 O emissions varied from 0.15 kg ha -1 in native cerrado to 4.84 kg ha -1 in conventional tillage. Agricultural systems, nitrogen fertilizer application, and crop residues influence N 2 O emissions. One of the strategies to mitigate emissions is the sustainable intensification of farming systems. Cumulative N 2 O emissions in the Cerrado range from 0.001 to 4.84 kg ha -1 in different land-use scenarios. Soil under the conventional tillage system (CT) had the highest emissions, with an overall average of 1.58 kg ha -1 of N 2 O, compared to no-till system (NT) (0.82 kg ha -1 ) and native Cerrado 0.15 kg ha -1 . Integrated crop-livestock (ICL) systems in the Cerrado had emissions with an overall average of 1.68 kg ha -1 , integrated crop-livestock-forest systems (ICLF) had 1.20 ha -1 , and eucalyptus plantations had 0.48 kg ha -1 .

ABSTRACT Continually rising scarcity in water and nutrient resources, especially in semi-arid agricultural systems, combined with increased frequency of extreme weather events such as drought, contribute to a growing need for resilient and regenerative agricultural ecosystems. However, evaluating a myriad of combinations of producer-led sustainable management practices in on-farm research remains challenging. Few studies have elucidated spatial variability in measured soil properties across the study area due to logistical and economic constraints. As such, this study aimed to: 1) establish soil health assessment and landscape variability data immediately after land-use change to a sustainable pasture management system, and 2) delineate relationships and predictive capability between measured soil health parameters. Soil samples were collected on May 23, 2018 in a grid pattern across two adjacent pastures on a farm in the semi-arid Southern High Plains (Texas, USA) that had recently been converted from long-term continuous cotton production to grazed pasture. Significant differences were found in soil chemical and biological properties between pastures (e.g., ~37 % reduction in microbial community size and 36 and 178 % greater electrical conductivity (EC) and Na contents, respectively, in the East pasture) that likely resulted from recent tillage and receiving irrigation compared to similar soil types and management history in the West pasture. Spatial diagrams of measured parameters revealed localization of measured properties, such as higher clay content and soil organic matter in the southeastern portion of the study area, and clear boundaries between pastures in terms of arbuscular mycorrhizal fungi (AMF) distribution. Soil physical and chemical properties were sufficiently correlated with biological measurements to predict soil microbial community size based on routine soil test analyses. The patterns of distributed elements evaluated in this study can provide a basis for management decisions on soil health and potential contaminant monitoring across the study area. These findings provide insight as to how novel, producer-designed soil health management practices in small semi-arid production systems impact soil properties, as well as help develop cost-effective predictive modeling solutions that aid long-term monitoring efforts. Such strategies will be critical tools in resource-scarce semi-arid regions such as those found in the current study region of Texas, as well as similar semi-arid regions such as northern China and northeastern Brazil. Overall, the results of this study provide direction for long-term soil health monitoring at this site, as well as a critical evaluation of relationships between soil health indicator measurements that aids interpretation and management planning.

Soil acidity is one of the main factors that reduces productivity in agricultural crops, and it is corrected with materials that neutralize acidification. Among soils affected by acidity are those of volcanic origin. At least 30 % of agricultural soils in Chile are of volcanic origin, and acidity correction practices must be constantly performed. This study aimed to evaluate the effectively of two materials that may neutralize soil acidification and increase yield production in Chilean volcanic soils. An experiment was conducted during the 2019-2020 season, in which different acidity correction materials derived from the cellulose industry [Ash + Dregs (AD) and Ash + Dregs + Sludge (ADS)] were applied in three volcanic soils cultivated with wheat in southern Chile (Chillán, Temuco, and Osorno). Treatments were a control, CaCO 3 at an adjusted rate to reach pH 6.0 and AD and ADS at the same rate as CaCO 3 and twice the rate. Results indicated that the application of AD and ADS produced similar effects on pH(H 2 O), Ca 2+ , Mg 2+ , and Al 3+ contents, cationic exchange capacity (CEC), and Al saturation compared with CaCO 3 at the same rate; the effect was directly proportional to the rate used with each AD and ADS. Wheat production at each location was similar for AD, ADS, and CaCO 3 at the same rate; however, it fluctuated between 10.1 and 10.4, 5.4 and 6.5, and 10.0 and 10.3 Mg ha -1 at Chillán, Temuco, and Osorno, respectively. Results indicate that these materials are an alternative to be used as a soil acidity correction amendment.

No-tillage (NT) has been one of the main advances related to soil management in Brazilian agriculture in the last 30 years. However, its full adoption in lowland areas that are traditionally cultivated with flooded rice is still incipient (<5 %). The main reasons are associated with the soil hydromorphic condition and the management of highly recalcitrant residual crop biomass, demanding soil disturbance even occasionally. This review presents a historical survey about the soil management systems utilized in lowland areas in southern Brazil, emphasizing the experiences of NT adoption in areas with flooded rice. Results from studies focused on the main changes in chemical, physical, and microbiological soil properties due to NT adoption were addressed, as well as the NT effects on greenhouse gas emissions and crop yields. Finally, the main challenges and prospects for NT were discussed considering new emerging scenarios for flooded rice production in lowlands, especially soybean rotation and integrated agricultural production systems. No-tillage can increase the soil organic carbon, the cation exchangeable capacity and tends to promote the accumulation of nutrients as nitrogen in surface layers. Improvements in soil aggregation, porosity and water availability are usually observed in NT, but only if medium or long-term trials are considered. NT favors microbial activity in the shallower soil layer by promoting microbial biomass carbon (+45 %), microbial biomass nitrogen (+54 %) and basal respiration (+54 %) compared to conventional tillage (CT), while the activity of extracellular enzymes also may be stimulated. Crop yield tends to be similar among the soil managements systems over time. Seasonal CH4 emissions might be reduced by 21 % with NT adoption without increasing N2O. Plant breeding and geotechnology advances associated with soybean market valuation intensified the introduction of this crop in paddy fields. The main challenge for the full adoption of NT is the need for soil tillage after rice harvesting to correct soil surface irregularities or manage rice straw. In the future, advances in plant breeding and drainage techniques probably will favor the expansion of NT in southern Brazil lowlands. The traditional system of flooded rice cultivation, based on CT and monoculture associated with beef cattle under extensive grazing, is no longer viable and will not be further established. Made available in DSpace on 2022-03-16T07:05:43Z (GMT). No. of bitstreams: 1 Artigo-No-tillage-for-flooded-rice-in-Brazilian.pdf: 1408266 bytes, checksum: 6af083e1a46c74a5b1c3a8ca6021db89 (MD5) Previous issue date: 2021 First online.