RESUMO
Zein has gained popularity over the past few years as an incredible food and bio-based materials. The potential functions and health benefits of zein microcapsules or micro-/nanoparticles in bioactive components delivery, structured emulsion, etc., have received great attention. However, the development has been limited by colloidal destabilization, especially when thermal processing is involved. There is a recent trend in developing zein-polysaccharide complexes (ZPCs), which has tremendously improved the performance of zein-based colloidal carrier systems or emulsions. Increasing our understanding of zein interactions and their contribution to the structure of various macromolecules can help us to develop novel biomaterials that can be used in food, agriculture, biomedicine, and cosmetics. In addition, these nanocarriers are suitable for the encapsulation and delivery of bioactive compounds which have positive perspective in food industry. Therefore, this article aimed to review recent advances in the ZPCs that can be applied to functional or health-promoting foods, with a focus on the characteristics of different ZPCs, factors and mechanisms affecting the stability (especially thermal stability) of these complexes, and their application in food industry as a carrier for BCs. Further, the stability of ZPCs based emulsions under processing and physiological environments, as well some typical effective methods are introduced. Also, the principal challenges and prospects were enumerated and discussed.
Assuntos
Zeína , Agricultura , Materiais Biocompatíveis , Emulsões , Polissacarídeos , NanotecnologiaRESUMO
The material content and nutritional composition of tea vary during different picking periods, leading to variations in tea quality. The absence of rapid evaluation methods for identifying tea quality at different picking periods hinders the smooth operation and maintenance of agricultural production and market sales. In this work, hyperspectral technology combined with the multibranch kernel attention network (MBKA-Net) is proposed to identify the overall quality of tea during different picking periods. First, spectral information of six different tea picking periods is obtained using a hyperspectral system. Second, the multibranch kernel attention (MBKA) method is proposed, which effectively mines spectral features through multiscale adaptive extraction and achieves classification of tea at different picking periods. Finally, MBKA-Net achieves outstanding performance with 96.18% accuracy, 97.14% precision, and 97.18% recall. In conclusion, MBKA-Net combined with a hyperspectral system provides an effective detection method for identifying the quality of tea at different picking periods.
Assuntos
Agricultura , CháRESUMO
Earthworms are among the most important animals (invertebrates) for soil health. Many chemical substances released into nature for agricultural development, such as pesticides, may have unwanted effects on those organisms. However, it is essential to understand the extent of the impact of chemicals on soil health first and then make the proper decisions for regulatory or commercial purposes. We hypothesize that there is an expressible quantitative structure-activity relationship (QSAR) between the structure of pesticide compounds and the acute toxicity effect of earthworm species Eisenia fetida. The description of this relationship allows for a better assessment of the impact of chemicals on the said earthworm. To describe this relationship, a dataset of chemicals was collected from open-access sources to develop a mathematical model. A novel approach, combining genetic algorithm and Bayesian optimization, was used to select structural features into the model and to optimize model parameters. The final QSAR classification model was created with the Random Forest algorithm and exhibited good prediction Accuracy of 0.78 on training set and 0.80 on test set. The model representation follows FAIR principles and is available on QsarDB.org.
Assuntos
Oligoquetos , Praguicidas , Poluentes do Solo , Animais , Praguicidas/toxicidade , Teorema de Bayes , Agricultura , Solo/química , Poluentes do Solo/análiseRESUMO
Predatory myxobacteria are important soil micropredators with the potential to regulate soil microbial community structure and ecosystem function. However, the biogeographic distribution patterns, assembly processes, and potential nutrient cycling functions of myxobacteria communities in typical agricultural soils in China are still poorly understood. High-throughput sequencing, phylogenetic zero modeling, and the multi-nutrient cycling index were used to assess the biogeographic distribution, assembly processes, and soil ecosystem functions of predation myxobacteria communities in typical agricultural soils of six long-term fertilization ecological experimental stations. The results demonstrated a hump-shaped distribution of myxobacteria α-diversity along the latitudinal gradient and significant differences in myxobacteria ß-diversity in typical agricultural soils (P < 0.05). Bacterial richness, soil organic carbon, and pH were the most important predictors of myxobacteria α-diversity, whereas geographic factors and soil pH were the most significant ecological predictors of myxobacteria ß-diversity. Myxobacteria community assembly is dominated by deterministic processes, especially homogeneous selection, primarily driven by soil pH and bacterial richness. In addition, we revealed the ecological significance of myxobacteria communities in typical agricultural soil microbial networks and the potential link between myxobacteria communities and soil nutrient cycling. These findings enhance our understanding of the biogeographic distribution, community assembly, ecological predictors, and relationships with soil nutrient cycling of myxobacteria communities in typical agricultural soils, paving the way for a more predictive understanding of the effect of predatory myxobacteria communities on soil ecosystem function, which is essential for the development of sustainable agriculture.
Assuntos
Microbiota , Myxococcales , Solo/química , Filogenia , Carbono , Microbiologia do Solo , Agricultura , Bactérias , ChinaRESUMO
Mulching strategies - including plastic film mulching (FM) and straw mulching (SM) - can enhance crop yields while affecting multiple greenhouse gas (GHG) fluxes. However, most of currently published site-based studies only focus on a certain gas, resulting in an inability to spatially integrated understanding of changes in agricultural global warming potential (GWP) and greenhouse gas intensity (GHGI) caused by mulching across China. Thus, we developed an optimal model considering crop type, meteorology, soil and management variables by four machine learning methods, namely support vector machine, multilayer perceptron, random forest, and gradient boosting machine (GBM). Then we mapped the relative changes in yield and GHG fluxes caused by mulching strategies. The GBM model had the best simulation capability for yield and GHGs in China. Our result showed that FM increased yield in maize (25 %) and wheat (19 %), while SM respectively increased by 14 % and 11 %. Among the relative changes due to mulching strategies, yield and N2O emissions were mainly influenced by soil fertility and soil properties, CH4 uptakes and CO2 emissions were more affected by environmental factors. GWP in maize and wheat average increased by 40 % under FM, while SM decreased GWP by 14 % and 2 %, respectively. Besides, FM average increased GHGI in maize and wheat by 17 % and 9 %, and SM decreased GHGI by 22 % and 12 %, respectively. Spatially, FM reduced maize GWP on 19 % of cropland, while SM reduced maize and wheat GWP on 71 % and 64 % of cropland, respectively. Soil pH was significantly correlated with ΔGHGI in maize and wheat. Our analysis not only estimated for the first time the spatial effects of mulching strategies across China, but also systematically analyzes the agricultural carbon emission mitigation potential of mulching strategies, which promote the development of low-carbon agriculture based on locally appropriate mulching strategies.
Assuntos
Gases de Efeito Estufa , Zea mays , Triticum , Gases de Efeito Estufa/análise , Fazendas , Carbono , Agricultura/métodos , Solo/química , China , Óxido Nitroso/análise , Fertilizantes , Metano/análiseRESUMO
Current trends in agriculture are focused on implementing sustainable practices that avoid the use of chemical compounds. It is important to propose environmentally friendly methods, which may enhance plant growth physiology and yield without affecting soil microbial community as much. In this context, irrigation with ozonated water could be a potential strategy to reduce some chemical compounds in soils due to the degradative power of ozone. Here, we studied the impact of irrigation with ozonated water on the microbial community of a Mediterranean soil, and on Solanum lycopersicum L. agro-physiology and productivity in a greenhouse experiment. To this end, we evaluated: i) soil physicochemical properties, soil enzyme activities, microbial biomass via fatty acid analysis, microbial diversity (via amplicon sequencing), and ii) the nutrient content, physiology, phytohormone content, yield, and fruit quality of tomato plants. Our results indicate that soil physicochemical properties were significantly affected by the irrigation with ozonated water (OZ). We observed an increase in the content of total organic carbon (TOC), water-soluble nitrogen (WSN) and ammonium, and a decrease in soil pH due to the OZ treatment. In addition, a significant increase in alkaline phosphatase and fungal and bacterial biomass was also observed in the OZ treatment. It was observed that the prokaryotic community structure was affected by the OZ treatment, while that of fungi was undisturbed. The OZ treatment increased the photosynthetic rates of tomato plants and maintained water conditions when compared to control plants. The increased trans-Zeatin riboside (tZ-Rib) could provide rapid apical and root growth allowing adaptation to the new growing conditions. However, a more in-depth study on the physiological response of the plant to this treatment would be of interest, as it would help with the implementation of this strategy in agricultural fields in a safe manner, and with obtaining higher plant yields.
Assuntos
Solo , Solanum lycopersicum , Solo/química , Água , Agricultura , Bactérias , Microbiologia do SoloRESUMO
Intensification of livestock systems becomes essential to meet the food demand of the growing world population, but it is important to consider the environmental impact of these systems. To assess the potential of forage-based livestock systems to offset greenhouse gas (GHG) emissions, the net carbon (C) balance of four systems in the Brazilian Amazon Biome was estimated: livestock (L) with a monoculture of Marandu palisade grass [Brachiaria brizantha (Hochst. ex A. Rich.) R. D. Webster]; livestock-forestry (LF) with palisade grass intercropped with three rows of eucalyptus at 128 trees/ha; crop-livestock (CL) with soybeans and then corn + palisade grass, rotated with livestock every two years; and crop-livestock-forestry (CLF) with CL + one row of eucalyptus at 72 trees/ha. Over the four years studied, the systems with crops (CL and CLF) produced more human-edible protein than those without them (L and LF) (3010 vs. 755 kg/ha). Methane contributed the most to total GHG emissions: a mean of 85 % for L and LF and 67 % for CL and CLF. Consequently, L and LF had greater total GHG emissions (mean of 30 Mg CO2eq/ha/year). Over the four years, the system with the most negative net C balance (i.e., C storage) was LF when expressed per ha (-53.3 Mg CO2eq/ha), CLF when expressed per kg of carcass (-26 kg CO2eq/kg carcass), and LF when expressed per kg of human-edible protein (-72 kg CO2eq/kg human-edible protein). Even the L system can store C if well managed, leading to benefits such as increased meat as well as improved soil quality. Moreover, including crops and forestry in these livestock systems enhances these benefits, emphasizing the potential of integrated systems to offset GHG emissions.
Assuntos
Gases de Efeito Estufa , Animais , Humanos , Gases de Efeito Estufa/análise , Agricultura Florestal , Gado , Ecossistema , Árvores , Produtos Agrícolas , AgriculturaRESUMO
To simplify the process of the application of fertilizers and herbicides for farmers, a slow-release fertilizer containing cyhalofop-butyl (SFC) was developed to prolong the combined effect of the herbicide-fertilizer and achieve a synergistic effect on weeding and reducing N2O emissions. A greenhouse pot experiment was conducted using five treatments: CK (no fertilizer), CF (compound fertilizers), FC (fertilizers combined with cyhalofop-butyl), FF (film-coated compound fertilizers), and SFC (a slow-release fertilizer containing cyhalofop-butyl). The findings indicated that SFC exhibited the lowest N2O emissions, the highest paddy yield, and the highest nitrogen utilization rate among all the treatments. When compared to CF, the nitrogen release was notably delayed, leading to a significant reduction in cumulative N2O emissions under FF and SFC. When compared to CF, N2O emissions under FC were significantly decreased, suggesting that cyhalofop-butyl exerted a reduction role in N2O emissions. The SFC-treated nirK abundance was significantly lower than FF and FC, suggesting that the cyhalofop-butyl of SFC interacted with film of SFC inhibited the denitrification process in the paddy soil. Thus, the SFC reduced N2O emissions by slowing nitrogen release and down-regulating the relative abundance of nirK.
Assuntos
Fertilizantes , Nitrogênio , Fertilizantes/análise , Óxido Nitroso/análise , Solo , AgriculturaRESUMO
The utilization of slag and biochar in croplands has been proposed as a management approach to mitigate greenhouse gas (GHG) emissions, specifically methane (CH4) and nitrous oxide (N2O), from agricultural fields. However, there is limited understanding of the long-term effects of single and combined applications of slag and biochar on GHG emissions in rice paddy fields. We investigated the legacy effects of one-year applications of slag, biochar, and slag+biochar on CH4 and N2O emissions, physicochemical properties, and rice yields during a three-year period (2016-2018) in southeast China. Over the study period, the application of slag reduced CH4 emissions by 24 %, biochar by 45 %, and the combined application of slag+biochar by 44 %. Across the study period, slag, biochar, and slag+biochar applications resulted in respective N2O emissions increases of 78 %, 63 %, and 80 %. Methane emissions contributed to approximately 70 % of the global warming potential (GWP) in the paddy field, which was reduced by 20 % with biochar application and by 15 % with the combined application of slag+biochar. Additionally, the total rice yield in the slag, biochar, and slag+biochar treatments increased by 7 %, 5 %, and 10 %, respectively, compared to the control group. Based on our findings, we recommend the combined application of slag+biochar as a sustainable rice management strategy to effectively reduce GHG emissions from paddy fields while enhancing yield production.
Assuntos
Gases de Efeito Estufa , Oryza , Gases de Efeito Estufa/análise , Agricultura/métodos , Solo/química , Metano/análise , Óxido Nitroso/análiseRESUMO
In this study, artificial humic acid (AHA) was produced from rice straw at room temperature. The response surface methodology was used to investigate the response of artificial humic acid to time, liquid-solid ratio, and KOH concentration. The optimal reaction conditions were determined: reaction time of 2 h, liquid-solid ratio of 6, and KOH concentration of 1.5 mol/L. The artificial humic acid content under these conditions was 32.29 g/L, which satisfied the Chinese agricultural industry standard for water-soluble humic acid fertilizers (humic acid content ≥30 g/L). Compared with chemical fertilizers, artificial humic acid fertilizer promoted chard growth and increased soil organic matter and humic acid. The stability of artificial humic acid was better, with a retention rate of 60.47 % in the soil. Water-soluble humic acid fertilizer also promoted chard growth by increasing the relative abundance of growth-promoting bacteria such as Glutamicibacter and Pseudomonas and, as well as growth-promoting fungi such as Mortierella. The application of water-soluble humic acid fertilizers has implications for both soil improvement and the reduction of agricultural carbon emissions.
Assuntos
Oryza , Solo , Solo/química , Substâncias Húmicas/análise , Fertilizantes , Agricultura/métodos , ÁguaRESUMO
Organic manure compost offers benefits like enhanced crop yield, improved soil health, and increased soil carbon storage. However, its application might elevate direct CO2 emissions from organic matter decomposition. Beyond manure compost, significant sources of CO2 emissions in agricultural settings are from residual roots and root exudates of pre-crops, and soil carbon. Quantifying the contribution of these sources to CO2 emissions is crucial for maximizing carbon reduction in crop-livestock systems, yet field studies have not assessed this contribution. Our study at the Yucheng field station in Shandong Province, China employed 13C labeling on summer maize to generate 13C-labeled manure compost and maize root, which is used to differentiate CO2 emissions from these sources. Our results revealed novel insights into the magnitude and patterns of CO2 emissions from these sources. The emission pattern of 13C-CO2 derived from manure compost, root and root exudates was similar, but the magnitude differed. Specifically, manure compost accounted for 5 % of the total CO2 emissions, while residual roots and root exudates contributed 2 % and 57 %, respectively, suggesting a higher labile carbon content in root exudates. The remaining 36 % of CO2 emissions was derived from the soil and other sources. CO2 emission factors were 6 % for manure compost, 12 % for roots, and 2 % for root exudates. By quantifying the direct emissions from manure compost, residual roots, root exudates, and soil, our study highlights the dominant role of managing root exudates in overall CO2 emissions. These findings can guide targeted carbon reduction strategies, emphasizing the importance of managing root exudates and understanding the relative innocuousness of manure compost applications in the context of CO2 emissions. This novel research quantifies the direct contribution of individual manure compost to CO2 emissions, providing valuable data for carbon cycle models and improving understanding of CO2 contributions from new carbon inputs.
Assuntos
Fertilizantes , Esterco , Zea mays , Dióxido de Carbono/análise , Solo , Agricultura/métodos , CarbonoRESUMO
Land clearing, low levels of protection, and high biodiversity make the Brazilian Cerrado a hotspot for biological conservation. However, one of the most active agricultural frontiers in Brazil is located in this region. We thus aimed to evaluate the current trends of deforestation and fragmentation of the Cerrado, from 1986 to 2019; and the contribution of land tenure and farm size to the Cerrado conservation. We divided the Cerrado (â¼2 Mkm2) into three sub-regions and calculated the distribution and size of the fragments; core areas and edge distance; isolation and importance of the smallest fragments for reducing isolation; and connectivity for the years 1986, 1997, 2008, and 2019. We then evaluated vegetation cover and landscape metrics for public lands and private farms. Since 1986, 22 % of the Cerrado's remnant vegetation was cleared and the number of fragments increased by 20 %. Currently, 10 % of the Cerrado vegetation is under the effect of a 30 m edge. Isolation increased in all the sub-regions and smaller fragments (>100 ha) are important for landscape configuration. 10.82 % of the vegetation is preserved in public lands and 57.9 % in private farms, where 377,901.5 km2 could be legally cleared. Compared to other Brazilian regions, the northern Cerrado is relatively well connected and less fragmented but land clearing still threatens biodiversity. Public lands are important for connectivity and habitat amount but play a minor role when compared to private lands. Our results highlight that avoiding further land clearing of the Cerrado is a challenge that requires the engagement of different stakeholders at different levels.
Assuntos
Conservação dos Recursos Naturais , Ecossistema , Biodiversidade , Agricultura , Fatores Socioeconômicos , Brasil , FlorestasRESUMO
Nitrogen (N) and phosphorus (P) are limiting factors for crop production in Rwanda where food security is susceptible to inadequate agricultural techniques, especially fertilization. Understanding N and P footprints for food and their budgets under different fertilized scenarios may help to improve the nutrient use efficiency and crop yield in Rwanda, however, with little information available yet. Here, we estimated food N and P footprints and their budgets for agri-food system in Rwanda using adjusted N-P-Calculator model under fertilized, unfertilized and combined scenarios during 1961-2020. The total food N footprint per capita increased from 4.2, 3.8 and 6.4 (1960s) to 6.8, 4.9 and 9.9 kg N cap-1 yr-1 under combined, unfertilized and fertilized scenarios, respectively (2011-2020). The total food P footprint per capita increased from 0.19, 0.18 and 0.23 (1960s) to 0.31, 0.25 and 0.40 kg P cap-1 yr-1 under combined, unfertilized and fertilized scenarios, respectively (2011-2020). The total N input to croplands increased from 13.9 (1960s) to 37.0 kg N ha-1 yr-1 (2011-2020), while the total crop N uptake increased from 18.1 (1960s) to 32.5 kg N ha-1 yr-1 (2011-2020), resulting in N use efficiency decline from 99.1% (1960s) to 74.6% (2011-2020). Gaseous N losses of NH3, N2O, and NO increased from 0.9, 0.1 and 0.0 (1960s) to 7.5, 0.8 and 0.1 kg N ha-1 yr-1, respectively (2011-2020). The total P removal in harvested crops increased from 2.9 (1960s) to 5.1 kg P ha-1 yr-1 (2011-2020). The results revealed large room for crop yield expansion; and low N and P inputs are major agricultural production limitations. We suggest N and P fertilizer improvement by focusing on better management of organic animal manure and ensuring high biologically N fixed through crop rotation of legumes and cereals; lastly to increase in moderation the use of synthetic N and P fertilizers in Rwanda.
Assuntos
Nitrogênio , Fósforo , Animais , Nitrogênio/análise , Ruanda , Agricultura , Produtos Agrícolas , Fertilizantes , Esterco , SoloRESUMO
Cold regions are part of the earth's system characterized by the presence of snow and ice for at least part of the year. Many biochar applications in cold-regions agricultural sectors have been reported in China, Canada, Demark, Finland, Norway, Russia, Sweden, etc. The objective of this study was thus to comprehensively examine the previous studies of cold-region biochar technologies and their socio-economic and environmental benefits. This literature review showed that woody biochar from pine and spruce were common feedstocks with pyrolysis temperature of 550- 600 °C. 1 % and 28 t ha-1 biochar in field showed better results of promoting yield enhancement. It displayed a long-term benefit with massive economic gains and ecosystem. Moreover, the mechanism and effect of biochar were studied that instead of short-term application, a long-term application of biochar gradually improved the soil condition and generated long-term benefits due to the biochar-assisted enhancement of local ecosystem, such as improved cold-resistance of microbes and plants, promoted N uptakes, stimulated biological activities, and facilitated rhizosphere interactions. However, it should not be ignored that a short-term application could cause decline in nutrient uptake, decrease in immobilization, and trivial soil enhancement, showing an insignificant or harmful influence on the field. Though biochar generally had positive long-term effects on the field, possible influences need to be further explored to generate a best view for cold-region application of biochar with the consideration of impacts from short-term and long-term effects.
Assuntos
Agricultura , Ecossistema , Agricultura/métodos , Solo , Carvão VegetalRESUMO
Rice straw management, along with the prevalent practice of residue burning, poses multifaceted challenges with substantial environmental and human health implications. After harvest, a considerable amount of straw is left behind, often disposed of through burning, releasing several pollutants into the environment. Carbon dioxide (CO2) dominates at 70%, accompanied by methane (CH4) at 0.66%, carbon monoxide (CO) at 7%, and nitrous oxide (N2O) at 2.09%. This process further compounds issues by depleting soil nutrients like nitrogen and organic matter. This review focuses on strategies for residue management and using straw as value-added by-products. We address research gaps and offer potential recommendations for rice straw management using economically feasible and practical routes. We elaborate that to improve rice straw digestibility, utilization in mushroom cultivation, and other value-added products, low silica (Si) rice varieties must be developed using modern technologies including marker-assisted selection breeding or genome editing. Developing low Si rice could also reduce arsenic uptake by rice, as rice plants use the same transporters for the uptake of both elements. Conversely, silica is also indispensable for quality rice production; hence, optimizing silicon content in rice is worth investigating. More research is required to understand the extent of silicon's effect on the utilization of straw for various purposes. This review also discusses the importance of educating farmers about the straw burning issue and its environmental consequences. We highlight the significance of tailoring rice straw management methods to local suitability, moving away from a universal approach. More extension work is needed to encourage farmers to opt for environmentally and economically sound options for rice straw management. Policy intervention to incentivize farmers and develop technologies for the widespread use of rice straw for various industries and product development could help in the management of rice straw and will also create a circular economy.
Assuntos
Agricultura , Oryza , Humanos , Silício , Solo/química , Poluição Ambiental , Dióxido de SilícioRESUMO
BACKGROUND: For a significant subset of agricultural products, including coffee, wine and tea, sensory perceptions of terroir (i.e., characteristic flavors imparted by the growing environment) are tightly linked to the product's value. With increasing climate change, it is critical to understand how shifts in climate, such as changes in precipitation, may interact with management practices (e.g., cultivar selection) to impact sensory quality in terroir-driven crops, and what biochemical compounds may be associated with those impacts. Here, sensory quality and volatile profile composition were assessed for four Arabica coffee (Coffea arabica) cultivars grown in a field experiment where precipitation was reduced by rainout shelters, resulting in 14% lower soil moisture on average. RESULTS: Our results indicate an overall increase in yield coincident with a moderate decrease in sensory quality in response to reduced precipitation. The presence and magnitude of the sensory quality shift varied by cultivar and sensory attribute, though the Acidity attribute was consistently negatively impacted across cultivars, albeit with a high degree of uncertainty. Additionally, 31 volatile compounds were identified across green coffee samples that were variably impacted by reduced precipitation. Hierarchical clustering analysis identified patterns in volatile clustering associated with sensory attributes suggesting that reduced precipitation effects on sensory attributes may depend on nonlinear combinations of secondary metabolites. CONCLUSION: Ultimately, our results advance efforts to improve predictions of climate impacts on coffee-growing landscapes and communities and highlight the value of considering indicators of harvest value beyond yield to improve economic forecasts for agroecosystems under climate change.
Assuntos
Coffea , Café , Café/química , Coffea/química , Sensação , Agricultura , SoloRESUMO
One of the problematic outcomes of soil erosion is sedimentation in stream channels adjacent to agricultural areas. Excess sediments routinely dredged are subsequently dumped in the riparian zone, where the prolonged presence of dredged sediment piles threatens the eco-hydrological balance of the agricultural-riverine environments. Reusing dredged sediments as an amendment for adjacent agricultural fields may serve as an alternative solution. However, farmers are hesitant to use this material in their fields due to the potential for weed infestation, with the associated costs incurred by crop losses. Here, we investigate the potential for weed infestation associated with reusing dredged sediments in agriculture. The research findings validate farmers' concerns regarding the undesirable proliferation of weeds following soil amelioration with dredged sediments. We present a comprehensive protocol for assessing the necessity for weed management intervention, based on infestation potential of weeds, while specifically targeting the reduction of adverse effects caused by agricultural weeds.
Assuntos
Agricultura , Solo , Agricultura/métodos , Plantas Daninhas , Sedimentos GeológicosRESUMO
Long-term intensive cultivation has led to serious N loss and low N fertilizer utilization efficiency (NUE) in black soil areas. The lost N is not only a waste of resources but also a serious pollution threat to the environment, leading to the decline in water quality and food safety and the greenhouse effect. In the present study, a stable dual slow-release model, CPCS-Urea, was prepared by in situ polymerization using nitrapyrin, urea and melamine-formaldehyde resin as raw materials. The effect of the dual slow-release model was systematically evaluated using two consecutive years of field experiments. Five treatments were established in the field experiment: no N fertilizer (N0), urea (N180), 1 % CPEC-Urea, 0.5 % CPCS-Urea, and 1 % CPCS-Urea. The results showed that the new dual slow-release CPCS-Urea model outperformed both the use of urea and the traditional slow-release CPEC-Urea model in reducing N losses and improving NUE. The application of CPCS-Urea reduced nitrate (NO3-) leaching by 28.2 %-47.2 % and N2O emissions by 36.5 %-42.4 % and increased NUE by 20.7 %-28.5 % compared to urea application. The CPCS-Urea model modulated the activity of ammonia-oxidizing bacteria (AOB) and dissimilatory nitrate reduction to ammonium (DNRA) bacteria in soil, showing a significant decrease in AOB activity and an increase in DNRA activity. This results in a lower soil NO3--N yield and a 53.1 %-72.0 % increase in NH4+-N content, providing sufficient N for the entire growth and development cycle of maize. In short, the dual slow-release CPCS-Urea model has great application prospects for promoting agricultural development in black soil areas.
Assuntos
Compostos de Amônio , Solo , Nitratos , Fertilizantes/análise , Nitrogênio/análise , Agricultura , Ureia , Óxido Nitroso/análiseRESUMO
The idea that it is a risk to promote biodegradable mulch films on a large scale is becoming established at academic level based on a series of articles similar in approach and conclusions. However, a critical analysis shows that the results do not justify the alarmist tones. The negative effects of hand-cut pieces of virgin material added in pots at concentrations up to 714 times the application doses are ascribed to the "accumulation" and "contamination" of "residues" and "debris" of biodegradable plastics. Yet, no accumulation and no contamination of biodegradable microplastics has actually been shown. No Predicted Environmental Concentration was established, thus the use of the term risk is inappropriate. The hypothesis of transient phytotoxicity of organic matter under decomposition i.e., an artificial outcome of the experimental scheme used, was not considered. A scrupulous approach to terminology is very important for the quality of communication and for the development of innovations. Scientific communication is a delicate process in which and to avoid hyperbole, there must be strict logical and lexical consistency between results and conclusions. Guidelines on the communication of the results of studies on biodegradable mulch must be developed to avoid the spread of unjustified concerns.
Assuntos
Plásticos Biodegradáveis , Plásticos , Plásticos/toxicidade , Viés de Publicação , Microplásticos , Solo , Agricultura/métodosRESUMO
Soil environmental risk threshold of cadmium (Cd) is an important index in formulating soil protection policy. Environmental risk threshold refers to the maximal allowable critical concentration of hazardous substances in the environment. Although there is less study on how to determine soil Cd environmental risk threshold, it is a crucial indicator in formulating soil conservation policies and a key factor in assessing soil environmental quality. The main research content of the study is deducing the environmental risk threshold, aiming to provide scientific basis for the study of environmental quality standards of agricultural land and provide technical support for the protection of Cd pollution of agricultural land. The hazard concentration of 5 % species (HC5, which protects 95 % of species) was determined here using different toxicological data of Cd from 23 test endpoints, interspecific extrapolation using the species sensitivity distribution (SSD) method, and a prediction model was created on the basis of several soil parameters. According to the findings, Cd effective concentration (EC10) (Cd concentration which blocks 10 % of an endpoint's bioactivity) varied from 0.109 to 221 mg·kg-1, and the hormetic response induced by Cd reached 118 % displaying in the dose-response curve of Lolium perenne L.. Toxicology data was rectified by the aging factor considering biogeochemical processes of the newly added pollutants prior to SSD curves fitting. After that, the prediction model was created with the equation of LogHC5 = 0.147 pH + 0.067 OC -1.616. The field test properly validated the prediction model, demonstrating its ability to forecast Cd toxicity levels for various soil conditions. This study offers a scientifically sound methodology for determining the environmental risk limitation for Cd and identifies critical paths for the preservation of environmental species.