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1.
Waste Manag ; 101: 74-82, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31604160

RESUMO

Biosolarization utilizes organic amendments to produce biopesticide compounds in soil that can work in tandem with other stresses to inactivate agricultural pests. The prospect of using by-products from industrial almond processing as amendments for biosolarization was assessed. Soil mesocosms were used to simulate biosolarization using various almond by-products, application rates, and incubation times. Several potentially biopesticidal organic acids were identified and quantified in the soil, and the toxicity of soil extracts was evaluated for the root lesion nematode (Pratylenchus vulnus). It was determined that both almond hulls and a mixture of hulls and shells harbored several acids, the concentration of which was enhanced 1-7 fold via fermentation by native soil microbes. Organic acid concentration in the soil showed a significant linear relationship with the quantity of waste biomass amended. Extracts from soils containing at least 2.5% incorporated biomass by dry weight showed a 84-100% mortality of nematodes, which corresponded to acid concentrations 0.75 mg/g (2.0 g/L) or greater. This study showed that almond processing by-products - hulls and a hull and shell mixture - were suitable amendments for control of P. vulnus and potentially other soil agricultural pests in the context of biosolarization.


Assuntos
Agentes de Controle Biológico , Prunus dulcis , Agricultura , Biomassa , Solo
2.
Waste Manag ; 101: 106-115, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31605925

RESUMO

The development and design of innovative biomass waste to energy conversion processes is a key issue to pursue the implementation of circular economy and to endorse a sustainable management of agricultural land. Assessing the environmental and economic sustainability of such processes is of paramount importance to prevent the trade-off of their impacts. The present study focused on a novel biomass waste to energy conversion process based on thermocatalytic reforming (TCR). Two different agricultural waste substrates (olive wood pruning and digestate) were selected as reference cases for conversion to energy and valuable material fractions. Mass and energy balances allowed the calculation of environmental and economic indexes considering alternative scenarios for the final use of the energy and of the products obtained from the TCR conversion (i.e. syngas, bio-oil and bio-char). A sensitivity analysis was carried out to assess the robustness of results. The overall performances of the TCR process resulted strongly related to the characteristics of the biomass waste and to the possible use of the product fractions obtained in the TCR process. The use of bio-char for soil amendment, allowed by the high quality of bio-char obtained from the TCR, was a key point to improve the expected environmental and economic sustainability of the conversion process.


Assuntos
Agricultura , Madeira , Biomassa
3.
Water Res ; 168: 115154, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31630020

RESUMO

Pyrrhotite is often considered as a gangue mineral, and discarded in mine wastes and tailings. Glyphosate and fertilizer, often excessively used in agriculture, flow into water bodies with agriculture runoff, and cause pollution of water bodies. In this study, the pyrrhotite was used as a substrate in a pilot constructed wetland (CW) to remove the glyphosate and nutrients from simulated agriculture runoff. In nearly one year, the pilot pyrrhotite constructed wetland (Pyrr-CW) removed 90.3 ±â€¯6.1% of glyphosate, 88.2 ±â€¯5.1 of total phosphorus (TP) and 60.40 ±â€¯5.60% of total nitrogen (TN) on average, much higher than the control CW. The abundances of sulfur-oxidizing bacteria, such as Sulfurifustis, Sulfuriferula and Thiobacillus, were much higher in the Pyrr-CW than those in the control CW. In the Pyrr-CW goethite was produced by pyrrhotite aerobic oxidation (PAO) and pyrrhotite autotrophic denitrification (PAD) continuously and spontaneously. Higher glyphosate and TP removals were resulted from adsorption on the goethite produced, and higher TN removal was attributed to the PAD. High glyphosate and nutrients removal could keep a long term until the pyrrhotite in the Pyrr-CW was used up. The phosphorus (P) sequestered in the Pyrr-CW existed mainly in organic P, (Fe + Al)P and (Ca + Mg)P, and their order was (Fe + Al)P > organic P > (Ca + Mg)P. No heavy metal ions released from the Pyrr-CW. With higher and lasting removal rate, and lower cost, the Pyrr-CW is a promising technology for simultaneous glyphosate and nutrients removal from agricultural runoff and wastewater.


Assuntos
Nutrientes , Áreas Alagadas , Agricultura , Glicina/análogos & derivados , Nitrogênio , Fósforo , Eliminação de Resíduos Líquidos , Águas Residuárias
4.
Rev Environ Contam Toxicol ; 252: 1-50, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31451946

RESUMO

Microbe-assisted organopollutant removal, or in planta crop decontamination, is based on an interactive system between organopollutant-degrading endophytic bacteria (DEBOP) and crops in alleviating organic toxins in plants. This script focuses on the fast-growing body of literature that has recently bloomed in organopollutant control in agricultural plants. The various facets of DEBOP under study include their colonization, distribution, plant growth-promoting mechanisms, and modes of action in the detoxification process in plants. Also, an assessment of the biotechnological advances, advantages, and bottlenecks in accelerating the implementation of this decontamination strategy will be undertaken. The highlighted key research directions from this review will shape the future of agro-environmental sustainability and preservation of human health.


Assuntos
Bactérias , Produtos Agrícolas/microbiologia , Endófitos , Poluentes do Solo/metabolismo , Agricultura , Produtos Agrícolas/metabolismo , Inativação Metabólica , Desenvolvimento Vegetal
5.
Food Chem ; 302: 125366, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442705

RESUMO

Sambucus nigra is one of the richest sources of anthocyanins and other polyphenols being used industrially as a source of antioxidants, colorants, and bioactives. Although cultivars can influence elderberry composition, no study has addressed the effect of harvesting year on elderberries composition and bioactivity. The composition of the main Portuguese cultivars, "Sabugueiro", "Sabugueira" and "Bastardeira", were evaluated during three consecutive years. Harvesting year had a stronger influence on the chemical composition than cultivars, including total sugars, anthocyanins, and phenolic compounds, being related to the different climatic conditions, especially water status. "Bastardeira" was the best cultivar concerning total soluble solids, anthocyanins, polyphenols, and antioxidant activity, but containing a lower total free sugar content compared to "Sabugueiro". The results obtained in this study provide novel information from a nutritional perspective and for breeding programs aiming to select cultivars with enhanced levels of health-promoting compounds or for other industrial applications of elderberries.


Assuntos
Antocianinas/análise , Frutas/química , Fenóis/análise , Sambucus/química , Agricultura , Antioxidantes/análise , Ácido Oleanólico/análise , Extratos Vegetais/análise , Extratos Vegetais/química , Polifenóis/análise , Portugal , Sambucus nigra/química , Especificidade da Espécie , Triterpenos/análise
6.
Oecologia ; 191(4): 995-1002, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31691000

RESUMO

The responses of organisms to organic farming depend on the taxonomic group and landscape complexity. Following the intermediate landscape complexity hypothesis, organic farming can compensate for the lack of complexity in simple landscapes. Argentinian farmlands are simple with large fields and scarce linear habitat array, and conventional agriculture is almost the only agriculture practice. We hypothesize that there is an interaction effect of landscape complexity and farming practices on occupancy and species richness of small mammals in farmland of central Argentina. We selected circular landscapes under organic farming and low- and high-intensity conventional farming and quantified heterogeneity in each landscape considering different cover types (crops, resting plots, fallow land, border habitats, grasslands and man-made structures). We used multi-species occupancy models accounting for multiple seasons with a Bayesian approach to make the estimates. Landscapes under organic farms had the highest level of landscape heterogeneity. In simple Argentinian farmlands, organic farming benefited species richness and occupancy of all small mammal species. Some management strategies used in organic farming (wide and vegetated border habitats, diversity in types of production, winter cover crops, natural or semi-natural patches) should be taken into account to increase landscape complexity in conventional farming.


Assuntos
Agricultura , Biodiversidade , Animais , Argentina , Teorema de Bayes , Ecossistema , Fazendas , Mamíferos
7.
Nature ; 575(7781): 98-108, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31695208

RESUMO

Much of the Earth's biosphere has been appropriated for the production of harvestable biomass in the form of food, fuel and fibre. Here we show that the simplification and intensification of these systems and their growing connection to international markets has yielded a global production ecosystem that is homogenous, highly connected and characterized by weakened internal feedbacks. We argue that these features converge to yield high and predictable supplies of biomass in the short term, but create conditions for novel and pervasive risks to emerge and interact in the longer term. Steering the global production ecosystem towards a sustainable trajectory will require the redirection of finance, increased transparency and traceability in supply chains, and the participation of a multitude of players, including integrated 'keystone actors' such as multinational corporations.


Assuntos
Biomassa , Ecossistema , Fontes Geradoras de Energia , Retroalimentação , Abastecimento de Alimentos , Atividades Humanas , Desenvolvimento Sustentável , Agricultura/economia , Animais , Comércio/economia , Fontes Geradoras de Energia/economia , Abastecimento de Alimentos/economia , Agricultura Florestal , Água Subterrânea/análise , Atividades Humanas/economia , Humanos , Desenvolvimento Sustentável/economia
8.
Zootaxa ; 4619(3): zootaxa.4619.3.11, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31716297

RESUMO

We describe a specimen of Apostolepis phillipsi Harvey, 1999, from Vila Bela da Santíssima Trindade, Mato Grosso, establishing the first unambiguous record of the species in Brazil. The new locality is ca. 120 km from the type locality, in Bolivia. We present an updated species diagnosis, the first image of a living specimen, and the first description of A. phillipsi coloration in life. Even though the Brazilian range of A. phillipsi lies within a protected area (Parque Estadual Serra Ricardo Franco-PESRF), it is threatened by cattle raising, logging and agriculture. PESRF lacks formal delimitation and a management plan, and the Mato Grosso State Legislature is considering a decree to extinguish PESRF, which could cause the extirpation of the Brazilian range of several endemic species.


Assuntos
Serpentes , Agricultura , Animais , Bolívia , Brasil , Bovinos
9.
Zootaxa ; 4664(1): zootaxa.4664.1.1, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31716686

RESUMO

We surveyed and identified species of lady beetles from the West Bank to document their geographic distribution and understand their ecological significance. This study documents the presence of 35 species of Coccinellidae in 19 genera belonging to 10 tribes and 6 subfamilies. Seven species (mostly very rare), out of the 35 documented, are recorded for the first time in the area studied. These are Nephus (Bipunctatus) bipunctatus, N. crucifer, Scymnus (Scymnus) interruptus, S. (Parapullus) abietis, S. (Neopullus) limbatus, S. nigropictus, and S. (Pullus) suturalis. Nephus peyerimhoffi, introduced to Palestine in 1986 and later considered extirpated, is recorded from three localities in this study. The distribution of many species generally correlates with local biogeographical zones. All species recorded during the study feed on agricultural pests such as aphids and scale insects. Previously published accounts have been very limited, and while more remains to be done, this study is currently the most comprehensive in the West Bank.


Assuntos
Afídeos , Besouros , Agricultura , Animais , Ecologia , Oriente Médio
10.
Zootaxa ; 4688(1): zootaxa.4688.1.7, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31719462

RESUMO

The genus Euschistus Dallas includes 67 species restricted to the New World, and several species are registered on cultivated plants in the Nearctic and Neotropical regions. In South America, most Euschistus species are completely overlooked due to the lack of information to allow accurate identification. Here, we redescribed Euschistus taurulus Berg, including for the first time, characterization of the internal and external genitalia of both sexes. We also report original information on bionomics, review and update information on geographical distribution and host plants records. Additionally, we provide DNA barcoding sequences for E. taurulus and three other morphologically similar key-agriculture pest species in South America: Euschistus heros (Fabricius), Dichelops melacanthus (Dallas), and Dichelops furcatus (Fabricius). We discuss means for correct identification of E. taurulus and its phylogenetic position within Euschistus and other similar stink bugs; the potential economic importance of the E. taurulus is also addressed.


Assuntos
Heterópteros , Agricultura , Animais , Feminino , Masculino , Filogenia , América do Sul
11.
J Environ Qual ; 48(4): 995-1005, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589663

RESUMO

Prediction of P losses from manured agricultural fields through surface runoff and tile drainage is necessary to mitigate widespread eutrophication in water bodies. However, present water quality models are weak in predicting P losses, particularly in tile-drained and manure-applied cropland. We developed a field-scale P management model, the Root Zone Water Quality Model version 2-Phosphorus (RZWQM2-P), whose accuracy in simulating P losses from manure applied agricultural field is yet to be tested. The objectives of this study were (i) to assess the accuracy of this new model in simulating dissolved reactive phosphorus (DRP) and particulate phosphorus (PP) losses in surface runoff and tile drainage from a manure amended field, and (ii) to identify best management practices to mitigate manure P losses including water table control, manure application timing, and spreading methods by the use of model simulation. The model was evaluated against data collected from a liquid cattle manure applied field with maize ( L.)-soybean [ (L.) Merr.] rotation in Ontario, Canada. The results revealed that the RZWQM2-P model satisfactorily simulated DRP and PP losses through both surface runoff and tile drainage (Nash-Sutcliffe efficiency > 0.50, percentage bias within ±25%, and index of agreement > 0.75). Compared with conventional management practices, manure injection reduced the P losses by 18%, whereas controlled drainage and winter manure application increased P losses by 13 and 23%, respectively. The RZWQM2-P is a promising tool for P management in manured and subsurface drained agricultural field. The injection of manure rather than controlled drainage is an effective management practice to mitigate P losses from a subsurface-drained field.


Assuntos
Esterco , Fósforo , Agricultura , Animais , Canadá , Bovinos , Chuva , Movimentos da Água , Qualidade da Água
12.
J Environ Qual ; 48(4): 889-898, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589665

RESUMO

Reducing agricultural runoff is important year round, particularly on landscapes that receive wintertime applications of manure. No-tillage systems are typically associated with reduced runoff loads during the growing season, but surface roughness from fall tillage may aid infiltration on frozen soils by providing surface depressional storage. The timing of winter manure applications may also affect runoff, depending on snow and soil frost conditions. Therefore, the objective of this study was to evaluate runoff and nutrient loads during the freezing season from combinations of tillage and manure application timings. Six management treatments were tested in south-central Wisconsin during the winters of 2015-2016 and 2016-2017 with a complete factorial design: two tillage treatments (fall chisel plow vs. no-tillage) and three manure application timings (early December, late January, and unmanured). Nutrient loads from winter manure application were lower on chisel-plowed versus untilled soils during both monitoring years. Loads were also lower from manure applied to soils with less frost development. Wintertime manure applications pose a risk of surface nutrient losses, but fall tillage and timing applications to thawed soils can help reduce loads.


Assuntos
Esterco , Nutrientes , Agricultura , Congelamento , Fósforo , Estações do Ano , Solo , Wisconsin
13.
J Environ Qual ; 48(4): 931-940, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589667

RESUMO

Runoff of nutrients and erosion of soil from agricultural lands affect soil fertility and are important nonpoint contributors of P and N to surface and ground waters, yet studies of edge-of-field nutrient transport from snowmelt or rainfall runoff on frozen ground are limited. The objective of this study was to quantify the temporal and spatial variation in edge-of-field snowmelt, rain, and mixed (rain on snow) runoff events for sediment and P loadings in five agricultural subwatersheds over a 12-yr period. Edge-of-field runoff events from five subwatersheds at Pioneer Farm near Platteville, WI, ranging in size from approximately 4 to 30 ha were sampled using automated samplers from 2002 through 2014 to determine sediment and P yields (mass loads). Mean dissolved reactive P (DRP) runoff concentrations for each event type (rain = 1.24 mg L, snow = 1.90 mg L, mix = 2.23 mg L) were above total P (TP) water quality guidelines for surface waters. The percentages of TP that was DRP for snow, mixed, and rain events were 74, 84, and 39%, respectively. Although variation in total annual P yield in edge-of-field runoff was noted between years and among sites within a given year, when aggregated over the study period, the subwatersheds showed similar transport characteristics with respect to DRP and TP yield. This study highlights the importance of examining long-term datasets in quantifying annual yields and understanding the timing of DRP and TP transport for developing best management practices and improving model accuracy in cold weather agricultural systems.


Assuntos
Fósforo , Poluentes do Solo , Agricultura , Chuva , Solo , Movimentos da Água
14.
J Environ Qual ; 48(4): 966-977, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589669

RESUMO

Environmental conditions and management practices affect nutrient losses in surface runoff, but their relative impacts on phosphorus (P) loss during frozen and nonfrozen ground periods have not been well quantified. More specifically, the relative importance of manure application, tillage, and soil-test P (STP) has not been assessed at the field scale. In this study, we compiled a dataset composed of 125 site-years of data from 26 fields that were continually monitored for edge-of-field P loss during snowmelt and storm events. Regression tree analyses were performed to rank the level of influence each environmental and management factor had on nutrient loads. Dissolved P (DP) was the majority of the total P (TP) during frozen conditions, but a small portion of TP during nonfrozen conditions. Manure application had a greater influence on the flow-weighted mean concentrations (FWMCs) of TP and DP during frozen conditions than during nonfrozen conditions. No-till resulted in greater TP and DP FWMCs during frozen conditions than conventional tillage, whereas the opposite effect for TP FWMC was seen during nonfrozen conditions. However, regression tree analysis revealed that STP (0- to 5-cm depth) was the most important factor in predicting DP and TP FWMCs during frozen conditions and DP FWMC during nonfrozen conditions. Extremely high STP values were associated with late-frozen manure applications and grazed pastures. Reducing surface P loss in seasonally frozen landscapes will require prioritizing management strategies that avoid manure application through early- and late-frozen conditions and lead to a drawdown of STP, particularly in the top 5 cm.


Assuntos
Esterco , Fósforo , Agricultura , Monitoramento Ambiental , Chuva , Movimentos da Água
15.
J Environ Qual ; 48(4): 1082-1090, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589670

RESUMO

Phosphorus (P) loss from agricultural fields can contribute to water quality degradation. The current New York P index (NY-PI) scores fields on the basis of P sources and field characteristics that reflect risk of P transport (a source × transport approach). Recently, a transport × best management practice (BMP) approach was proposed, which first scores fields using landscape-driven transport factors and then offers various BMPs to reduce the score (i.e., risk of P transport). To analyze the score distribution of the current NY-PI and the incentivizing potential of the proposed structure, a database of 33,327 agricultural fields in New York was assembled in collaboration with nutrient management planners and farmers. Under the current NY-PI, no additional P could be applied to 2% of the fields, while for 3% the application rates should not exceed annual crop P removal. Flow distance (field to stream) was a major driver for NY-PI scores. The current NY-PI relies heavily on soil test P to assess runoff risk, allowing some low-P fields to receive manure independent of transport risk. A scenario evaluation showed that the proposed NY-PI limits P application on fields with high transport risk while simultaneously incentivizing adoption of BMPs in such areas. In the absence of farm-level water quality data, a farm field database can help set P index coefficients and assess implications of a new P index. This study emphasizes the value of involving stakeholders in assessing nutrient management tools, as well as the importance of using an incentive-driven approach for protecting water resources.


Assuntos
Agricultura , Fósforo , Fazendas , New York , Solo
16.
J Environ Qual ; 48(4): 1006-1015, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589671

RESUMO

There is an incentive for dairy farmers to maximize crop production while minimizing costs and environmental impacts. In cold climates, farmers have limited opportunity to balance field activities and manure storage requirements while limiting nutrient losses. A revised DeNitrification DeComposition (DNDC) model for simulating tile drainage was used to investigate fertilizer scenarios when applying dairy slurry or urea on silage corn ( L.) to examine N losses over a multidecadal horizon at locations in eastern Canada and the US Midwest. Management scenarios included timing (spring, fall, split, and sidedress) and method of application (injected [10 cm], incorporated [5 cm], and broadcast). Reactive N losses (NO from drainage and runoff, NO, and NH) were greatest from broadcast, followed by incorporated and then injected applications. Among the fertilizer timing scenarios, fall manure application resulted in the greatest N loss, primarily due to increased N leaching in non-growing-season periods, with 58% more N loss per metric ton of silage than spring application. Split and sidedress mineral fertilizer had the lowest N losses, with average reductions of 9.5 and 4.9%, respectively, relative to a single application. Split application mitigated losses more so than sidedress by reducing the soil pH shift due to urea hydrolysis and NH volatilization during the warmer June period. This assessment helps to distinguish which fertilizer practices are more effective in reducing N loss over a long-term time horizon. Reactive N loss is ranked across 18 fertilizer management practices, which could assist farmers in weighing the tradeoffs between field trafficability, manure storage capacity, and expected N loss.


Assuntos
Fertilizantes , Silagem , Agricultura , Canadá , Esterco , Nitrogênio , Zea mays
17.
J Environ Qual ; 48(4): 899-906, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589672

RESUMO

Agricultural P loss from fields is an issue due to water quality degradation. Better information is needed on the P loss in runoff from dairy manure applied in winter and the ability to reliably simulate P loss by computer models. We monitored P in runoff during two winters from chisel-tilled and no-till field plots that had liquid dairy manure applied in December or January. Runoff total P was dominated by nondissolved forms when soils were bare and unfrozen. Runoff from snow-covered, frozen soils had much less sediment and sediment-related P, and much more dissolved P. Transport of manure solids was greatest when manure was applied on top of snow and runoff shortly after application was caused by snowmelt. Dissolved P concentrations in runoff were greater when manure was applied on top of snow because manure liquid remained in the snowpack and allowed more P to be available for loss. Dissolved runoff P also increased as the amount of rain or snowmelt that became runoff (runoff ratio) increased. The SurPhos manure P runoff model reliably simulated these processes to provide realistic predictions of dissolved P in runoff from surface manure. Overall, for liquid dairy manure applied in winter, dissolved P concentrations in runoff can be decreased if manure is applied onto bare, unfrozen soil, or if runoff ratio can be reduced, perhaps through greater soil surface roughness from fall tillage. Both management approaches will allow more manure P to infiltrate into soil and less move in runoff. SurPhos is a tool that can reliably evaluate P loss for different management and policy scenarios for winter manure application.


Assuntos
Esterco , Fósforo , Agricultura , Chuva , Solo , Movimentos da Água
18.
J Environ Qual ; 48(4): 831-840, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589673

RESUMO

Snowmelt runoff often comprises the majority of annual runoff in the Canadian Prairies and a significant proportion of total nutrient loss from agricultural land to surface water. Our objective was to determine the effect of agroecosystem management on snowmelt runoff and nutrient losses from a long-term field experiment at Swift Current, SK. Runoff quantity, nutrient concentrations, and loads were estimated after a change in management from conventionally tilled wheat ( L.)-fallow (Conv W-F) to no-till wheat-fallow and subsequently no-till wheat-pulse (NT W-F/LP) and to an organic system with a wheat-green manure rotation (Org W-GM). The conversion from conventional tillage practices to no-till increased snowmelt runoff likely due to snow trapping by standing stubble after summer fallow. Relatedly, runoff after no-till summer fallow had higher dissolved P losses (0.07 kg P ha). Replacing summer fallow with a pulse crop in the no-till rotation decreased snowmelt runoff losses and nutrient concentrations. The Org W-GM treatment had the lowest P loss after stubble (0.02 kg P ha) but had high dissolved P concentrations in snowmelt following the green manure (0.55 mg P L), suggesting a contribution from incorporated crop residues. In this semiarid climate with little runoff, dissolved reactive P and NO-N loads in snowmelt runoff were smaller than those reported elsewhere on the prairies (averaging <0.05 kg P ha yr, and <0.2 kg NO-N ha yr); however, the nutrient concentrations we observed, in particular for P, even without P fertilizer addition for organic production, question the practicality of agricultural management systems in this region meeting water quality guidelines.


Assuntos
Nutrientes , Movimentos da Água , Agricultura , Canadá , Monitoramento Ambiental , Fósforo
19.
J Environ Qual ; 48(4): 1047-1056, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589676

RESUMO

Nonpoint-source pollutant surface water loading from agricultural lands, including sediment, nutrients, and pesticides, is a major concern. As contaminants entering surface water may harm endangered species, there is ongoing concern regarding the compliance of agricultural practices with the Endangered Species Act (ESA). Compliance with the ESA for the protection of threatened salmonid species is of particular concern in the Pacific Northwest region of the United States. We report here use of the Soil and Water Assessment Tool (SWAT) to characterize ecohydrology and solute transport in the Zollner Creek watershed, Willamette River basin, Oregon. Using a systems approach, integrating institutional expertise with local knowledge, we evaluated a succession of parameterization scenarios designed to sufficiently simulate watershed ecohydrology. The model was further evaluated through simulation of solute transport. Using probabilistic methods to characterize pesticide application patterns, SWAT concurrent mean estimates of daily atrazine surface water concentrations were correlated with observed instantaneous grab samples ( = 0.37) and followed the general trend of the observed data near the watershed outlet. Further development of this modeling application may provide a new understanding of continuous pesticide surface water loading at the watershed scale, allowing assessment of environmental impacts with much greater certainty, thereby facilitating consideration of refined mitigation strategies.


Assuntos
Praguicidas , Poluentes Químicos da Água , Agricultura , Modelos Teóricos , Noroeste dos Estados Unidos , Análise de Sistemas , Estados Unidos
20.
J Environ Qual ; 48(4): 1016-1028, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589678

RESUMO

Effective management of dairy manure is important to minimize N losses from cropping systems, maximize profitability, and enhance environmental sustainability. The objectives of this study were (i) to calibrate and validate the DeNitrification-DeComposition (DNDC) model using measurements of silage corn ( L.) biomass, N uptake, soil temperature, tile drain flow, NO leaching, NO emissions, and soil mineral N in eastern Canada, and (ii) to investigate the long-term impacts of manure management under climate variability. The treatments investigated included a zero-fertilizer control, inorganic fertilizer, and dairy manure amendments (raw and digested). The DNDC model overall demonstrated statistically "good" performance when simulating silage corn yield and N uptake based on normalized RMSE (nRMSE) < 10%, index of agreement () > 0.9, and Nash-Sutcliffe efficiency (NSE) > 0.5. In addition, DNDC, with its inclusion of a tile drainage mechanism, demonstrated "good" predictions for cumulative drainage (nRMSE < 20%, > 0.8, and NSE > 0.5). The model did, however, underestimate daily drainage flux during spring thaw for both organic and inorganic amendments. This was attributed to an underestimation of soil temperature and soil water under frequent soil freezing and thawing during the 2013-2014 overwinter period. Long-term simulations under climate variability indicated that spring applied manure resulted in less NO leaching and NO emissions than fall application when manure rates were managed based on crop N requirements. Overall, this study helped highlight the challenges in discerning the short-term climate interactions on fertilizer-induced N losses compared with the long-term dynamics under climate variability.


Assuntos
Fertilizantes , Zea mays , Agricultura , Canadá , Esterco , Nitrogênio , Silagem , Solo , Água
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