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1.
Ying Yong Sheng Tai Xue Bao ; 31(1): 122-128, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957388

RESUMO

Evaluating the impacts of genetically modified crops on biodiversity is a necessary step before their release to the field and obtaining environmental safety certificates. To assess the ecological safety of herbicide-resistant soybean ZUTS-33, we compared arthropod diversity, diseases occurrence, nodule number, and weed diversity through spraying herbicide or water on ZUTS-33, and its parental control receptor HC-3 and main cultivar soybean ZH-13 in a field experiment. The results showed that there was no significant difference of arthropod diversity (number of insects per 100 plants, Shannon index, Simpson index and Pielou index), diseases incidence rates and disease index, nodules and weed diversity between ZUTS-33 and non-genetically modified control soybean HC-3 and ZH-13. Spraying herbicide on ZUTS-33 had no significant effect on arthropod diversity, diseases and rhizobium compared with those treatments of spraying clear water on ZUTS-33, non-genetically modified control HC-3 and ZH-13, and the abundance of weeds were significantly decreased.


Assuntos
Herbicidas , Soja , Animais , Biodiversidade , Produtos Agrícolas , Plantas Geneticamente Modificadas
2.
Ying Yong Sheng Tai Xue Bao ; 31(1): 165-172, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957393

RESUMO

The unreasonable resource allocation and lower resource use efficiency for rice-wheat double cropping system in Jianghuai region resulted from climate change severely limit the coordinated development of annually high yield and high efficiency crops. Optimizing seasonal resource allocation through sowing date adjustment is an important way to tap the annual high-yield potential and improve resource use efficiency. To quantify the effects of sowing date of rice and wheat on annual yield and resource allocation and utilization efficiency, field experiments were conducted in 2013-2015. Results showed that compared with the conventional rice-wheat cropping system (T2), the two seasons appropriate late-cast cropping system (T3) could coordinate resource allocation in the two seasons through the sowing date adjustment, and transfer the redundant radiation and heat resources in the wheat season to the rice. The distribution rate of accumulated temperature, radiation and rainfall resources for T3 were: rice season accounted for 60.5%, 46.5% and 56.7%, wheat season accounted for 36.3%, 50.0% and 40.9%, and the ratio between two seasons was 1.67, 0.94 and 1.39, respectively. Rice yield and its proportion of annual production were significantly increased. The wheat yield was significantly decreased, with the variation range being smaller than that of rice. The total annual yield was increased by 336.3 kg·hm-2 as compared with T2. The temperature, radiation and rainfall production efficiency for rice in T3 were increased by 9.8%, 5.6% and 8.3% in compared to T2, respectively. There was no significant difference in the climate resource utilization efficiency of wheat season. The annual resource production efficiency of T3 was increased by 4.8%, 3.1% and 6.0% over the T2, respectively. Earlier (T1) or latest sowing (T4) of two seasons cropping system was not appropriate for annual yield formation and resource utilization. In summary, improving resource utilization efficiency in rice season is the key way to increase annual grain yield potential in Jianghuai region. The results provided theoretical and practical bases for the excavation of yield potential of the regional annual cropping system and the adjustment of planting structure.


Assuntos
Oryza , Triticum , Agricultura , Produtos Agrícolas , Grão Comestível , Estações do Ano
3.
Chemosphere ; 240: 124926, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726586

RESUMO

Insect pollinators such as bees and syrphid flies play a crucial role in pollinating many food crops, and their diversity and abundance may be influenced by pesticide application patterns. Over three years, we assessed the ecotoxicological impacts on the diversity and abundance of bees and syrphid flies between reduced-risk pesticide programs and standard, conventional pesticide programs in paired plots at six spatially distinct commercial apple orchards. In particular, we quantified pesticide inputs, environmental impact, and community response of bees and syrphids to these pesticide programs. Relative environmental impacts of reduced-risk versus conventional pesticide programs were calculated using Environmental Impact Quotient analysis, while ecological impacts were characterized by assessing the abundance, richness, and species assemblages of bees and syrphids. Adopting a reduced-risk pesticide program for apple pest management reduced the use (in terms of kg a.i./ha) of organophosphate and pyrethroid insecticides by approximately 97.6% and 100% respectively, but increased the use of neonicotinoid pesticides (acetamiprid, imidacloprid, thiacloprid) by 40.4% compared to the orchards under standard conventional pesticide program. Regardless of pesticide inputs, abundance, richness and species assemblages of bees and syrphids did not differ between reduced-risk and conventional pest management programs. However, the environmental impact of pesticide inputs was reduced by 89.8% in reduced-risk pesticide program. These findings suggest that the implementation of reduced-risk pesticide program may reduce pesticide environmental impact, in addition to being safer to farm workers, without adversely affecting the robust community composition of bees and syrphids in commercial apple orchards in the mid-Atlantic region.


Assuntos
Produtos Agrícolas , Malus , Controle de Pragas/métodos , Praguicidas , Polinização , Animais , Abelhas , Ecotoxicologia , Meio Ambiente , Insetos , Inseticidas , Neonicotinoides , Nitrocompostos , Piretrinas , Tiazinas
4.
Chemosphere ; 238: 124651, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31472346

RESUMO

A harbour sediment, previously remediated, was tested for soilless strawberry cultivation (Camarosa and Monterey cultivars), as an innovative, cost-effective and environment-friendly approach of sediment management. Sediments were tested as such (TS100) and mixed 1/1 (v/v) with a peat-based commercial substrate (TS50), using the peat-based medium as control (TS0). Substrates were characterized for some physicochemical properties (e.g. density, porosity and water capacity). Minerals (P, Ca, K, Na and Fe), heavy metals (Cu, Zn, Mn, Ni, Cr, Pb and Cd), aliphatic hydrocarbons (C > 12), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dibenzodioxins and dibenzofurans were analysed in substrates and fruits. Sugars and organic acids, including the ascorbic, were also determined in fruits, as quality indicators. Notwithstanding remediation, sediments showed concentrations of Zn (206 mg kg-1), C > 12 (86 mg kg-1) and PAHs (47 mg kg-1) exceeding the limits established by the Italian L.D. 152/2006, regulating the contamination of soil in green areas, thus making its relocation in the environment not permitted as such. No evidence of fruit contamination by Cr, Pb and Cd was highlighted. Moreover, Cu, Zn and Ni fruit concentrations were comparable among treatments. Conversely, Mn showed statistically higher concentrations in TS0 fruits (56-57 mg kg-1) compared to those grown in sediment-based substrates (8-20 mg kg-1). Among organic contaminants, only dioxin-like PCBs were determined in fruits, at toxic equivalent concentrations fourfold lower than the limit established by the European Union. TS100 fruits showed a yield reduction from 40 to 70% for Camarosa and Monterey, but higher sugar and ascorbic acid contents.


Assuntos
Produtos Agrícolas/normas , Monitoramento Ambiental , Fragaria/metabolismo , Frutas/química , Sedimentos Geológicos/química , Produtos Agrícolas/química , Produtos Agrícolas/crescimento & desenvolvimento , Fragaria/química , Itália , Metais Pesados/análise , Minerais/análise , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/química
5.
J Sci Food Agric ; 100(1): 25-31, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31471903

RESUMO

Nanotechnology is currently being widely employed in agriculture and horticulture. The most widely investigated and developed factor related to fruit trees is nanofertilizers (NFs), which play very important roles in increasing vegetative growth, improving reproductive growth and flowering, thereby increasing productivity, product quality and ultimately increasing shelf-life and decreasing fruit waste. These nanomaterials, which are generally sprayed at low concentrations on trees at different time intervals and in frequent sessions, are also considered as growth stimulants. Macro- and micro-scale NFs such as zinc, boron, chitosan, and fertilizer nanocomposites such as ZnFeMnB (zinc, iron, manganese, boron), NPKMg (nitrogen, phosphorus, potassium, magnesium), and calcite have been shown to significantly improve the vegetative and reproductive traits of fruit trees such as pomegranate, strawberry, mango, date, coffee and grape. Knowledge on the effects of NFs on fruit trees and biological reasons for their effects on different traits is incomplete and there is an urgent need for extensive research on these topics. © 2019 Society of Chemical Industry.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Frutas/química , Nanotecnologia/métodos , Produção Agrícola , Produtos Agrícolas/química , Fertilizantes/análise , Frutas/crescimento & desenvolvimento
7.
Sci Total Environ ; 698: 134154, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505342

RESUMO

Water scarcity, nutrient-depleted soils and pollution continue to be a major challenge worldwide and these are likely to worsen with increasing global populations particularly, in urban areas. As a result, environmental and public health problems may arise from the insufficient provision of sanitation and wastewater disposal facilities. Because of this, a paradigm shifts with regard to the sustainable management of waste disposal in a manner that could protect the environment at the same time benefits society by allowing nutrient recovery and reuse for food production is required. Hence, the use of urban wastewater for agricultural irrigation has more potential, especially when incorporating the reuse of nutrients like nitrogen and phosphorous, which are essential for crop production. Among the current treatment technologies applied in urban wastewater reuse for agriculture, hydroponic system is identified as one of the alternative technology that can be integrated with wastewater treatment. The integration of hydroponic system with municipal wastewater treatment has the advantage of reducing costs in terms of pollutants removal while reducing maintenance and energy costs required for conventional wastewater treatment. The efficiency of a hydroponic system with regard to municipal wastewater reuse is mainly linked to its capacity to allow continuous use of wastewater through the production of agricultural crops and the removal of pollutants/nutrients (nitrogen and phosphorus), resulting to increased food security and environmental protection. Moreover, the suitability of hydroponic system for wastewater treatment is derived from its capacity to minimize associated health risks to farmers, harvested crop and consumers, that may arise through contact with wastewater.


Assuntos
Agricultura/métodos , Hidroponia , Verduras/crescimento & desenvolvimento , Eliminação de Resíduos Líquidos , Irrigação Agrícola , Conservação dos Recursos Naturais , Produtos Agrícolas , Fazendeiros , Nitrogênio , Fósforo , Saneamento , Tecnologia , Águas Residuárias , Água , Purificação da Água
8.
J Environ Sci (China) ; 87: 24-38, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791497

RESUMO

Phytoremediation is a valuable technology for mitigating soil contamination in agricultural lands, but phytoremediation without economic revenue is unfeasible for land owners and farmers. The use of crops with high biomass and bioenergy for phytoremediation is a unique strategy to derive supplementary benefits along with remediation activities. Sunflower (Helianthus annuus L.) is a high-biomass crop that can be used for the phytoremediation of polluted lands with additional advantages (biomass and oil). In this study, 40 germplasms of sunflower were screened in field conditions for phytoremediation with the possibility for oil and meal production. The study was carried out to the physiological maturity stage. All studied germplasms mopped up substantial concentrations of Pb, with maximum amounts in shoot > root > seed respectively. The phytoextraction efficiency of the germplasm was assessed in terms of the Transfer factor (TF), Metal removal efficiency (MRE) and Metal extraction ratio (MER). Among all assessed criteria, GP.8585 was found to be most appropriate for restoring moderately Pb-contaminated soil accompanied with providing high biomass and high yield production. The Pb content in the oil of GP.8585 was below the Food safety standard of China, with 59.5% oleic acid and 32.1% linoleic acid. Moreover, amino acid analysis in meal illustrated significant differences among essential and non-essential amino acids. Glutamic acid was found in the highest percentage (22.4%), whereas cysteine in the lowest percentage (1.3%). Therefore, its efficient phytoextraction ability and good quality edible oil and meal production makes GP.8585 the most convenient sunflower germplasm for phytoremediation of moderately Pb-contaminated soil, with fringe benefits to farmers and landowners.


Assuntos
Biodegradação Ambiental , Helianthus/fisiologia , Chumbo , Poluentes do Solo/análise , Agricultura , Animais , Asteraceae , Biomassa , China , Produtos Agrícolas , Poluentes Ambientais , Helianthus/química , Humanos , Metais Pesados , Sementes/química , Solo
9.
Chemosphere ; 238: 124555, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31454746

RESUMO

Pesticide residues in bee products is still a major issue. However, the relations to botanical source and land use characteristics are not clear. The large variability of residues detected questions the suitability of bee-collected- and other hive materials as indicators for environmental contamination. The aim of our study was to clarify whether different beehive matrices contain similar pesticide residues, and how these are correlated with forage preferences and land use types in foraging areas. We tested bee-collected pollen, beebread, honey, nurse bees and honey bee larvae for the presence of concurrently used agricultural pesticides in Estonia. Samples were collected at the end of May and mid-July to include the main crop in northern region - winter and spring oilseed rape (Brassica napus). We saw that different beehive matrices contained various types of pesticide residues in different proportions: pollen and beebread tended to contain more insecticides and fungicides, whereas herbicides represented the primary contaminant in honey. The variations were related to collection year and time but were not related to crops as basic forage resource nor the land use type. We found few positive correlations between amount of pesticides and proportion of pollen from any particular plant family. None of these correlations were related to any land-use type. We conclude that pesticide residues in different honey bee colony components vary largely in amount and composition. The occurrence rate of pesticide residues was not linked to any particular crop.


Assuntos
Abelhas/efeitos dos fármacos , Brassica napus/crescimento & desenvolvimento , Produtos Agrícolas/crescimento & desenvolvimento , Mel/análise , Resíduos de Praguicidas/análise , Pólen/química , Animais , Brassica napus/efeitos dos fármacos , Produtos Agrícolas/efeitos dos fármacos , Estônia , Estações do Ano
10.
Huan Jing Ke Xue ; 40(10): 4725-4732, 2019 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854844

RESUMO

An eddy-covariance system combined with a semi-mechanistic model was used to analyze variations in gross primary productivity (GPP) and to simulate the impact of ozone (O3) on GPP under different levels O3 concentrations over a winter wheat field in Nanjing. The results showed that GPP was higher during the middle of the growth period and low during the early and late growth periods, reaching a maximum of 40 µmol·(m2·s)-1. Using high and low ozone sensitivity settings,O3-damage in 150, 100, 50 nL·L-1 and control treatment (CK) reduced GPP by -72%, -36%, -6%, and -10%, and by -13%, -6%, -1%, and -2%, respectively. These results provide a scientific basis for formulating defense strategies for O3 damage to crops.


Assuntos
Ozônio , Triticum , Produtos Agrícolas , Estações do Ano , Triticum/fisiologia
11.
Zootaxa ; 4565(4): zootaxa.4565.4.3, 2019 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-31716451

RESUMO

Two new species of Hemiosus (Coleoptera: Hydrophilidae) from the central cordillera of the Colombian Andes are described. Hemiosus molanoi González-Rodríguez García-Hernández sp. nov. and H. quindiensis González-Rodríguez Clarkson sp. nov. are described based in 56 adult specimens collected in river-associated sandy puddles (26 specimens of H. molanoi sp. nov.) and temporary puddles near crops (26 specimens of H. quindiensis sp. nov.). Both species are identified mainly by characteristics of the aedeagus: Hemiosus molanoi sp. nov. has subtriangular parameres, median lobe shorter than parameres and longer than appendices which are acuminate and phallobase shorter than parameres, strongly asymmetrical in basal two-fifths; H. quindiensis sp. nov. has parameres gradually tapering towards rounded apices, median lobe shorter than parameres and longer than appendices which are acuminate and phallobase shorter than parameres, strongly asymmetrical in basal half. Dorsal coloration pattern, overall shape of the meso- and metaventral process and abdominal ventrites are also informative to distinguish the new species from remaining described Hemiosus. Diagnoses, illustrations and habitat characteristics are provided.


Assuntos
Besouros , Animais , Colômbia , Produtos Agrícolas , Ecossistema , Água
12.
Zootaxa ; 4604(3): zootaxa.4604.3.3, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31717177

RESUMO

Every year the area of transgenic maize planting in Brazil expands, however, our knowledge of the fauna of herbivorous insects associated with this genetically modified crop is restricted. In this work we report for the first time the occurrence of Leucania rawlinsi Adams, 2001 and L. senescens (Möschler, 1890) (Lepidoptera: Noctuidae) in Brazil with larvae feeding on Bt and non-Bt maize silk, as well as their braconid and tachinid larval parasitoids. In order to facilitate the specific identification of these species in future studies, redescriptions of adults including high resolution images are provided. In addition, spatiotemporal distribution data of both species are presented based on systematic surveys at 13 localities in Brazil and the examination of material deposited in several scientific collections. The results are presented and discussed to contribute to the evaluation of the complex of species associated with agricultural systems that include grass crops, especially maize, including Bt varieties.


Assuntos
Mariposas , Zea mays , Animais , Proteínas de Bactérias , Brasil , Produtos Agrícolas , Endotoxinas , Proteínas Hemolisinas , Larva , Plantas Geneticamente Modificadas
13.
Yi Chuan ; 41(11): 1060-1066, 2019 Nov 20.
Artigo em Chinês | MEDLINE | ID: mdl-31735708

RESUMO

With the completion of the whole genome sequencing of major important crops, researchers have an increasing demand for high-throughput, accurate and nondestructive phenotyping technologies. The Plant Phenomics Analysis Platform (PPAP) was established in 2017 at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences. The platform has the most up-to-date comprehensive phenotyping analysis facility in China with a full spectrum of imaging systems consisting of eight units including visible light, infrared, near-infrared, root near-infrared, fluorescence, chlorophyll fluorescence, high spectral and lidar imaging. The platform has also specifically established phenotyping technologies for complex traits, such as root phenotype collection and analysis, spike and spikelet feature collection and analysis and responses under stress conditions. PPAP is dedicated to providing all-possible services for domestic and international academic communities and industrial partners engaged in plant sciences.


Assuntos
Produtos Agrícolas/genética , Fenótipo , Melhoramento Vegetal , China
14.
Nature ; 575(7781): 109-118, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31695205

RESUMO

The current trajectory for crop yields is insufficient to nourish the world's population by 20501. Greater and more consistent crop production must be achieved against a backdrop of climatic stress that limits yields, owing to shifts in pests and pathogens, precipitation, heat-waves and other weather extremes. Here we consider the potential of plant sciences to address post-Green Revolution challenges in agriculture and explore emerging strategies for enhancing sustainable crop production and resilience in a changing climate. Accelerated crop improvement must leverage naturally evolved traits and transformative engineering driven by mechanistic understanding, to yield the resilient production systems that are needed to ensure future harvests.


Assuntos
Produção Agrícola/métodos , Produção Agrícola/estatística & dados numéricos , Produtos Agrícolas/genética , Abastecimento de Alimentos/métodos , Abastecimento de Alimentos/estatística & dados numéricos , Aquecimento Global/estatística & dados numéricos , Desenvolvimento Sustentável/tendências , Aclimatação/genética , Aclimatação/fisiologia , Animais , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Produtos Agrícolas/virologia , Fertilizantes , Humanos , Doenças das Plantas/genética , Doenças das Plantas/prevenção & controle , Doenças das Plantas/estatística & dados numéricos , Chuva
15.
Ying Yong Sheng Tai Xue Bao ; 30(10): 3452-3462, 2019 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-31621232

RESUMO

To explore light energy utilization characteristics and yield effect of different legume-gramineae intercropping patterns, we set up five kinds of monocropping patterns including alfalfa, triticale, oats, maize and sorgo as reference in a field experiment. The light energy utilization chara-cteristics and productivity of four kinds of intercropping patterns including alfalfa-triticale, alfalfa-oats, alfalfa-maize and alfalfa-sorgo were examined. The contribution degree of each light energy index to yield formation was analzyed using path analysis method. The results showed that the contribution of each index of light energy to yield from large to small was as follows: leaf area index (LAI)=1.236, net photosynthetic rate (Pn)=0.519, canopy openness (DIFN)=0.302, intercellular CO2 concentration (Ci)=-0.026, stomatal conductance (gs)=-0.116, transpiration rate (Tr)=-0.188, PAR interception rate (FIPAR)=-1.708. Light use efficiency (LUE) as a comprehensive indicator of light energy utilization had the largest value (1.367). Compared with monoculture, the values of LAI, Pn, gs, Tr and FIPAR of four kinds of gramineae grasses increased under intercropping and the values of DIFN and Ci decreased, while alfalfa showed an opposite trend. Compared with monoculture, the LUE of four kinds of gramineae grasses under intercropping was significantly increased. The increase rates of triticale and oats (35.2% and 30.4%) were higher than that of maize and sorgo (28.7% and 26.3%). The decrease rates of alfalfa intercropping with triticale and oats (6.1% and 8.3%) were obviously lower than that of maize and sorgo (21.8% and 24.5%). The values of land equivalent ratio (LER) of four kinds of intercropping patterns was all greater than 1. The LER values of alfalfa-triticale and alfalfa-oat were significantly higher than those of alfalfa-maize and alfalfa-sorgo. It could be seen that LAI had the largest direct contribution to yield, followed by Pn. Among the four intercropping patterns, two patterns, alfalfa-triticale and alfalfa-oats, had greater improvement potential of light energy utilization and yield.


Assuntos
Agricultura , Produtos Agrícolas , Medicago sativa , Fotossíntese , Zea mays
16.
An Acad Bras Cienc ; 91(3): e20180578, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31596389

RESUMO

The aim of this study was to determine how often rural farmers in a watershed use no-tillage systems combined with crop rotation, contour farming and agricultural terraces. The study area was Paraná Watershed III (PB3) in the western region of Paraná State, and data from the 2006 Agricultural Census of the Brazilian Institute of Geography and Statistics were used. A frequency distribution analysis of farms as a function of the no-tillage (NT) area was conducted in combination with a cluster analysis of soil and water conservation practices (adoption of crop rotation, contour farming and agricultural terrace practices). The results showed that the farms in PB3 adopt adequate soil and water conservation practices, with 73% adopting NT combined with at least 2 other conservation practices; however, agricultural terracing was found to be the most neglected practice in the region. In addition, based on the soil and water conservation practices in the watershed, 5 groups of farms were identified, the worst of which, those located in the municipalities that mainly neglect conservation practices, live in areas with highly erodible soils.


Assuntos
Agricultura/métodos , Conservação dos Recursos Naturais/métodos , Produtos Agrícolas , Solo/química , Brasil , Água/análise , Abastecimento de Água
17.
J Environ Qual ; 48(4): 907-914, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589693

RESUMO

Cover crops (CC) have both agronomic and environmental benefits but also have the potential to increase losses of dissolved reactive P after freeze-thaw cycles (FTC). This field study, conducted over one nongrowing season (NGS) in Ontario, Canada, characterized water-extractable P (WEP) content in different CC species and compared observed changes in plant WEP content with changes in P content in soil, surface runoff, and shallow groundwater (5-25 cm). Five plots (0.4 ha) of cereal rye ( L.), oilseed radish ( L. var. Metzg Stokes), oat ( L.), and hairy vetch ( Roth) were established after winter wheat ( L.) harvest. Throughout the NGS (October-April), CC shoot tissues and surface soil were routinely sampled for WEP analyses, and groundwater and runoff water samples were collected after rain and snowmelt. Responses to FTC varied among CC species, with P released from frost-intolerant species but not frost-tolerant species. Although CC released P, the top 5 cm of soil contained greater WEP than plants at all times, and the changing WEP content in CC over the NGS was not reflected in soil or water P concentrations. These results suggest that the degree of frost exposure should be considered in the selection of CC species in cold regions; however, in temperate regions with snow cover that insulates the soil surface from heavy frost, P release from vegetation may not lead to increased P loss in runoff.


Assuntos
Produtos Agrícolas , Fósforo , Agricultura , Canadá , Chuva , Estações do Ano , Solo , Movimentos da Água
18.
J Environ Qual ; 48(4): 850-868, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589697

RESUMO

The use of cover crops and crop residues is a common strategy to mitigate sediment and nutrient losses from land to water. In cold climates, elevated dissolved P losses can occur associated with freeze-thaw of plant materials. Here, we review the impacts of cover crops and crop residues on dissolved P and total P loss in cold climates across ∼41 studies, exploring linkages between water-extractable P (WEP) in plant materials and P loss in surface runoff and subsurface drainage. Water-extractable P concentrations are influenced by plant type and freezing regimes. For example, WEP was greater in brassica cover crops than in non-brassicas, and increased with repeated freeze-thaw cycles. However, total P losses in surface runoff and subsurface drainage from cropped fields under cold climates were much lower than plant WEP, owing to retention of 45 to >99% of released P by soil. In cold climatic regions, cover crops and crop residues generally prevented soil erosion and loss of particle-bound P during nongrowing seasons in erodible landscapes but tended to elevate dissolved P loss in nonerodible soils. Their impact on total P loss was inconsistent across studies and complicated by soil, climate, and management factors. More research is needed to understand interactions between these factors and plant type that influence P loss, and to improve the assessment of crop contributions to P loss in field settings in cold climates. Further, tradeoffs between P loss and the control of sediment loss and N leaching by plants should be acknowledged.


Assuntos
Clima Frio , Fósforo , Agricultura , Produtos Agrícolas , Solo , Movimentos da Água
19.
J Environ Qual ; 48(4): 921-930, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31589699

RESUMO

In northern regions, a high proportion of annual runoff and phosphorus (P) export from cropland occurs with snowmelt. In this study, we analyze 57 site-years of field-scale snowmelt runoff data from 16 small watersheds draining fine-textured soils (clay or clay loam) in Manitoba, Canada. These fields were selected across gradients of soil P (2.4 to 26.7 mg kg, 0- to 15-cm Olsen P), tillage intensity (high frequency to long-term no-till), and fertilizer input. The strongest predictor of flow-weighted mean concentrations of total dissolved P (TDP) in snowmelt runoff was Olsen P in the top 5 cm of soil ( = 0.45, < 0.01). Residual variation in this relationship related positively to volumetric soil moisture and negatively to water yield. Although Olsen P levels were relatively consistent from year to year, suggesting control by long-term fertilization and tillage history, Olsen P stratification (ratio of 0-5/0-15 cm) increased with rates of fertilizer application. Particulate P (PP) comprised <34% of total P on average, and concentrations were not well predicted by soil or management characteristics. Loads of PP and TDP exported during snowmelt were primarily a function of water yield and size of accumulated snowpack; however, residual variation in the TDP relationship correlated positively with both soil moisture and Olsen P. Retention of runoff water on the landscape could reduce loads, but careful management of near-surface soil P is required to prevent snowmelt runoff losses of P at the source and to reduce the potential for the eutrophication of downstream aquatic ecosystems.


Assuntos
Fósforo , Solo , Agricultura , Canadá , Produtos Agrícolas , Ecossistema , Monitoramento Ambiental , Movimentos da Água
20.
J Environ Qual ; 48(5): 1281-1294, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31589725

RESUMO

The use of phosphorus (P) fertilizers in arable crop and pastoral systems is expected to change as modern agriculture is challenged to produce more food with fewer inputs. Agricultural systems models offer a dual purpose to support and integrate recent scientific advances and to identify strategies for farmers to improve nutrient efficiency. However, compared with nitrogen and carbon, advances in P modeling have been less successful. We assessed the potential opportunity of P modeling to increase P efficiency for modern agriculture and identified the current challenges associated with modeling P dynamics at the field scale. Three major constraints were (i) a paucity of detailed field datasets to model strategies aimed at increasing P use efficiency, (ii) a limited ability to predict P cycling and availability under the local effects of climate change, and (iii) a restricted ability to match measured soil P fractions to conceptual and modelable pools in soils with different mineral properties. To improve P modeling success, modelers will need to walk a tightrope to balance the roles of assisting detailed empirical research and providing practical land management solutions. We conclude that a framework for interdisciplinary collaboration is needed to acquire suitable datasets, continually assess the need for model adjustment, and provide flexibility for progression of scientific theory. Such an approach is likely to advance P management for increased P use efficiency.


Assuntos
Fósforo , Solo , Agricultura , Produtos Agrícolas , Fertilizantes
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