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1.
Nat Commun ; 11(1): 4295, 2020 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-32908130

RESUMO

Recent expansion of croplands in the United States has caused widespread conversion of grasslands and other ecosystems with largely unknown consequences for agricultural production and the environment. Here we assess annual land use change 2008-16 and its impacts on crop yields and wildlife habitat. We find that croplands have expanded at a rate of over one million acres per year, and that 69.5% of new cropland areas produced yields below the national average, with a mean yield deficit of 6.5%. Observed conversion infringed upon high-quality habitat that, relative to unconverted land, had provided over three times higher milkweed stem densities in the Monarch butterfly Midwest summer breeding range and 37% more nesting opportunities per acre for waterfowl in the Prairie Pothole Region of the Northern Great Plains. Our findings demonstrate a pervasive pattern of encroachment into areas that are increasingly marginal for production, but highly significant for wildlife, and suggest that such tradeoffs may be further amplified by future cropland expansion.


Assuntos
Animais Selvagens , Conservação dos Recursos Naturais , Custos e Análise de Custo/estatística & dados numéricos , Produção Agrícola/tendências , Produtos Agrícolas/economia , Animais , Biodiversidade , Borboletas , Produção Agrícola/economia , Produção Agrícola/estatística & dados numéricos , Dispersão Vegetal , Análise Espaço-Temporal , Estados Unidos
2.
PLoS One ; 15(9): e0237460, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32911506

RESUMO

Infection of wheat by Fusarium species can lead to Fusarium Head Blight (FHB) and mycotoxin contamination, thereby reducing food quality and food safety, and leading to economic losses. Agronomic management through the implementation of various pre-harvest measures can reduce the probability of Fusarium spp. infection in the wheat field. To design interventions that could stimulate wheat farmers to (further) improve their agronomic management to reduce FHB, it is key to understand farmers' behaviour towards adapting their management. The aim of this paper was to understand the intention, underlying behavioural constructs, and beliefs of Dutch wheat farmers to adapt their agronomic management to reduce FHB and mycotoxin contamination in wheat, applying the Theory of Planned Behaviour (TPB). Data were collected from 100 Dutch wheat farmers via a questionnaire. The standard TPB analysis was extended with an assessment of the robustness of the belief results to account for the statistical validity of the analysis on TPB beliefs (i.e. to address the so-called expectancy-value muddle). Forty-six percent of the farmers had a positive intention to change their management in the next 5 years. The two behavioural constructs significantly related to this intention were attitude and social norm, whereas association with the perceived behavioural control construct was insignificant indicating that farmers did not perceive any barriers to change their behaviour. Relevant attitudinal beliefs indicated specific attributes of wheat, namely yield, quality and safety (lower mycotoxin contamination). This indicates that strengthening these beliefs-by demonstrating that a change in management will result in a higher yield and quality and lower mycotoxin levels-will result in a stronger attitude and, subsequently, a higher intention to change management. Interventions to strengthen these beliefs should preferably go by the most important referents for social norms, which were the buyers and the farmer cooperatives in this study.


Assuntos
Produção Agrícola/métodos , Fusarium/isolamento & purificação , Doenças das Plantas/prevenção & controle , Triticum/microbiologia , Agricultura/métodos , Controle Comportamental , Fazendeiros , Qualidade dos Alimentos , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Intenção , Doenças das Plantas/microbiologia , Normas Sociais , Inquéritos e Questionários
3.
Annu Rev Phytopathol ; 58: 277-311, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32853099

RESUMO

The loss of methyl bromide as a soil fumigant and minimal advances in the development and registration of new chemical fumigants has resulted in a resurgence of interest in the application of organic amendments (OAs) for soilborne plant pathogen and plant-parasitic nematode management. Significant progress has been made in the characterization of OAs, application of strategies for their use, and elucidation of mechanisms by which they suppress soilborne pests. Nonetheless, their utility is limited by the variability of disease control, expense, and the logistics of introducing them into crop production systems. Recent advances in molecular techniques have led to significant progress in the elucidation of the role of bacteria and fungi and their metabolic products on disease suppression with the addition of OAs. Biosolarization and anaerobic soil disinfestation, developed to manipulate systems and favor beneficial microorganisms to maximize their impact on plant pathogens, are built on a strong historical research foundation in OAs and the physical, chemical, and biological characteristics of disease-suppressive soils. This review focuses on recent applications of OAs and their potential for the management of soilborne plant pathogens and plant-parasitic nematodes, with emphasis primarily on annual fruit and vegetable production systems.


Assuntos
Nematoides , Animais , Produção Agrícola , Fungos , Solo , Microbiologia do Solo
4.
PLoS One ; 15(8): e0237744, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32841246

RESUMO

Both the Mediterranean (MED) species of the Bemisia tabaci whitefly complex and the greenhouse whitefly (Trialeurodes vaporariorum, TV) are important agricultural pests. The two species of whiteflies differ in many aspects such as morphology, geographical distribution, host plant range, plant virus transmission, and resistance to insecticides. However, the molecular basis underlying their differences remains largely unknown. In this study, we analyzed the genetic divergences between the transcriptomes of MED and TV. In total, 2,944 pairs of orthologous genes were identified. The average identity of amino acid sequences between the two species is 93.6%. The average nonsynonymous (Ka) and synonymous (Ks) substitution rates and the ratio of Ka/Ks of the orthologous genes are 0.0389, 2.23 and 0.0204, respectively. The low average Ka/Ks ratio indicates that orthologous genes tend to be under strong purified selection. The most divergent gene classes are related to the metabolisms of xenobiotics, cofactors, vitamins and amino acids, and this divergence may underlie the different biological characteristics between the two species of whiteflies. Genes of differential expression between the two species are enriched in carbohydrate metabolism and regulation of autophagy. These findings provide molecular clues to uncover the biological and molecular differences between the two species of whiteflies.


Assuntos
Produção Agrícola , Genes de Insetos/genética , Especiação Genética , Hemípteros/genética , Proteínas de Insetos/genética , Sequência de Aminoácidos/genética , Substituição de Aminoácidos/genética , Aminoácidos/metabolismo , Animais , Hemípteros/metabolismo , Proteínas de Insetos/metabolismo , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Região do Mediterrâneo , Anotação de Sequência Molecular , RNA-Seq , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Vitaminas/metabolismo , Xenobióticos/metabolismo
5.
Ecotoxicol Environ Saf ; 202: 110950, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800226

RESUMO

Human exposure to methylmercury (MeHg) through rice consumption is raising health concerns. It has long been recognized that MeHg found in rice grain predominately originated from paddy soil. Anaerobic conditions in paddy fields promote Hg methylation, potentially leading to high MeHg concentrations in rice grain. Understanding the transformation and migration of Hg in the rice paddy system, as well as the effects of farming activities, are keys to assessing risks and developing potential mitigation strategies. Therefore, this review examines the current state of knowledge on: 1) sources of Hg in paddy fields; 2) how MeHg and inorganic Hg (IHg) are transformed (including abiotic and biotic processes); 3) how IHg and MeHg enter and translocate in rice plants; and 4) how regular farming activities (including the application of fertilizer, cultivation methods, choice of cultivar), affect Hg cycling in the paddy field system. Current issues and controversies on Hg transformation and migration in the paddy field system are also discussed.


Assuntos
Produção Agrícola/métodos , Monitoramento Ambiental/métodos , Mercúrio/análise , Compostos de Metilmercúrio/análise , Oryza/efeitos dos fármacos , Poluentes do Solo/análise , Fertilizantes/análise , Humanos , Mercúrio/metabolismo , Compostos de Metilmercúrio/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Solo/química , Poluentes do Solo/metabolismo
6.
PLoS One ; 15(8): e0236326, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822363

RESUMO

This study aimed to test whether or not where people come from and move to impacts their method for dealing with stress. We investigated this research question among newcomers crossing between the rice and wheat farming regions in China-south and north China, respectively. New evidence suggests wheat-farming agriculture fosters a coping strategy of changing the environment (primary coping), while rice-farming regions foster the converse strategy of fitting into the environment (secondary coping). Using two longitudinal studies on newcomers at universities located in both the rice and wheat farming regions, we hypothesized that students from south China (rice region) at a university in north China (wheat region) would use more primary coping and it would lead to better adaptation (Study 1). In contrast, students from wheat-farming regions moving to a rice university would benefit from secondary coping as an effective strategy for buffering stress (Study 2). Results indicated that for students from rice-farming regions who were studying universities in wheat-farming regions, secondary coping was damaging and attenuated the stress-adaptation relationship. However, in study 2, the reverse was found, as secondary coping was found to buffer the negative effects of stress on sociocultural adaptation for students from wheat-farming regions who were studying at universities in rice-farming regions. This study lends further support to the theory that ecological factors impact how individuals cope with the acculturative stress of moving to a new environment.


Assuntos
Aculturação , Adaptação Psicológica , Produção Agrícola , Comparação Transcultural , Migração Humana , Adolescente , China , Produtos Agrícolas , Fazendas , Feminino , Geografia , Humanos , Estudos Longitudinais , Masculino , Oryza , Estudantes/psicologia , Triticum , Universidades , Adulto Jovem
7.
PLoS One ; 15(8): e0237337, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760125

RESUMO

Mobile phone use is increasing in Sub-Saharan Africa, spurring a growing focus on mobile phones as tools to increase agricultural yields and incomes on smallholder farms. However, the research to date on this topic is mixed, with studies finding both positive and neutral associations between phones and yields. In this paper we examine perceptions about the impacts of mobile phones on agricultural productivity, and the relationships between mobile phone use and agricultural yield. We do so by fitting multilevel statistical models to data from farmer-phone owners (n = 179) in 4 rural communities in Tanzania, controlling for site and demographic factors. Results show a positive association between mobile phone use for agricultural activities and reported maize yields. Further, many farmers report that mobile phone use increases agricultural profits (67% of respondents) and decreases the costs (50%) and time investments (47%) of farming. Our findings suggest that there are opportunities to target policy interventions at increasing phone use for agricultural activities in ways that facilitate access to timely, actionable information to support farmer decision making.


Assuntos
Uso do Telefone Celular/estatística & dados numéricos , Produção Agrícola/estatística & dados numéricos , Eficiência , Fazendeiros/estatística & dados numéricos , Fazendas/estatística & dados numéricos , Adulto , Uso do Telefone Celular/economia , Produção Agrícola/economia , Fazendas/economia , Feminino , Humanos , Renda/estatística & dados numéricos , Invenções , Masculino , População Rural/estatística & dados numéricos , Autorrelato/estatística & dados numéricos , Tanzânia , Zea mays
8.
PLoS One ; 15(8): e0237245, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32780782

RESUMO

Straw mulching has been widely adopted in dryland cropping but its effect on soil respiration and microbial communities under warming are not well understood. Soil samples were collected from a corn field with straw mulching (SM) for nine years and without straw mulching (CK), and incubated at 15°C, 25°C, and 35°C for 60 days. Soil respiration, C fractions and bacterial and fungal community structure were measured SM had greater soil organic carbon and potential C mineralization and a similar microbial biomass carbon throughout the incubation when compared with CK. Soil respiration increased with increasing temperature and its temperature sensitivity (Q10) was lower with SM than CK. Similar microbial community composition was found in the soils with SM and CK before incubation. However, SM had a greater bacterial richness and the relative abundances of Proteobacteria, Acidobacteria, Nitrospirae, Planctomycetes, Bacteroidetes, and Basidiomycota, but lower relative abundances of Actinobacteria, Chloroflexi, and Ascomycota than CK after incubation. Bacterial richness and diversity were greater at 15°C and 25°C than 35°C, but there was no difference in fungal richness and diversity among the incubation temperatures. As temperature increased, the relative abundances of Chloroflexi, Acidobacteria, and Bacteroidetes decreased, but Gemmatimonadetes and Ascomycota increased, and were significantly correlated with soil C fractions and respiration. These findings indicated that the effect of straw mulching on soil C cycling and microbial community structure can be highly modified by increasing temperature.


Assuntos
Produção Agrícola/métodos , Microbiologia do Solo , Solo/química , Bactérias/classificação , Bactérias/isolamento & purificação , Carbono/análise , Fungos/classificação , Fungos/isolamento & purificação , Microbiota , Micobioma , Temperatura , Zea mays/crescimento & desenvolvimento
9.
PLoS One ; 15(8): e0237234, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32810176

RESUMO

China implemented the Action Plan for the Zero Increase of Fertilizer Use in 2015, which led to a decrease in fertilizer use. However, Will fertilizer use continue to reduce? With data obtained from 2006 to 2017, the paper used the logarithmic mean Divisia index (LMDI) method to analyze the scale effect, intensity effect and structural effect of fertilizer use change in China from three aspects: crops, regions and fertilizer types. Our finding suggests that (1) The intensity effect was the most critical factor affecting the decline in fertilizer use in China. (2) The sowing scale and fertilization intensity of grain, vegetables and fruits had the most significant driving effect on fertilizer reduction. (3) The three effects of each region were different in space, and the eastern region contributed most to the fertilizer decrement. (4) Nitrogen fertilizer and compound fertilizer had the most considerable influence on fertilizer reduction, especially in the sowing scale and fertilization intensity since 2009. The government should establish a fertilizer reduction management system, which includes scale control, intensity reduction, structural adjustment and other measures.


Assuntos
Produção Agrícola , Produtos Agrícolas/crescimento & desenvolvimento , Fertilizantes/provisão & distribução , Algoritmos , China , Produção Agrícola/economia , Produção Agrícola/métodos , Desenvolvimento Econômico , Nitrogênio/provisão & distribução
10.
Ecotoxicol Environ Saf ; 205: 111162, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32836158

RESUMO

The mechanisms of intercropping increasing plant biomass, cadmium accumulation, and organic acids secreted in rhizosphere soil are still unclear. Oilseed rape and intercrops were grown in boxes separated either with no barrier between the compartments or by a nylon mesh barrier (37 µm) to license partial root interaction, or a solid barrier to stop any root interactions. Two intercropping systems (oilseed rape-faba bean and oilseed rape-ryegrass) were carried out in soil with Cd content of 5 mg/kg. The intermingling of roots between oilseed rape and faba bean enhanced the biomass of oilseed rape. However, the biomass was negatively affected implying the higher nutrient apportionment to the ryegrass than oilseed rape. Oilseed rape intercropping with both faba bean and ryegrass played a positive role in the shoot Cd concentration of oilseed rape. The intermingling of roots played a positive role in the citric and malic acids when intercropping with faba bean. A remarkable increase in water-soluble Cd and DTPA-Cd content was observed during oilseed rape-faba bean complete root interaction treatment, up to 175.00% and 46.65%, respectively, which compare with the monoculture treatment. In both systems, the translocation factor values were higher for oilseed rape (O-F system) than for the other test plants and were always >1. Thus the Cd removal potential of oilseed rape can be further improved in the future by optimizing agronomic practices and intercropping with faba bean.


Assuntos
Brassica napus/crescimento & desenvolvimento , Cádmio/metabolismo , Produção Agrícola/métodos , Lolium/crescimento & desenvolvimento , Poluentes do Solo/metabolismo , Vicia faba/crescimento & desenvolvimento , Bioacumulação , Biomassa , Brassica napus/metabolismo , China , Lolium/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Rizosfera , Solo/química , Vicia faba/metabolismo
11.
PLoS One ; 15(7): e0235872, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32673343

RESUMO

Fertilizer discharge process is a critical part of fertilizer application, as it affects the fertilizer discharge rate and uniformity of fertilizer application. In this study, a spiral grooved-wheel fertilizer discharge device was designed to replace the conventional straight grooved-wheel. Comparisons of the fertilizer discharge performance of the two grooved-wheel types were performed through tests and simulations using the discrete element method (DEM). The discharge performance of the two discharge devices was assessed by measuring the discharge mass rate, discharge uniformity, and the falling velocity of the fertilizer particles. Results showed that under similar conditions, the fertilizer discharge mass rate of the spiral grooved-wheel was higher than that of the straight grooved-wheel. The fertilizer discharge uniformity of the spiral grooved-wheel was much better than that of the straight grooved-wheel. The average falling velocity of fertilizer particles through the discharge spout was higher under the spiral grooved-wheel. The relative errors between the test and simulation results for the discharge mass rates, discharge uniformity, and particle falling velocities of the spiral grooved-wheel were all less than 10%. The developed spiral grooved-wheel exhibited a better performance than the conventional straight grooved-wheel, in all the aspects examined. The results serve as a theoretical basis for guiding the design of high-performance fertilizer applicators.


Assuntos
Produção Agrícola/instrumentação , Fertilizantes , Simulação por Computador , Produção Agrícola/métodos
12.
PLoS One ; 15(7): e0235661, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32702038

RESUMO

As urban areas expand around the world, there are growing efforts to restore and protect natural and agricultural systems for the multitude of ecosystem services they provide to urban communities. This study presents a researcher-farmer collaboration in a highly urbanized area of O'ahu focused on understanding the historical and current challenges and opportunities faced by a culturally and socially valued spring-dependent urban farm, Sumida Farm, which produces the majority of the state of Hawai'i's watercress. We conducted a long-term trend analysis (25 years) of factors identified by the farmers to be important historical drivers of crop yield, including groundwater pumping, pest outbreaks, temperature, Oceanic Niño Index, and precipitation. We combined this analysis with a year of intensive spring water sampling on the farm to evaluate nutrient and contaminant composition and flow to understand water-related stressors, as well as evaluate the potential of the farm to provide nutrient retention services. We found negative correlations between historical crop yields and increases in the Oceanic Niño Index, temperature thresholds, and pest outbreaks. Despite the surrounding urbanization, we found on-farm water quality to be very high, and microbial analyses revealed an abundance of denitrifiers (nirS gene) suggesting that the farm provides a nutrient retention service to downstream systems. Finally, we found that socio-cultural values including heritage value, aesthetic value, and educational value are increasingly important for the Sumida family and surrounding community. These socio-cultural benefits alongside highly valued local food production and nutrient retention services are essential for continued community and political support. Collectively, our study demonstrates that challenges facing urban agricultural systems shift through time, and that recognition of the beyond crop-yield benefits of these systems to urban communities is essential to their long-term survival.


Assuntos
Agricultura , Brassicaceae/crescimento & desenvolvimento , Bactérias/genética , Bactérias/isolamento & purificação , Produção Agrícola , Ecossistema , Fazendas , Hawaii , Ciclo do Nitrogênio , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Microbiologia do Solo , Urbanização , Qualidade da Água
13.
PLoS One ; 15(7): e0235868, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32716963

RESUMO

Cover crop mixtures can provide multiple ecosystem services but provisioning of these services is contingent upon the expression of component species in the mixture. From the same seed mixture, cover crop mixture expression varied greatly across farms and we hypothesized that this variation was correlated with soil inorganic nitrogen (N) concentrations and growing degree days. We measured fall and spring biomass of a standard five-species mixture of canola (Brassica napus L.), Austrian winter pea (Pisum sativum L), triticale (x Triticosecale Wittm.), red clover (Trifolium pratense L.) and crimson clover (Trifolium incarnatum L.) seeded at a research station and on 8 farms across Pennsylvania and New York in two consecutive years. At the research station, soil inorganic N (soil iN) availablity and cumulative fall growing degree days (GDD) were experimentally manipulated through fertilizer additions and planting date. Farmers seeded the standard mixture and a "farm-tuned" mixture of the same five species with component seeding rates adjusted to achieve farmer-desired services. We used Structural Equation Modeling to parse out the effects of soil iN and GDD on cover crop mixture expression. When soil iN and fall GDD were high, canola dominated the mixture, especially in the fall. Low soil iN favored legume species while a shorter growing season favored triticale. Changes in seeding rates influenced mixture composition in fall and spring but interacted with GDD to determine the final expression of the mixture. Our results show that when soil iN availability is high at the time of cover crop planting, highly competitive species can dominate mixtures which could potentially decrease services provided by other species, especially legumes. Early planting dates can exacerbate the dominance of aggressive species. Managers should choose cover crop species and seeding rates according to their soil iN and GDD to ensure the provision of desired services.


Assuntos
Produção Agrícola/métodos , Modelos Estatísticos , Nitrogênio/análise , Estações do Ano , Solo/química , Brassica/crescimento & desenvolvimento , Medicago/crescimento & desenvolvimento , Ervilhas/crescimento & desenvolvimento , Triticale/crescimento & desenvolvimento
14.
PLoS One ; 15(7): e0235397, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32628713

RESUMO

Appropriate flowering and maturity time are important for soybean production. Four maturity genes E1, E2, E3 and E4 have been molecularly identified and found to play major roles in the control of flowering and maturity of soybean. Here, to further investigate the effect of different allele combinations of E1-E4, we performed Kompetitive Allele Specific PCR (KASP) assays based on single nucleotide polymorphisms (SNPs) at these four E loci, and genotyped E1-E4 genes across 308 Chinese cultivars with a wide range of maturity groups. In total, twenty-one allele combinations for E1-E4 genes were identified across these Chinese cultivars. Various combinations of mutations at four E loci gave rise to the diversity of flowering and maturity time, which were associated with the adaptation of soybean cultivars to diverse geographic regions and farming systems. In particular, the cultivars with mutations at all four E loci reached flowering and maturity very early, and adapted to high-latitude cold regions. The allele combinations e1-as/e2-ns/e3-tr/E4, E1/e2-ns/E3/E4 and E1/E2/E3/E4 played important roles in the Northeast China, Huang-Huai-Hai (HHH) Rivers Valley and South China regions, respectively. Notably, E1 and E2, especially E2, affected flowering and maturity time of soybean significantly. Our study will be beneficial for germplasm evaluation, cultivar improvement and regionalization of cultivation in soybean production.


Assuntos
Adaptação Fisiológica/genética , Regulação da Expressão Gênica de Plantas , Genes Controladores do Desenvolvimento , Locos de Características Quantitativas , Soja/fisiologia , Alelos , China , Produção Agrícola , Fazendas , Flores/crescimento & desenvolvimento , Genes de Plantas , Variação Genética , Genótipo , Geografia , Fotoperíodo , Fatores de Tempo
15.
J Environ Manage ; 270: 110938, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32721356

RESUMO

The application of biogas slurry, from anaerobic digestion of livestock excreta, to cropland has proven to be an effective mechanism for recycling nutrients within farms. However, the potential pollution of heavy metals from repeated biogas slurry fertilization has not received much attention. Here we present the results of a field experiment under rice-wheat rotation demonstrating the accumulation, speciation distribution and plant uptake of heavy metals (Cu, Zn, Pb and Cd) in soil following biogas slurry application. The treatments were: zero biogas slurry application (BS0), and biogas slurry application for three (BS3) and five (BS5) years, at a rate of 450 m3 ha-1 y-1. Our findings show that biogas slurry fertilization resulted in accumulation of Cu and Zn in the soil. The concentrations of soil Cu and Zn under BS5 were, respectively, 38 and 29% greater in the wheat season and 35 and 35% greater in the rice season relative to BS0 (p < 0.05). The bioavailability of soil Cu and Zn increased following biogas slurry application. Plant uptake of Cu and Zn to all parts of wheat and rice plants (excluding Cu in wheat straw) increased with the years of biogas slurry application (p < 0.05), and the concentration of Cd in wheat grain was significantly greater in BS5 relative to BS0 (p < 0.05). After five years of biogas slurry fertilization, concentrations of Cu, Zn, Pb and Cd in wheat grains were 3.28, 25.19, 0.11 and 0.053 mg kg-1 and 4.24, 33.78, 0.12 and 0.035 mg kg-1 for rice grains, respectively, all within the safety limits. Our results demonstrate that repeated biogas slurry fertilization for five years has a relatively low pollution risk of heavy metals. However, long-term field monitoring and co-application with metal-immobilizing materials are required to ensure the safety of its application to cropland.


Assuntos
Metais Pesados/análise , Oryza , Poluentes do Solo/análise , Biocombustíveis , China , Produção Agrícola , Monitoramento Ambiental , Solo , Triticum
16.
Environ Pollut ; 266(Pt 3): 115082, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32629310

RESUMO

This work evaluated the debromination and uptake of 14C-labeled BDE-209 in rice cultivars grown in anoxic soil for 120 days (d) followed by cultivation of vegetables (peanut, eggplant and pepper) in oxic soil (120 d). Degradation of BDE-209 to lower polybrominated diphenyl ethers (PBDEs) occurred in cultivated soils, and more metabolites were released in oxic soil than in anoxic soil. The crop rotation from anoxic to oxic greatly enhanced the dissipation of BDE-209 in the soil (P < 0.05), in which the dissipation in anoxic soil planted with Huanghuazhan (HHZ, indica) and Yudao 1 (YD1, indica) were 6.8% and 2.4%, respectively, while in oxic soil with peanut and pepper were increased to 25.8% and 21.7%, respectively. The crop rotation also enhanced the degradation of BDE-209 in the soil, the recovered BDE-209 in soil after 120 d anoxic incubation with YD1 was 81.1%, but it decreased to 47.8% and 45.8% after another 120 d oxic incubation. Bioconcentration factors were between 0.23 and 0.36 for rice, eggplant and pepper but reached to 0.5 in peanut, which contains more lipids in the edible portion than the other test crops. The estimated daily intake for vegetables was 0.01-0.07 µg BDE-209-equivalent kg-1 bw day-1, which is at least two orders of magnitude below the maximum acceptable oral dose (7 µg kg-1 bw day-1). Our work confirms that crop rotation from rice to vegetable enhanced the dissipation and debromination of BDE-209 in the soil, and indicate that sequential anoxic-oxic rotation practice is considered to be effective in remediation of environmental pollutants.


Assuntos
Oryza , Poluentes do Solo/análise , Produção Agrícola , Produtos Agrícolas , Éteres Difenil Halogenados/análise , Solo
17.
PLoS One ; 15(7): e0236677, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32716970

RESUMO

Florida strawberry growers frequently relay-crop (RC) vegetables with strawberry to offset high input costs. Relay-cropping consists of planting two crops at different times on the same raised bed which helps growers' lower risk due to diversification and maximize economic returns. Four separate experiments on relay cropping strawberry with jalapeño pepper and cantaloupe were conducted at Balm, Florida, in 2016-17 and 2017-18. The objective was to a) determine the effects of relay-cropping on crop yields, b) optimize pepper and cantaloupe planting date, and c) optimize the strawberry termination date when relay cropping with vegetables. Strawberry yields were unaffected by the presence of vegetables. Pepper yields were unaffected by the presence of strawberries, but cantaloupes yields were significantly (p = 0.0250) lower when planted with strawberry. Early January to early-February were the optimum dates to transplant pepper with strawberries transplanted in October but date of planting did not affect cantaloupe yield. Early January to early-February transplant dates for pepper resulted in net profits of around $23000-38000/ha in 2016-17 compared to the baseline treatment (strawberries alone). However, in 2017-18 all of the planting dates of pepper with strawberry except January 4 resulted in losses of $2000-18000/ha. In 2016-17, cantaloupes planted in late January and early February resulted in profits of $2986.3 and 2705.1/ha, respectively. All other planting dates resulted in loses compared to baseline treatment. In 2017-18, all the planting dates resulted in net profits of around $6700-14500/ha. In conclusion, cantaloupe and jalapeño pepper can be relay cropped with strawberry with no negative effects on strawberry yield. However, early planting dates tend to maximize economic return.


Assuntos
Capsicum/crescimento & desenvolvimento , Produção Agrícola/economia , Cucumis melo/crescimento & desenvolvimento , Fragaria/crescimento & desenvolvimento , Florida , Estações do Ano
18.
PLoS One ; 15(7): e0235620, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645043

RESUMO

Accurate information about the spatiotemporal variability of actual crop evapotranspiration (ETa), crop coefficient (Kc) and water productivity (WP) is crucial for water efficient management in the agriculture. The Earth Engine Evapotranspiration Flux (EEFlux) application has become a popular approach for providing spatiotemporal information on ETa and Kc worldwide. The aim of this study was to quantify the variability of water consumption (ETa) and the Kc for an irrigated commercial planting of soybeans based on the EEFlux application in the western region of the state of Bahia, Brazil. The water productivity (WP) for the fields was also obtained. Six cloud-free images from Landsat 7 and 8 satellites, acquired during the 2016/17 soybean growing season were used and processed on the EEFlux platform. The ETa from EEFlux was compared to that of the modified FAO (MFAO) approach using the following statistical metrics: Willmot's index of agreement (d-index), root mean square error (RMSE), mean absolute error (MAE) and mean bias error (MBE). The Kc from EEFlux was compared to the Kc used in the soybean field (Kc FAO-based) and to the Kc values obtained in different scientific studies using the d-index. A similar procedure was performed for WP. Our results reveal that EEFlux is able to provide accurate information about the variability of ETa and the Kc of soybean fields. The comparison between ETa EEFlux and ETa MFAO showed good agreement based on the d-index, with values of 0.85, 0.83 and 0.89 for central pivots 1, 2 and 3, respectively. However, EEFlux tends to slightly underestimate ETa. The Kc EEFlux showed good accordance with the Kc values considered in this study, except in phase II, where a larger difference was observed; the average WP of the three fields (1.14 kg m-3) was higher than that in the majority of the previous studies, which is a strong indicator of the efficient use of water in the studied soybean fields. The study showed that EEFlux, an innovative and free tool for access spatiotemporal variability of ETa and Kc at global scale is very efficient to estimate the ETa and Kc on different growth stages of soybean crop.


Assuntos
Irrigação Agrícola/métodos , Produção Agrícola/métodos , Produtos Agrícolas/fisiologia , Software , Soja/fisiologia , Clima , Produtos Agrícolas/crescimento & desenvolvimento , Modelos Estatísticos , Transpiração Vegetal , Soja/crescimento & desenvolvimento , Análise Espaço-Temporal
19.
Proc Natl Acad Sci U S A ; 117(31): 18385-18392, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32690686

RESUMO

Transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) can suppress pests and reduce insecticide sprays, but their efficacy is reduced when pests evolve resistance. Although farmers plant refuges of non-Bt host plants to delay pest resistance, this tactic has not been sufficient against the western corn rootworm, Diabrotica virgifera virgifera In the United States, some populations of this devastating pest have rapidly evolved practical resistance to Cry3 toxins and Cry34/35Ab, the only Bt toxins in commercially available corn that kill rootworms. Here, we analyzed data from 2011 to 2016 on Bt corn fields producing Cry3Bb alone that were severely damaged by this pest in 25 crop-reporting districts of Illinois, Iowa, and Minnesota. The annual mean frequency of these problem fields was 29 fields (range 7 to 70) per million acres of Cry3Bb corn in 2011 to 2013, with a cost of $163 to $227 per damaged acre. The frequency of problem fields declined by 92% in 2014 to 2016 relative to 2011 to 2013 and was negatively associated with rotation of corn with soybean. The effectiveness of corn rotation for mitigating Bt resistance problems did not differ significantly between crop-reporting districts with versus without prevalent rotation-resistant rootworm populations. In some analyses, the frequency of problem fields was positively associated with planting of Cry3 corn and negatively associated with planting of Bt corn producing both a Cry3 toxin and Cry34/35Ab. The results highlight the central role of crop rotation for mitigating impacts of D. v. virgifera resistance to Bt corn.


Assuntos
Besouros/fisiologia , Produção Agrícola/métodos , Endotoxinas/farmacologia , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/imunologia , Zea mays/imunologia , Animais , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Besouros/efeitos dos fármacos , Produção Agrícola/economia , Endotoxinas/genética , Endotoxinas/metabolismo , Resistência a Inseticidas , Iowa , Controle Biológico de Vetores/economia , Doenças das Plantas/economia , Doenças das Plantas/imunologia , Doenças das Plantas/prevenção & controle , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Soja/crescimento & desenvolvimento , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Zea mays/parasitologia
20.
Proc Natl Acad Sci U S A ; 117(32): 19131-19135, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32719119

RESUMO

Scaling current cereal production to a growing global population will be a challenge. Wheat supplies approximately one-fifth of the calories and protein for human diets. Vertical farming is a possible promising option for increasing future wheat production. Here we show that wheat grown on a single hectare of land in a 10-layer indoor vertical facility could produce from 700 ± 40 t/ha (measured) to a maximum of 1,940 ± 230 t/ha (estimated) of grain annually under optimized temperature, intensive artificial light, high CO2 levels, and a maximum attainable harvest index. Such yields would be 220 to 600 times the current world average annual wheat yield of 3.2 t/ha. Independent of climate, season, and region, indoor wheat farming could be environmentally superior, as less land area is needed along with reuse of most water, minimal use of pesticides and herbicides, and no nutrient losses. Although it is unlikely that indoor wheat farming will be economically competitive with current market prices in the near future, it could play an essential role in hedging against future climate or other unexpected disruptions to the food system. Nevertheless, maximum production potential remains to be confirmed experimentally, and further technological innovations are needed to reduce capital and energy costs in such facilities.


Assuntos
Produção Agrícola/métodos , Triticum/crescimento & desenvolvimento , Clima , Produção Agrícola/economia , Produção Agrícola/instrumentação , Ambiente Controlado , Estações do Ano , Temperatura
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