No description available.

The unique characteristics of agricultural contamination of groundwater requires an innovative solution, such as the voluntary use of low-input agriculture (LIA) practices. This study was conducted to identify potential barriers to LIA adoption, analyze the effectiveness of agriculture and natural resource policies designed to remove the barriers to LIA adoption, and to determine the effectiveness of LIA practices in reducing the amount of chemicals released into the environment. A survey of Richmond County, Virginia farming operations and attitudes identified current practices, potential LIA practices for the Northern Neck region of Virginia, and perceived barriers to LIA adoption. A 15 year nonlinear mathematical programming model was used to determine optimal farming practices, among 34 low-input and conventional practices, under various agronomic and policy scenarios. Two non-point simulation models, CREAMS and GLEAMS, were used to estimate the nitrogen and chemical loadings of runoff, groundwater, and sediment; and the soil erosion from each of these scenarios. The model shows that yields, labor requirements, and variable costs, individually have a weak influence on the adoption of low-chemical and organic production activities. The price of the organic nitrogen source, poultry litter, was strongly related to the use of LIA practices. The most cost effective policy for reducing Aatrex (atrazine) contributions to groundwater was a one-third reduction in surface application of Aatrex. However, there were many tradeoffs between chemical, nitrogen, and soil contributions to runoff, percolation, and sediment. The only policies which reduced all of these factors were land retirement policies. The tax level required to promote the use of a LIA practice was too high to be politically feasible, and the use of green-manure crops would require a 100 percent annual subsidy of those crops. A proposed base flexibility program caused more intensive use of conventional chemicals because of the limited number of eligible crops. Low-input agriculture has promised reductions in chemical contamination of groundwater and runoff. This study’s results showed that although that is indeed the case, there are tradeoffs between reduced chemical contamination and nitrogen and soil losses which should be considered when examining the cost effectiveness of using LIA practices as a groundwater protection strategy. / Ph. D.

An advisory program to determine the timing of fungicide application for control of early leafspot of peanut, caused by Cercospora arachidicola, was developed based on growth responses of the pathogen to specific environmental conditions. The advisory program (89-ADV) assigned time-duration values to conditions conducive for infection (TDVi). Cumulative TDVi levels were used to determine when fungicide applications were needed. Various spray thresholds (TDVi=48, 72, 96, 120) of the 89-ADV program were compared to a 14-day spray schedule and an advisory program that was released to growers in 1981 (81-ADV). Leafspot incidence, area under the disease progress curve (AUDPC), spray number, yield and value were used to evaluate the performance of spray programs. Preliminary trials used Florigiant peanut and the fungicide chlorothalonil (1.26 kg/ha). The 89-ADV program with TDVi=48 performed exceptionally well for three consecutive years in field tests and in simulated disease environments reconstructed from historical weather data. Benefits of this program compared to the 81-ADV program included significant improvement of leafspot control, and improved crop yield and value. Based on performance, the 89-ADV program was delivered to growers as the on-line peanut leafspot advisory in 1989. Subsequent evaluations of the 89-ADV program included cultivars and fungicides in large multi-factorial experiments. Three classes of cultivars were identified: class I or highly susceptible, Florigiant and NC 9; class II or moderately susceptible, NC 7 and NC-V11; and class III or moderately resistant, NC 6. The efficiency of fungicide sprays was improved through effective leafspot control with about three fewer sprays per season than the 14-day spray schedule when chlorothalonil at 1.26 kg/ha, diniconazole at 140 g/ha or terbutrazole at 126 g/ha was applied on class I cultivars according to the TDVi=48 threshold of the 89-ADV program. The same efficiency was achieved when chlorothalonil or terbutrazole was applied on class II cultivars according to the TDVi=96. Cupric hydroxide at 1.79 kg/ha plus sulfur at 1.04 kg/ha or terbutrazole at 126 kg/ha with TDVi=96 as well as chlorothalonil at 1.26 kg/ha with TDVi=120 resulted in efficient control of disease on the class III cultivar. The spray adjuvant SoyOil 937® at 0.5% of spray volume consistently improved the performance of chlorothalonil, and allowed a reduction of application rate from 1.26 to 0.95 kg/ha without sacrificing disease control. The integrated use of cultivar resistance, fungicide, spray adjuvant, and TDVi thresholds of the 89-ADV program contributed to a reduction of fungicide input and improved disease control. / Ph. D.

Orientador: Dagoberto Martins / Banca: Luciano Soares de Souza / Banca: Robinson Luiz Campos Machado Pitelli / Resumo: Os herbicidas devem apresentar seletividade às culturas agrícolas, ou seja, controlar as plantas daninhas sem comprometer o desenvolvimento e a produtividade da cultura. O objetivo deste trabalho foi avaliar a seletividade de herbicidas aplicados em pré-emergência das plantas daninhas e pré-plantio de três cultivares de cana-de-açúcar plantadas pelo sistema de mudas pré-brotadas (MPB). O experimento foi desenvolvido na Usina São Martinho próximo ao município de Pradópolis (SP), sob condições naturais de clima, no período de setembro a novembro de 2013. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições. Os tratamentos foram distribuídos em esquema fatorial (3x8), sendo o fator A composto por três cultivares CTC14, CTC7 e RB966928; e o fator B por sete herbicidas S-metolachlor (2640 g ha-1); clomazone (1000 g ha-1); sulfentrazone (800 g ha-1); diclosulam (200 g ha-1); metribuzin (1920 g ha-1); diuron + hexazinone (1170 + 330 g ha-1); S-metolachlor + sulfentrazone (2640 + 800 g ha-1) mais uma testemunha sem aplicação de herbicidas. Foram avaliados os sintomas visuais de fitointoxicação e a condutância estomática (gs) aos 14, 28, 35, 42, 49, 56 e 63 dias após aplicação (DAA), a altura e o número de perfilhos das cultivares aos 14, 35, 49 e 63 DAA, a massa seca da parte aérea (MSPA) e a massa seca do sistema radicular (MSSR) aos 63 DAA. Nas condições em que o experimento foi conduzido, os herbicidas S-metolachlor, clomazone, metribuzin, diuron + hexazinone e S-metolachlor + sulfentrazone, foram seletivos as mudas pré-brotadas de cana-de-açúcar. O herbicida diclosulam foi o menos seletivo, seguido do sulfentrazone. A CTC14 apresentou-se visualmente menos tolerante aos herbicidas ... / Abstract: The herbicides must provide selectivity to agricultural crops, moreover, they must control weeds without compromising crop's productivity. The aim was to evaluate the selectivity of herbicides applied on pre-emergence of weeds and pre-planting of three sugarcane cultivars planted by pre-sprouted seedlings (MPB) system. The experiment was carried out in the São Martinho Sugar Mill, in the municipality of Pradópolis (SP), under natural climatic conditions from September to November of 2013. The experimental design was a completely randomized with four replications. The treatments were arranged in a factorial (3x8), where the factor A consisted of three cultivars CTC14, CTC7 and RB966928; and the factor B consisted of seven herbicides: S-metolachlor (2640 g ha-1); clomazone (1000 g ha-1); sulfentrazone (800 g ha-1); diclosulam (200 g ha-1); metribuzin (1920 g ha-1); diuron + hexazinone (1170 + 330 g ha-1); S-metolachlor + sulfentrazone (2640 + 800 g ha-1) and a control without herbicide application. Visual symptoms of intoxication and stomatal conductance (gs) were evaluated at 14, 28, 35, 42, 49, 56 and 63 days after application (DAA); plant height and number of tillers at 14, 35, 49 and 63 DAA; the dry weight of shoot (DWS) and the dry weight of root (DWR) at 63 DAA. In the conditions which the experiment was conducted, the herbicides S-metolachlor, clomazone, metribuzin, diuron + hexazinone and S-metolachlor + sulfentrazone were selective to pre-sprouted seedlings of sugarcane. The herbicide diclosulam was the least selective one, followed by sulfentrazone. The CTC14 cultivar presented the lowest tolerance to the herbicides diclosulam and sulfentrazone / Mestre

Public health was once synonymous with environmental health. However, as living conditions improved the two fields diverged. Environmental factors are again re-emerging as hazards human health. Increasing global reliance on agricultural and veterinary chemicals (AgVets) over recent decades has is now a serious public health concern. Evidence of their toxicity has prompted international efforts to minimize, monitor and manage exposure risks. Direct involvement of the primary health care workforce is seen as critical to this process, yet little data exists on the health burden on Australian rural communities imposed by these chemicals. The study presented here attempts to explore the impact of these chemicals on two rural communities in Victoria, and ascertain the how the existing primary heath care system responds to AgVet exposure issues. Health determinants are complex, and inter-related, and the client �provider interface is not an entity acting in isolation from other frameworks. The provider-client service relationship has evolved against a background of legislation and provider training. Many external factors also impinge, such as the structure and focus of the health sector, and Australia�s systematic approach to environmental and chemical management. Examination of this underlying infrastructure in Australia provided the background against which the issue of exposure to agricultural and veterinary chemicals was explored. A brief summary of international developments in this area served to provide insight as to what interventions may be introduced to address the issue of chemical exposure. A CATI (Computer Assisted Telephone Interview) survey of 1050 households sought the perspectives from two Victorian agricultural communities to gather self-reported AgVet exposure patterns and health data, and whether respondents perceived their health problems were linked to exposure. Respondents were also asked to comment on the primary health care service experiences from local providers, and which services they preferred to seek for health advice. Perspectives were then sought from all primary health care providers servicing these communities. Information was sought on their level of expertise in diagnosing, and managing exposure related illness, via face-to-face interviews, focus groups and paper surveys. The study revealed rural communities have a long history of hazardous exposure to toxic AgVets. Awareness of toxicity risks is growing, yet further scope exists to improve safe handling of chemicals. High levels of illnesses known be associated with AgVet exposure exist among rural populations. Many believe their own ill-health is linked to exposure, and express strong dissatisfaction with the apparent lack of environmental health expertise especially among their GPs. Health providers demonstrated limited understanding of the health impacts of AgVet exposure. The lack of environmental health expertise among the existing primary health care workforce means that health conditions associated with exposure to AgVets are not being identified, and the absence of health intelligence hampers health planning. In Australia, the health, environment and primary industries sectors function in effect, as distinct silos, with little cross-fertilisation. The United States has combined its agricultural chemical legislative authority to develop a focus on human health, establish direct links, and biomonitoring programs to protect human heath. The U.S. has also developed environmental health expertise at the primary health care level to address community needs as they arise. Strategies are required in Australia to connect the environment, chemical management and health portfolios, with respect to the emerging environmental issues of chemical exposure. There is a need also in Australia to inject environmental health capacity into the primary health care practice.

No description available.

Public health was once synonymous with environmental health. However, as living conditions improved the two fields diverged. Environmental factors are again re-emerging as hazards human health. Increasing global reliance on agricultural and veterinary chemicals (AgVets) over recent decades has is now a serious public health concern. Evidence of their toxicity has prompted international efforts to minimize, monitor and manage exposure risks. Direct involvement of the primary health care workforce is seen as critical to this process, yet little data exists on the health burden on Australian rural communities imposed by these chemicals. The study presented here attempts to explore the impact of these chemicals on two rural communities in Victoria, and ascertain the how the existing primary heath care system responds to AgVet exposure issues. Health determinants are complex, and inter-related, and the client �provider interface is not an entity acting in isolation from other frameworks. The provider-client service relationship has evolved against a background of legislation and provider training. Many external factors also impinge, such as the structure and focus of the health sector, and Australia�s systematic approach to environmental and chemical management. Examination of this underlying infrastructure in Australia provided the background against which the issue of exposure to agricultural and veterinary chemicals was explored. A brief summary of international developments in this area served to provide insight as to what interventions may be introduced to address the issue of chemical exposure. A CATI (Computer Assisted Telephone Interview) survey of 1050 households sought the perspectives from two Victorian agricultural communities to gather self-reported AgVet exposure patterns and health data, and whether respondents perceived their health problems were linked to exposure. Respondents were also asked to comment on the primary health care service experiences from local providers, and which services they preferred to seek for health advice. Perspectives were then sought from all primary health care providers servicing these communities. Information was sought on their level of expertise in diagnosing, and managing exposure related illness, via face-to-face interviews, focus groups and paper surveys. The study revealed rural communities have a long history of hazardous exposure to toxic AgVets. Awareness of toxicity risks is growing, yet further scope exists to improve safe handling of chemicals. High levels of illnesses known be associated with AgVet exposure exist among rural populations. Many believe their own ill-health is linked to exposure, and express strong dissatisfaction with the apparent lack of environmental health expertise especially among their GPs. Health providers demonstrated limited understanding of the health impacts of AgVet exposure. The lack of environmental health expertise among the existing primary health care workforce means that health conditions associated with exposure to AgVets are not being identified, and the absence of health intelligence hampers health planning. In Australia, the health, environment and primary industries sectors function in effect, as distinct silos, with little cross-fertilisation. The United States has combined its agricultural chemical legislative authority to develop a focus on human health, establish direct links, and biomonitoring programs to protect human heath. The U.S. has also developed environmental health expertise at the primary health care level to address community needs as they arise. Strategies are required in Australia to connect the environment, chemical management and health portfolios, with respect to the emerging environmental issues of chemical exposure. There is a need also in Australia to inject environmental health capacity into the primary health care practice.

Thesis (Ph.D.)--Mississippi State University. Department of Plant and Soil Sciences. / Title from title screen. Includes bibliographical references.

Made available in DSpace on 2015-04-09T12:28:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-11-26Bitstream added on 2015-04-09T12:47:50Z : No. of bitstreams: 1 000817850.pdf: 779106 bytes, checksum: b7fa11df71486c11610b2e153931a26a (MD5) / Os herbicidas devem apresentar seletividade às culturas agrícolas, ou seja, controlar as plantas daninhas sem comprometer o desenvolvimento e a produtividade da cultura. O objetivo deste trabalho foi avaliar a seletividade de herbicidas aplicados em pré-emergência das plantas daninhas e pré-plantio de três cultivares de cana-de-açúcar plantadas pelo sistema de mudas pré-brotadas (MPB). O experimento foi desenvolvido na Usina São Martinho próximo ao município de Pradópolis (SP), sob condições naturais de clima, no período de setembro a novembro de 2013. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições. Os tratamentos foram distribuídos em esquema fatorial (3x8), sendo o fator A composto por três cultivares CTC14, CTC7 e RB966928; e o fator B por sete herbicidas S-metolachlor (2640 g ha-1); clomazone (1000 g ha-1); sulfentrazone (800 g ha-1); diclosulam (200 g ha-1); metribuzin (1920 g ha-1); diuron + hexazinone (1170 + 330 g ha-1); S-metolachlor + sulfentrazone (2640 + 800 g ha-1) mais uma testemunha sem aplicação de herbicidas. Foram avaliados os sintomas visuais de fitointoxicação e a condutância estomática (gs) aos 14, 28, 35, 42, 49, 56 e 63 dias após aplicação (DAA), a altura e o número de perfilhos das cultivares aos 14, 35, 49 e 63 DAA, a massa seca da parte aérea (MSPA) e a massa seca do sistema radicular (MSSR) aos 63 DAA. Nas condições em que o experimento foi conduzido, os herbicidas S-metolachlor, clomazone, metribuzin, diuron + hexazinone e S-metolachlor + sulfentrazone, foram seletivos as mudas pré-brotadas de cana-de-açúcar. O herbicida diclosulam foi o menos seletivo, seguido do sulfentrazone. A CTC14 apresentou-se visualmente menos tolerante aos herbicidas ... / The herbicides must provide selectivity to agricultural crops, moreover, they must control weeds without compromising crop's productivity. The aim was to evaluate the selectivity of herbicides applied on pre-emergence of weeds and pre-planting of three sugarcane cultivars planted by pre-sprouted seedlings (MPB) system. The experiment was carried out in the São Martinho Sugar Mill, in the municipality of Pradópolis (SP), under natural climatic conditions from September to November of 2013. The experimental design was a completely randomized with four replications. The treatments were arranged in a factorial (3x8), where the factor A consisted of three cultivars CTC14, CTC7 and RB966928; and the factor B consisted of seven herbicides: S-metolachlor (2640 g ha-1); clomazone (1000 g ha-1); sulfentrazone (800 g ha-1); diclosulam (200 g ha-1); metribuzin (1920 g ha-1); diuron + hexazinone (1170 + 330 g ha-1); S-metolachlor + sulfentrazone (2640 + 800 g ha-1) and a control without herbicide application. Visual symptoms of intoxication and stomatal conductance (gs) were evaluated at 14, 28, 35, 42, 49, 56 and 63 days after application (DAA); plant height and number of tillers at 14, 35, 49 and 63 DAA; the dry weight of shoot (DWS) and the dry weight of root (DWR) at 63 DAA. In the conditions which the experiment was conducted, the herbicides S-metolachlor, clomazone, metribuzin, diuron + hexazinone and S-metolachlor + sulfentrazone were selective to pre-sprouted seedlings of sugarcane. The herbicide diclosulam was the least selective one, followed by sulfentrazone. The CTC14 cultivar presented the lowest tolerance to the herbicides diclosulam and sulfentrazone

A soja é uma das principais commodities produzidas no mundo. Entretanto, tem sua produtividade reduzida, significativamente, devido às doenças, dentre estas o mofo branco, causado pelo fungo Sclerotinia sclerotiorum, com expressiva severidade em regiões de clima ameno e úmido. O controle da doença, incluindo o uso de fungicidas, é pouco eficiente. Assim, o trabalho teve por objetivo avaliar a eficiência de herbicidas e adubos foliares à base de fosfito de potássio no manejo do mofo branco em soja, bem como a ação dos produtos, indução da síntese de fitoalexinas e das enzimas peroxidases e superóxido dismutase, assim como a ação direta dos agroquímicos sobre o patógeno. Para isso, avaliou-se a ação in vitro dos produtos químicos sobre o crescimento micelial do fungo e germinação de escleródios. A indução foi testada em laboratório por meio da avaliação da síntese de fitoalexinas em cotilédones de soja, e das enzimas POX e SOD, submetidas aos mesmos tratamentos de campo. O experimento de campo foi implantado em Coronel Domingos Soares - PR, safra 2012/2013, em área com infestação natural do fitopatógeno. O delineamento experimental foi de blocos ao acaso, com 4 repetições e 6 tratamentos: testemunha, lactofen (0,6 L ha-1 em V4), bentazon (1,5 L ha-1 em V4), fluazinam (1 L ha-1 em R1) e dois adubos foliares denominados fosfito A (30 p/p % de P2O5 e 20 p/p % de K2O) (3 L ha-1 em V4 + R1) e fosfito B (26 p/p % de P2O5 e 19 p/p % de K2O) (2 L ha-1 em V4 + R1). O fungicida foi o único produto que inibiu totalmente o desenvolvimento do fungo in vitro. Em laboratório, o bentazon alcançou os maiores índices de produção de fitoalexinas, enquanto os adubos foliares não as induziram. Ambos os herbicidas e o fosfito A tiveram potencial para aumentar a atividade da enzima POX. No experimento de campo os herbicidas bentazon e lactofen destacaram-se no controle do mofo branco, sendo de 60,5% e 52,3%, respectivamente, e o tratamento com fosfito A com um controle de 37,9%, superiores ao tratamento com fungicida. Em relação aos componentes de rendimento houve incrementos utilizando os herbicidas, entretanto, não diferiram estatisticamente da testemunha pelo teste de Duncan a 5%. / Soybean is one of the most important crops in the world. However, several times the yield is reduced due to diseases as the stem rot (white mold) caused by Sclerotinia sclerotiorum, which is a several fungal, mainly in areas with low temperatures and high moisture. The disease control, including the use of fungicides, is difficult. Thus, the objective of this study was to verify the effect of herbicides and foliar fertilizers with potassium phosphite on control of white mold soybean, determining the action of this agrochemicals about the phytoalexin, superoxide dismutase and peroxidase synthesis, and the direct action on the pathogen. For this, the in vitro effect of agrochemicals on the pathogen was evaluated. Also, the induction was tested in the laboratory by evaluation of phytoalexin synthesis in soybean cotyledons, and POX and SOD enzymes, subjected to the same treatment field. The field trials were conducted in Coronel Domingos Soares – PR, evaluations were made in 2012/2013 crop. A randomized-complete blocks design with 6 treatments and 4 replicates was used. The treatments were: lactofen (0,6 L ha-1 applied in V4), bentazon (1,5 L ha-1 in V4), fluazinam (1 L ha-1 in R1) and two foliar fertilizers called fosfito A (30 p/p % de P2O5 and 20 p/p % de K2O) (3 L ha-1 in V4 + R1) and fosfito B (26 p/p % de P2O5 and 19 p/p % de K2O) (2 L ha-1 in V4 + R1). . The fungicide was the only product that completely inhibited fungal growth in vitro. In the laboratory, the bentazon reached the highest levels of phytoalexin production, but the foliar fertilizers did not induce the production of the same. Both herbicides and phosphite A had the potential to elicit the production of peroxidase enzyme. In field experiments the herbicides bentazon and lactofen stood out in the control of white mold, being 60.5% and 52.3% respectively, and treatment with the fosfito A provided a control of 37.9%, being superior to the treatment with fungicide. Regarding the grain fields compounds had increase using the herbicides, but did not differed from the control by Duncan test at 5%.