Soil sampling can help producers gain more accurate knowledge about soil nutrient properties and field-level characteristics. This information aids in the placement and timing of fertilizer application. Optimal input application may lower variable costs, increase economic returns, and moderate off-site environmental impacts of farming. Yet producer decisions to incorporate soil information into management practices and perceptions about the value of soil test information over time depends on a wide range of economic, social, and producer characteristics. Studies examining the value of soil information for optimal nutrient management may help inform producers considering adopting these technologies about the potential benefits of soil testing. This thesis provides two studies examining (1) the factors associated with the adoption of precision soil sampling and the length of time this information is perceived useful by cotton producers, and (2) the value of soil test information with regards to optimal potassium fertilizer management in cotton production over multiple growing seasons. Perceptions about the usefulness of soil test information over time depend on a variety of factors directly or indirectly related to input management. In the first study, the adoption and frequency of soil testing is examined as a function of off-farm, farm business, information sources, and operator characteristics using a Poisson hurdle regression model. Analyzing data from a survey of cotton farmers in 12 Southern states, the length of time producers perceived soil test information to be useful were influenced by farmer experience, land tenure, and the use of other information gathering technologies such as Greenseeker® and electro conductivity. In the second study, optimal potassium (K) management with information about fertilizer carryover was analyzed using a dynamic programming model. Monte Carlo simulation results suggest the information site-specific technologies provides with respect to residual fertilizer carryover effects of K are greatest when a producer is able to identify the magnitude of soil carryover capacity and incorporate this information to manage K. The information obtained from this research may provide insight for cotton producers, agribusiness firms, and agricultural service providers about the perception and potential benefits of soil sampling information to manage inputs in cotton production.

No description available.

Tasks: 1. To determine a soil sampling method most suitable for pH tests in soils on flat, rolling and hilly relief using regular grid sampling, soil database (Dirv_DB10LT) and soil agrochemical properties database (DirvAgroch_DB10LT). 2. To investigate the suitability of geostatistical methods for spatial distribution of pH data using different soil sampling methods. 3. To determine an impact of different soil sampling methods on spatial distribution of areas to be limed and on the needed amount of lime. Propositions to be defended: 1. Soil sampling plots for detailed pH tests should be shaped using soil database (Dirv_DB10LT) and soil agrochemical properties database (DirvAgroch_DB10LT); in case of high variability of pH values soil sampling plots should be smaller and in case of lower variability of pH values – larger. 2. Interpolation of pH data using IDW, Simple Kriging and Simple Cokriging methods results in decreased share of determined areas of conditionally acid soils when compared to that obtained using not interpolated pH data. 3. The needed amount of lime depends on soil sampling method. Larger needed amount of lime is calculated when soil samples are collected using databases (Dirv_DB10LT) and (DirvAgroch_DB10LT). / Uždaviniai: 1. Nustatyti dirvoţemio pH tyrimams tinkamiausią ėminių paėmimo metodą lyguminio, banguoto ir kalvoto reljefo plotuose, taikant taisyklingą tinklelį, dirvoţemio (Dirv_DB10LT) ir agrocheminių savybių (DirvAgroch_DB10LT) duomenų bazes. 2. Ištirti geostatistinių metodų tinkamumą pH duomenų erdviniam pasiskirstymui, taikant skirtingus ėminių paėmimo metodus. 3. Nustatyti ėminių paėmimo metodų įtaką kalkintinų plotų erdviniam pasiskirstymui ir kalkių reikmei. 32 Ginami disertacijos teiginiai: 1. Išsamiam dirvoţemio pH tyrimui ėminio paėmimo laukelius tikslinga formuoti naudojant dirvoţemių (Dirv_DB10LT) ir agrocheminių savybių (DirvAgroch_DB10LT) duomenų bazes, esant dideliam pH įvairavimui, dirvoţemio ėminius reikėtų imti tankiau, kai įvairavimas maţesnis – rečiau. 2. Dirvoţemio pH duomenis interpoliuojant IDW, paprastojo krigingo ir paprastojo kokrigingo metodais, sąlygiškai rūgščių plotų gaunama maţiau, palyginti su neinterpoliuotais. 3. Priklausomai nuo dirvoţemio ėminio paėmimo metodo, apskaičiuojama skirtinga kalkinių trąšų reikmė, ji didesnė plotuose, kuriuose dirvoţemio ėminiai imami naudojantis (Dirv_DB10LT) ir (DirvAgroch_DB10LT) duomenų bazėmis.

In the recent past precision farming has become increasingly popular amongfarmers. However, little has been done to study the business aspect of precision farming,with most research focusing on the production side. This purpose of this thesis is tostudy the feasibility of successfully opening and operating a precision farming firm inKentucky. To determine the feasibility of such a venture a computer model was createdand a producer survey was designed and distributed to farmers in Western and CentralKentucky.The purpose of the computer model was to determine the factors that wouldinfluence the successful operation of a precision farming firm including number of acresserviced per year, pricing of services, the cost of capital to borrow money, and manyother factors. A break-even analysis was performed to determine what kind of annualincreases in business would be required, what price range services should be in, and atwhat interest rate money could be borrowed and a simulated precision farming firm couldstill operate successfully.The producer survey was mailed to 336 farmers in Western and Central Kentuckybecause of their geographical locations and the type of crops that are grown there. Thesurvey response rate was 20 percent and of the 66 surveys that were returned 59 wereappropriate and useful for research. After compiling the results of the surveys,regressions were run to determine any correlation between dependent and independentvariables that affect the adoption rate of precision farming techniques. The results foundthat a negative correlation exists between age adoption rates of precision farming and thata positive correlation exists between farm size and adoption rates of precision farming.After conducting the research, it is believed that given the right economicconditions and management a precision farming firm is very capable of thriving inKentucky. However, the workforce must be very motivated and capable of constantlyrecruiting new clients to adopt precision farming.

No description available.

Considerando a grande importância do seqüestro de carbono (C) nos solos florestais, observa-se pequena quantidade de projetos de MDL que incluem esse compartimento como agente da mitigação do aquecimento global. Isso ocorre pelo fato da quantificação dos estoques de C do solo representar maiores desafios se comparada aos demais componentes dos ecossistemas florestais. Sabendo-se das dificuldades econômicas e ambientais envolvidas na adoção desse tipo projeto e da importância das florestas na mitigação da mudança do clima, o objetivo desse trabalho foi avaliar o desempenho de metodologias para a obtenção do estoque de C do solo em duas áreas de reflorestamento e suas respectivas linhas de base (usos do solo anteriores aos plantios, i.e. pastagens e vegetações nativa), como base para diminuir a relação custo-benefício de projetos de MDL. Para alcançar o objetivo principal, a presente pesquisa foi composta das seguintes etapas: (i) estudo da variabilidade espacial do C do solo em uma área de reflorestamento com espécies nativas, estabelecida em Cotriguaçú/MT (Área I) e em uma cronossequência de plantio de eucalipto, localizada em Avaré/SP (Área II); (ii) determinação do tamanho da parcela e do nº ideal de amostras a partir da dependência espacial do C nos reflorestamentos; (iii) estimativa dos teores de C e densidades do solo (Ds) pela Espectroscopia de Reflectância no Infravermelho Próximo (NIRS) e Médio (MIRS), visando a redução dos custos analíticos sem prejuízo da qualidade dos resultados; e (iv) cálculo dos estoques de C do solo nas áreas e estimativa do balanço de carbono do projeto de MDL conduzido na Área II, utilizando a ferramenta EX-ACT (Ex-Ante Carbon Balance Tool). Os resultados obtidos confirmaram a existência de importante variabilidade espacial do C do solo nas áreas e dependência espacial forte em todos os sistemas de manejo estudados. A análise do número ideal de amostras de solo indicou que a coleta de cinco pontos por parcela é tão precisa quanto uma amostragem com mais pontos. O tamanho ideal das parcelas variou de 361-841 m2 nos plantios da Área I e de 900-3721 m2 nos plantios da Área II. O desempenho dos métodos NIRS e MIRS na estimativa do teor de C dos solos foi bastante satisfatório, principalmente quando os modelos testados foram calibrados com quantidades entre 5-10% do conjunto de dados total. Os resultados da estimativa da Ds foram um pouco inferiores aos do C. Os estoques de C do solo obtidos na Área I foram superiores aos da Área II. Considerando apenas o solo, é possível afirmar que o potencial de geração de créditos de C é maior no reflorestamento com espécies nativas sob solo argiloso do que no reflorestamento com eucalipto em solo arenoso. O balanço de C do projeto conduzido na Área I indicou o seqüestro de quase três milhões de toneladas de CO2eq em 40 anos. Espera-se que este estudo contribua para o aumento da inclusão do solo em projetos de MDL, uma vez comprovada a possibilidade de redução dos custos associados à obtenção e determinação dos estoques de C nesse compartimento / Considering the great importance of carbon sequestration (C) in forest soils, there are few CDM projects that include this compartment as an agent of global warming mitigation. This occurs because the quantification of soil C stocks represents a bigger challenge when compared to other components of forest ecosystems. Considering the economic difficulties and environmental issues involved in adopting this type of project and the importance of forests in mitigating climate change, the objective of this study was to evaluate the performance of methods for obtaining soil C stocks in two forestry areas and their respective baselines (land use prior to planting, i.e. pastures and native vegetation) as a basis for reducing the cost-benefit ratio of CDM projects. To achieve the main objective, this research was composed of the following steps: (i) estimating the spatial variability of soil C in an area reforested with native species, established in Cotriguaçú, MT (Area I) and a Eucalyptus chronosequence, located in Avaré, SP (Area II), (ii) determining the optimal amount of soil samples and the plot size from the soil C spatial dependence range in the reforestation areas, (iii) estimating soil C content and bulk density (BD) by Near and Mid Infrared Reflectance Spectroscopy (NIRS and MIRS, respectively) to reduce analytical costs without affecting the quality of the results, and (iv) calculating soil C stocks in both areas and estimating the carbon balance of a CDM Project conducted in Area II, using EX-ACT (\"Ex-Ante Carbon Balance Tool\"). The results confirmed the existence of significant soil C spatial variability in both areas and a strong spatial dependence at all plots. The analysis of the optimal number of soil samples indicated that the sampling procedure with five points per plot is as accurate as intensive sampling. The optimum size of plots ranged from 361-841 m2 at Area I plantations and from 900-3721 m2 at Area II. The performance of MIRS and NIRS to estimate the soil carbon content was very satisfactory, especially when the models were calibrated with amounts between 5-10% of the total data set. The estimations of BD were slightly less precise than those of soil C content. The soil C stocks obtained at Area I were higher than Area II. Considering only the soil compartment, it is clear that the potential for C credit generation in a reforestation with native species on a clayey soil is higher than in a reforestation with eucalyptus on a sandy soil. The C balance of the CDM project conducted in Area I is expected to sequester almost three million tones of CO2 eq in 40 years. We hope this study contributes to the increased inclusion of soil in CDM projects, by confirming the feasibility of reducing the costs associated with both sampling and analytical procedures

The fundamental step of a fertility assessment program is soil sampling, in which the number of points collected should be sufficient to detect the spatial variability of soil attributes. However, due to soil heterogeneity, there is no agreement on the number of subsamples needed to estimate the soil properties values, with sufficient precision and representativeness. Therefore, the objective of this work is to determine the spatial variability of soil chemical attributes in areas under no-tillage system with fertilization in the line and the haul, and to establish the minimum number of subsamples necessary to form a representative composite sample within certain precision limits . The work was carried out in two properties, located in the municipality of Palmeira das Missões - RS. Soil sampling was performed at points of intersection in a square mesh of 49 points, spaced at regular intervals of 5 x 5m. The samples were collected in two different management systems, one area under no-tillage with fertilization in the line and the other with fertilization in the haul. In both areas, the soil was collected with a shovel in the 0-0.15 m depth. The evaluated attributes were: pH, P, K, Ca, Mg, H + Al, CTC, V% and MO. The data were submitted to the exploratory analysis, and the statistical parameters determined were: mean, median, minimum, maximum, standard deviation, coefficients of variation, asymmetry and kurtosis. The minimum number of subsamples required to form a representative composite sample was also determined. The ideal number of subsamples, to form a representative composite sample, will vary according to the fertilization system, error probability and error in relation to the mean. Among the precision limits studied, it was recommended to work both in the system with fertilization in the haul and in the line with probability of error α of 0.05 and error in relation to the average of 20%. Considering this same error, it is suggested to collect at least 11 to 12 subsamples per sample point, to form a representative composite sample with a cutting blade. / A etapa fundamental de um programa de avaliação da fertilidade é a amostragem do solo, na qual o número de pontos coletados deve ser suficiente para detectar a variabilidade espacial dos atributos do solo. Entretanto, em função da heterogeneidade dos solos não há uma concordância quanto ao número de subamostras necessárias para se estimar os valores das propriedades do solo, com suficiente precisão e representatividade. Portanto, o objetivo desse trabalho é determinar a variabilidade espacial dos atributos químicos do solo em áreas sob sistema plantio direto com adubação na linha e a lanço, e estabelecer o número mínimo de subamostras necessárias para formar uma amostra composta representativa dentro de determinados limites de precisão. O trabalho foi realizado em duas propriedades, localizadas no município de Palmeira das Missões – RS. A amostragem de solo foi realizada nos pontos de interseção em uma malha quadrada de 49 pontos, espaçados em intervalos regulares de 5x5 m. As amostras foram coletadas em dois sistemas de manejo diferentes, sendo uma área conduzida sob sistema plantio direto com adubação na linha e a outra com adubação a lanço. Em ambas as áreas o solo foi coletado com pá-de-corte na profundidade de 0-0,15 m. Os atributos avaliados foram: pH, P, K, Ca, Mg, H+Al, CTC, V% e MO. Os dados foram submetidos à análise exploratória, sendo que os parâmetros estatísticos determinados foram: média, mediana, mínimo, máximo, desvio padrão, coeficientes de variação, de assimetria e de curtose. Determinou-se também, o número mínimo de subamostras, necessárias para formar uma amostra composta representativa. O número ideal de subamostras, para formar uma amostra composta representativa, irá variar conforme o sistema de adubação, probabilidade de erro e o erro em relação à média. Dentre os limites de precisão estudados, recomendasse trabalhar tanto no sistema com adubação a lanço e na linha com probabilidade de erro α de 0,05 e erro em relação à média de 20%. Considerando esse mesmo erro, sugere-se coletar pelos menos 11 a 12 subamostras por ponto amostral, para formar uma amostra composta representativa com pá de corte.

Considerando a grande importância do seqüestro de carbono (C) nos solos florestais, observa-se pequena quantidade de projetos de MDL que incluem esse compartimento como agente da mitigação do aquecimento global. Isso ocorre pelo fato da quantificação dos estoques de C do solo representar maiores desafios se comparada aos demais componentes dos ecossistemas florestais. Sabendo-se das dificuldades econômicas e ambientais envolvidas na adoção desse tipo projeto e da importância das florestas na mitigação da mudança do clima, o objetivo desse trabalho foi avaliar o desempenho de metodologias para a obtenção do estoque de C do solo em duas áreas de reflorestamento e suas respectivas linhas de base (usos do solo anteriores aos plantios, i.e. pastagens e vegetações nativa), como base para diminuir a relação custo-benefício de projetos de MDL. Para alcançar o objetivo principal, a presente pesquisa foi composta das seguintes etapas: (i) estudo da variabilidade espacial do C do solo em uma área de reflorestamento com espécies nativas, estabelecida em Cotriguaçú/MT (Área I) e em uma cronossequência de plantio de eucalipto, localizada em Avaré/SP (Área II); (ii) determinação do tamanho da parcela e do nº ideal de amostras a partir da dependência espacial do C nos reflorestamentos; (iii) estimativa dos teores de C e densidades do solo (Ds) pela Espectroscopia de Reflectância no Infravermelho Próximo (NIRS) e Médio (MIRS), visando a redução dos custos analíticos sem prejuízo da qualidade dos resultados; e (iv) cálculo dos estoques de C do solo nas áreas e estimativa do balanço de carbono do projeto de MDL conduzido na Área II, utilizando a ferramenta EX-ACT (Ex-Ante Carbon Balance Tool). Os resultados obtidos confirmaram a existência de importante variabilidade espacial do C do solo nas áreas e dependência espacial forte em todos os sistemas de manejo estudados. A análise do número ideal de amostras de solo indicou que a coleta de cinco pontos por parcela é tão precisa quanto uma amostragem com mais pontos. O tamanho ideal das parcelas variou de 361-841 m2 nos plantios da Área I e de 900-3721 m2 nos plantios da Área II. O desempenho dos métodos NIRS e MIRS na estimativa do teor de C dos solos foi bastante satisfatório, principalmente quando os modelos testados foram calibrados com quantidades entre 5-10% do conjunto de dados total. Os resultados da estimativa da Ds foram um pouco inferiores aos do C. Os estoques de C do solo obtidos na Área I foram superiores aos da Área II. Considerando apenas o solo, é possível afirmar que o potencial de geração de créditos de C é maior no reflorestamento com espécies nativas sob solo argiloso do que no reflorestamento com eucalipto em solo arenoso. O balanço de C do projeto conduzido na Área I indicou o seqüestro de quase três milhões de toneladas de CO2eq em 40 anos. Espera-se que este estudo contribua para o aumento da inclusão do solo em projetos de MDL, uma vez comprovada a possibilidade de redução dos custos associados à obtenção e determinação dos estoques de C nesse compartimento / Considering the great importance of carbon sequestration (C) in forest soils, there are few CDM projects that include this compartment as an agent of global warming mitigation. This occurs because the quantification of soil C stocks represents a bigger challenge when compared to other components of forest ecosystems. Considering the economic difficulties and environmental issues involved in adopting this type of project and the importance of forests in mitigating climate change, the objective of this study was to evaluate the performance of methods for obtaining soil C stocks in two forestry areas and their respective baselines (land use prior to planting, i.e. pastures and native vegetation) as a basis for reducing the cost-benefit ratio of CDM projects. To achieve the main objective, this research was composed of the following steps: (i) estimating the spatial variability of soil C in an area reforested with native species, established in Cotriguaçú, MT (Area I) and a Eucalyptus chronosequence, located in Avaré, SP (Area II), (ii) determining the optimal amount of soil samples and the plot size from the soil C spatial dependence range in the reforestation areas, (iii) estimating soil C content and bulk density (BD) by Near and Mid Infrared Reflectance Spectroscopy (NIRS and MIRS, respectively) to reduce analytical costs without affecting the quality of the results, and (iv) calculating soil C stocks in both areas and estimating the carbon balance of a CDM Project conducted in Area II, using EX-ACT (\"Ex-Ante Carbon Balance Tool\"). The results confirmed the existence of significant soil C spatial variability in both areas and a strong spatial dependence at all plots. The analysis of the optimal number of soil samples indicated that the sampling procedure with five points per plot is as accurate as intensive sampling. The optimum size of plots ranged from 361-841 m2 at Area I plantations and from 900-3721 m2 at Area II. The performance of MIRS and NIRS to estimate the soil carbon content was very satisfactory, especially when the models were calibrated with amounts between 5-10% of the total data set. The estimations of BD were slightly less precise than those of soil C content. The soil C stocks obtained at Area I were higher than Area II. Considering only the soil compartment, it is clear that the potential for C credit generation in a reforestation with native species on a clayey soil is higher than in a reforestation with eucalyptus on a sandy soil. The C balance of the CDM project conducted in Area I is expected to sequester almost three million tones of CO2 eq in 40 years. We hope this study contributes to the increased inclusion of soil in CDM projects, by confirming the feasibility of reducing the costs associated with both sampling and analytical procedures

Sample grid s are essential when we want to represent the variation in chemical and physical properties of the soil, being essential to know its features. In this way, this study aimed to relate the efficiency and practicality of using soil sampling knits of rectangular and hexagonal type in a farm located countryside Ivorá- RS. In order to get features that help the researcher and producer in choosing the appropriate mesh to represent and diagnose their crops by means of fertility maps and application. The methodological procedures consisted of structuring the rectangular and hexagonal sampling knits of 1 ha in the CR Campeiro 7, without user interference in the point s distribution. Soil samples were collected in June 2015. So, after analysis of the spatial distribution of points in the area for each of the cases the fertility maps and application were structured. Among the main results, it is noted that both knits can represent similarly the trends that the soil presents nevertheless, the rectangular grid, due to a higher number of points, can represent the variability more expressively, but was found that when there is a change in the position and number of sampling points in a crop, the representations of the maps have differences, which at first, analyzing only the fertility maps, these differences seem small, but when structured a map of application, this difference becomes significant as it will result in greater or lesser purchase of inputs. It is emphasized that each mesh has characteristics that will inevitably vary from crop to crop, and a sampling grid should be, always, planned and adjusted according to each case, combining the knowledge of the producer and additional data available to define the same. / As malhas de amostragem são fundamentais quando desejamos representar a variação de atributos químicos e físicos do solo, sendo imprescindível conhecer suas características. Desta forma, este trabalho teve como objetivo relacionar a eficiência e a praticidade da utilização das malhas de amostragem de solo do tipo retangular e hexagonal, em uma lavoura localizada no município de Ivorá- RS. Com o propósito de buscar características que auxiliem o pesquisador e o produtor na escolha da malha adequada para representar e diagnosticar suas lavouras, através de mapas de fertilidade e de aplicação. Os procedimentos metodológicos consistiram em estruturar as malhas de amostragem retangular e hexagonal de 1 ha no Sistema CR Campeiro 7, sem a interferência do usuário na distribuição dos pontos. As respectivas coletas de solo ocorreram no mês de junho de 2015. Assim, após a análise da distribuição espacial dos pontos na área para cada um dos casos e estruturados os mapas de fertilidade e aplicação. Entre os principais resultados encontrados, salienta-se que ambas as malhas conseguem representar de forma similar as tendências que o solo apresenta, no entanto, a malha retangular, por apresentar maior número de pontos, consegue representar a variabilidade de forma mais expressiva, mas nota-se que quando há uma alteração na posição e no número de pontos amostrais em uma lavoura, as representações dos mapas apresentam diferenças, que num primeiro momento, analisando somente os mapas de fertilidade, essas diferenças parecem ser pequenas, mas quando estruturado um mapa de aplicação, essa diferença passa a ser significativa, pois resultará em maior ou menor aquisição de insumos. Salienta-se que cada malha apresenta características que, inevitavelmente, variam de lavoura para lavoura, e uma malha de amostragem deve ser, sempre, planejada e ajustada conforme cada caso, aliando o conhecimento do produtor e dados adicionais disponíveis para definição da mesma.

Separate field studies were started in fall 2005, which continued through fall 2007, to investigate the effect of different levels of European corn borer tunneling on yield in corn grown for grain and to predict spring infestation levels of early season soil insects, specifically white grubs (Coleoptera: Scarabaeidae) and wireworms (Coleoptera: Elateridae) in cornfields. In the first study, model variables included corn growth stage and larvae per plant. In both years of this study, larvae per plant had a significant effect on grain yield. Grain yield was reduced by 13.1 and 3.65% in plants infested with four larvae per plant in 2006 and 2007, respectively. For 2006, linear regression models provided average percent yield loss per larva per plant at 4.1, 6.8, and 1.8% during late vegetative (V12), early silking (R1), and blister (R2) growth stages, respectively. Economic injury levels (EILs) were calculated based on average percent yield reductions across each growth stage and year. In the second study, no significant differences were detected in both fall and spring between two sampling methods after correcting for differences in sampling volume. Strong correlations were observed between fall and spring grub densities in both years. In 2006, fields with grub densities above the spring nominal threshold had significantly greater stand and yield in the Poncho 1250 (1.25 mg clothianidin / kernel) treatment when compared to the Poncho 250 (0.25 mg clothianidin / kernel) and untreated plots. This information was used to develop fall EILs and economic thresholds for white grubs. / Master of Science in Life Sciences