Bioreactor landfills offer a sustainable way to achieve increased waste degradation along with benefits such as enhanced landfill gas (LFG) recovery, reduction in leachate pollution potential and rapid increase in landfill volumetric capacity. It also offers significant reduction in post closure management activities as leachate treatment, LFG impact on the environment and improves the potential for land reuse. The regulatory 30 year post-closure period is believed to account for attenuation of organics, metals and trace pollutants of adverse environmental consequences. Methodologies to improve the degradation rate and process are refuse shredding, nutrient addition, pH buffering, and temperature control along with moisture enhancement. Municipal Solid Waste (MSW) settlement and field capacity are of significant beneficial interest to achieve maximum utility of landfill volume and compute water requirements for rapid degradation using bioreactor concepts. Physical and biochemical Municipal Solid Waste (MSW) characteristics were investigated with specific emphasis on the Bio-Chemical methane potential (BMP) test. The impact of waste characteristics on its compressibility and moisture retention capacity was evaluated on a laboratory scale. Traditional in-situ waste compression models from literature were used to compare with the obtained laboratory data. / Master of Science

Agricultural producers consider utilizing multiple machines to reduce field completion times for improving effective field capacity. Using a number of smaller machines rather than a single big machine also has benefits such as sustainability via less compaction risk, redundancy in the event of an equipment failure, and more flexibility in machinery management. However, machinery management is complicated due to logistics issues. In this work, the allocation and ordering of field paths among a number of available machines have been transformed into a solvable Vehicle Routing Problem (VRP). A basic heuristic algorithm (a modified form of the Clarke-Wright algorithm) and a meta-heuristic algorithm, Tabu Search, were employed to solve the VRP. The solution considered optimization of field completion time as well as improving the field efficiency. Both techniques were evaluated through computer simulations with 2, 3, 5, or 10 vehicles working simultaneously to complete the same operation. Furthermore, the parameters of the VRP were changed into a dynamic, multi-depot representation to enable the re-route of vehicles while the operation is ongoing. The results proved both the Clarke-Wright and Tabu Search algorithms always generated feasible solutions. The Tabu Search solutions outperformed the solutions provided by the Clarke-Wright algorithm. As the number of the vehicles increased, or the field shape became more complex, the Tabu Search generated better results in terms of reducing the field completion times. With 10 vehicles working together in a real-world field, the benefit provided by the Tabu Search over the Modified Clarke-Wright solution was 32% reduction in completion time. In addition, changes in the parameters of the VRP resulted in a Dynamic, Multi-Depot VRP (DMDVRP) to reset the routes allocated to each vehicle even as the operation was in progress. In all the scenarios tested, the DMDVRP was able to produce new optimized routes, but the impact of these routes varied for each scenario. The ability of this optimization procedure to reduce field work times were verified through real-world experiments using three tractors during a rotary mowing operation. The time to complete the field work was reduced by 17.3% and the total operating time for all tractors was reduced by 11.5%. The task of a single large machine was also simulated as a task for 2 or 3 smaller machines through computer simulations. Results revealed up to 11% reduction in completion time using three smaller machines. This time reduction improved the effective field capacity.

Made available in DSpace on 2014-06-11T19:24:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-08-15Bitstream added on 2014-06-13T19:52:14Z : No. of bitstreams: 1 gamero_ac_me_botfca.pdf: 483268 bytes, checksum: 3659e817c39e10f899492793bab9e26c (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A compactação do solo afeta o desenvolvimento das plantas, bem como pode interferir nos níveis de produtividade das culturas. Com o intuito de diminuir o grau de compactação do solo, operações de manejo, como a subsolagem, que visam o rompimento da camada subsuperficial compactada, são realizadas. Este trabalho teve como objetivo estudar o desempenho operacional de um subsolador de hastes com curvatura lateral (“paraplow”), operando a diferentes velocidades de deslocamento do trator e profundidades de trabalho, bem como, avaliar o consumo energético demandado na operação. O experimento foi conduzido na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas - Campus de Botucatu/UNESP, no ano de 2007. O solo da área experimental foi classificado como Nitossolo Vermelho Distroférrico, textura muito argilosa. O delineamento experimental utilizado foi em blocos casualizados e esquema fatorial 3 x 2, com quatro repetições. Os tratamentos foram compostos da combinação de três velocidades de deslocamento definidas em função do escalonamento de marchas do trator utilizado (A1, A2 e B1) e duas profundidades de trabalho do equipamento utilizado para a mobilização do solo (0,25 e 0,35 m). Foram avaliados os dados referentes à mobilização do solo, patinagem dos rodados, capacidade de campo, consumo de combustível, força e potência na barra de tração do trator. Os resultados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Osresultados obtidos permitiram chegar às seguintes conclusões: a) Após a regulagem em condições estáticas, o subsolador manteve as profundidades da subsolagem durante a operação em condições de campo; b) a velocidade de deslocamento não apresentou efeito significativo sobre a área de solo mobilizado; c) a velocidade de deslocamento e a capacidade de campo... / The soil compactness affects the development of the plants, as well as it can interferes in the levels of productivity of the crops. Some soil management operations, like the subsoiling, aims at the breakage of the soil compacted layer. Those operations are made with the purpose to reduce the soil compactness. This research had the objective of studying the operational performance of a subsoiler with a lateral bending (paraplow), operating to different displacement speeds and depths of work, as well as, valuing the demanded energetic consumption in the operation. The experiment carried out in the Experimental Farm Lageado, Agronomic Sciences College in the¨Julio de Mesquita Filho” University (UNESP) – Botucatu Campus /UNESP, in the year of 2007. The soil of experimental area was classified like “Nitossolo Vermelho Distroférrico”, very clay texture. The experimental design was in 3x2 factorial scheme using randomized blocks with four replications. The treatments were composed of the combination of three displacement speeds defined in function of the scheduling of marches of the tractor (A1, A2 and B1) and two work depths of the equipment used for the mobilization of the soil (0,25 and 0,35 m). The works depths were obtained by changing the height of the support of the wheel of the subsoiler, There were valued the data referring to the mobilization of the soil, tractor wheel slip, capacity of field, fuel consumption , strength and power at the bar of traction of the tractor. The results were subjected to variance analysis and the averages compared by Tukey test at 5 % of probability. The gotten results had allowed to arrive at the following conclusions: a) After adjustment in static conditions, the subsoiler maintained the depths of the subsoiling during the operation in field conditions; b) the speed of displacement did not present significant effect on the mobilized area;... (Complete abstract click electronic access below)

Orientador: Ulisses Rocha Antuniassi / Resumo: O objetivo com este trabalho foi determinar a capacidade de campo operacional de pulverizadores de barras em fazendas de produção de grãos nas cinco regiões geográficas do Brasil. O estudo se baseou em dados coletados em inspeções periódicas de pulverizadores no período de 2008 a 2018. As inspeções foram realizadas pelo Projeto de Inspeção Periódica de Pulverizadores (IPP - FCA/UNESP -Botucatu/SP), dentro das atividades do Programa de Aplicação Responsável (PAR), projeto de parceria entre a empresa Corteva Agriscience e a Fundação de Estudos e Pesquisas Agrícolas e Florestais (FEPAF). As inspeções ocorreram durante os treinamentos oferecidos para os produtores de grãos, sendo avaliados 523 pulverizadores distribuídos em 283 na região Centro-Oeste, 41 na região Nordeste, 17 na região Norte, 57 na região Sudeste e 125 na região Sul. A partir dos dados coletados nas inspeções foi possível desenvolver uma metodologia para determinar a capacidade de campo operacional dos pulverizadores e calcular valores médios para cada região brasileira. Os resultados mostraram a evolução da capacidade operacional dos pulverizadores ao longo dos anos, obtendo-se padrões regionalizados na evolução da capacidade de campo operacional. O trabalho permitiu identificar dois perfis tecnológicos bem distintos: Centro-Oeste, Nordeste e Norte com pulverizadores de maior capacidade operacional e o Sudeste e Sul com os pulverizadores de menor capacidade. A região Nordeste se destacou por ter maior capacidad... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to determine the operational field capacity of bar sprayers on grain production farms in the five geographic regions of Brazil. The study was based on data collected from periodic spraying inspections from 2008 to 2018. The inspections were performed by the Project of Periodic Inspection of Sprayers (IPP - FCA / UNESPBotucatu City / São Paulo State) related to the development of activities within a Responsible Application Program (PAR), partnership project between the company Corteva Agriscience and Agricultural and Forestry Studies and Research Foundation (FEPAF). The inspections have occurred during the training offered to grain producers evaluated 523 sprayers distributed in 283 in the Midwest, 41 in the Northeast, 17 in the North, 57 in the Southeast and 125 in the South. From the data collected in the inspections, it was possible to develop a methodology to determine the operational field capacity of the sprayers and calculate average values by the Brazilian region. The results showed that the evolution of the sprayers operational capacity over the years, obtaining regionalized standards in the evolution of the operational field capacity. In this way, the work was divided into two distinct technological profiles: Midwest, Northeast and North with sprayers with greater operational capacity and Southeast and South with sprayers with less capacity. The Northeast region have been detached for having greater average operational field capacity, with 36.25 ha h... (Complete abstract click electronic access below) / Mestre

The superior limit of water retention in soil, also known as field capacity, still is motive of discussion and research inside the academic community. This happens because the variability of soils determines the alternation of results obtained by all methods that were performed. The need of accuracy, quickness of results, and test cost are the factors that point which method should be used. The recommendation for the determination of field capacity is that it must be performed in situ ; however, due to its slow process, the method has been performed in labs. The present work was developed using data available in literature, compiled in such a way to create a database about the subject studied. A comparative analysis between the volumetric humidity values, obtained through field experiments and the volumetric humidity values estimated by the proposed methodology, and also using the different adjustment models of the water retention curve in soil. In order to establish the comparison, a regression analysis between the values of field capacity was performed using the many procedures in attempt to obtain the correlation coefficient (r) and the Wilmont concordance index (c). From the results obtained in this work it is possible to conclude that the evaluation of the proposed methodology the estimative of field capacity concerning an inflection of the retention curve when modeled by a third-degree polynomial presented performance in the class outstanding and very good in 66.5% of the cases and classes of performance very weak 16,6% and extremely bad in about 16,6% of the cases. The applied methodology did not present consistent results for the different sources of data used and in a general way, the best found / O limite superior da retenção de água no solo, também conhecido como capacidade de campo, ainda é motivo de discussão e pesquisa entre a comunidade acadêmica, pois a variabilidade dos solos determina a variação nos resultados obtidos em todos os métodos utilizados. A necessidade de acurácia, rapidez dos resultados e custo do teste é que determinam qual método deve ser utilizado. A recomendação para a determinação da capacidade de campo é de que seja realizada "in situ"; entretanto, devido ao processo ser moroso, essa tem sido realizada em laboratório. O presente trabalho foi desenvolvido utilizando dados disponíveis na literatura, reunidos de modo a formarem um banco de dados sobre o assunto em estudo. Foi feito uma análise comparativa entre os valores de umidade volumétrica, obtidos através dos experimentos no campo e os valores da umidade volumétrica estimados com a metodologia proposta e utilizando os diferentes modelos de ajuste da curva de retenção da água no solo. Para realizar a comparação foi feita analise de regressão entre os valores da capacidade de campo pelos diferentes procedimentos com o objetivo de obter o coeficiente de correlação (r) e o índice de concordância de Wilmont (c), A partir dos resultados encontrados neste trabalho concluiu-se que a avaliação da metodologia proposta, para a estimativa da capacidade de campo em função do ponto de inflexão da curva de retenção, quando modelada por um polinômio de 3° grau, apresentou classe de desempenho ótimo e muito bom (66.5%), muito fraco (16,6%) e péssimo (16,6%). A metodologia aplicada não apresentou resultados consistentes para as diferentes fontes de dados utilizadas, sendo que de maneira geral, os melhores desempenhos encontrados foram para as curvas de retenção determinadas a campo, com exceção de solos de dunas de areia.

Orientador: Sérgio Hugo Benez / Banca: Elcio Hiroyoshi Yano / Banca: Paulo Roberto Arbex Silva / Resumo: A compactação do solo afeta o desenvolvimento das plantas, bem como pode interferir nos níveis de produtividade das culturas. Com o intuito de diminuir o grau de compactação do solo, operações de manejo, como a subsolagem, que visam o rompimento da camada subsuperficial compactada, são realizadas. Este trabalho teve como objetivo estudar o desempenho operacional de um subsolador de hastes com curvatura lateral ("paraplow"), operando a diferentes velocidades de deslocamento do trator e profundidades de trabalho, bem como, avaliar o consumo energético demandado na operação. O experimento foi conduzido na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas - Campus de Botucatu/UNESP, no ano de 2007. O solo da área experimental foi classificado como Nitossolo Vermelho Distroférrico, textura muito argilosa. O delineamento experimental utilizado foi em blocos casualizados e esquema fatorial 3 x 2, com quatro repetições. Os tratamentos foram compostos da combinação de três velocidades de deslocamento definidas em função do escalonamento de marchas do trator utilizado (A1, A2 e B1) e duas profundidades de trabalho do equipamento utilizado para a mobilização do solo (0,25 e 0,35 m). Foram avaliados os dados referentes à mobilização do solo, patinagem dos rodados, capacidade de campo, consumo de combustível, força e potência na barra de tração do trator. Os resultados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Osresultados obtidos permitiram chegar às seguintes conclusões: a) Após a regulagem em condições estáticas, o subsolador manteve as profundidades da subsolagem durante a operação em condições de campo; b) a velocidade de deslocamento não apresentou efeito significativo sobre a área de solo mobilizado; c) a velocidade de deslocamento e a capacidade de campo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The soil compactness affects the development of the plants, as well as it can interferes in the levels of productivity of the crops. Some soil management operations, like the subsoiling, aims at the breakage of the soil compacted layer. Those operations are made with the purpose to reduce the soil compactness. This research had the objective of studying the operational performance of a subsoiler with a lateral bending (paraplow), operating to different displacement speeds and depths of work, as well as, valuing the demanded energetic consumption in the operation. The experiment carried out in the Experimental Farm Lageado, Agronomic Sciences College in the¨Julio de Mesquita Filho" University (UNESP) - Botucatu Campus /UNESP, in the year of 2007. The soil of experimental area was classified like "Nitossolo Vermelho Distroférrico", very clay texture. The experimental design was in 3x2 factorial scheme using randomized blocks with four replications. The treatments were composed of the combination of three displacement speeds defined in function of the scheduling of marches of the tractor (A1, A2 and B1) and two work depths of the equipment used for the mobilization of the soil (0,25 and 0,35 m). The works depths were obtained by changing the height of the support of the wheel of the subsoiler, There were valued the data referring to the mobilization of the soil, tractor wheel slip, capacity of field, fuel consumption , strength and power at the bar of traction of the tractor. The results were subjected to variance analysis and the averages compared by Tukey test at 5 % of probability. The gotten results had allowed to arrive at the following conclusions: a) After adjustment in static conditions, the subsoiler maintained the depths of the subsoiling during the operation in field conditions; b) the speed of displacement did not present significant effect on the mobilized area;... (Complete abstract click electronic access below) / Mestre

Drought is the major environmental factor affecting crop growth, yield and quality. Two experiments were conducted to understand rice genotypic variability responses to drought stress conditions during seed germination and early-seedling growth. In Experiment I, the influence of wide range of osmotic stress on seed germination properties of 15 rice cultivars were studied using polyethylene glycol media. In Experiment II, seedling morph-physiological parameters including root traits were quantified by subjecting rice seedlings to three different soil moisture treatments, 100, 66 and 33% field capacity. Rice cultivars differed in their response to drought at both the stages. Cultivars were classified into different drought tolerant groups based cumulative drought response indices. Based on seed- and early-season growth and developmental responses, RU1104122, Rex, CL111 and RU1304154 were identified as drought tolerant among the rice cultivars tested. The identified tolerant cultivars will be a source for rice breeders to develop new drought tolerant cultivars.

Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-23T14:52:47Z No. of bitstreams: 1 PGCS16DA034.pdf: 2595021 bytes, checksum: a3427fca0377ac57de4e08f845323733 (MD5) / Made available in DSpace on 2018-03-23T14:52:47Z (GMT). No. of bitstreams: 1 PGCS16DA034.pdf: 2595021 bytes, checksum: a3427fca0377ac57de4e08f845323733 (MD5) Previous issue date: 2016-02-26 / Capes / It is necessary to acknowledge the retention and availability of water in the soil, they are agricultural production factors, which can be measured directly or estimated by pedotranfers. Some studies about retention and availability of water in the soil were initiated in the State of Santa Catarina, but these need to continue, mainly in the study of specific surface area (SSA) and limits of soil consistency, in the expansion of areas/regions of study, as well as use of other techniques beyond the linear multiple regression, such as artificial neural networks and regression trees. So the aim of this study was to estimate the field capacity, permanent wilting point and water available through multiple linear regressions, artificial neural networks and regression trees, in soils of the State of Santa Catarina, more efficient than the current pedotransfer functions. For this, samples of horizons of soil profiles 70 were collected for determination of physical, chemical and mineralogical properties. The soil properties were submitted to simple regression analysis and path analysis, to assess the relationship between the properties and clearly define which properties should be included in the models. They were also carried out cluster analysis by textural classes, classes of soil, lithology and classification according IN 2/2008. Eight models were defined for the estimation of field capacity (FC), permanent wilting point (PWP) and available water (AD). Linear multiple regressions were generated by the stepwise procedure, artificial neural networks and regression trees in the WEKA software. The database presented high variability, where sand acts negatively, and clay, the limits of consistency, organic carbon and specific surface area has a positive effect on water retention in the soil. For the availability of water to grain size was the property the most influential. When they were grouped by textural classes of clay soils showed the highest retention, and sandy to smaller. Already the water availability was higher in silty soils. As for lithology, the largest water retention happens in soils derived from igneous and sedimentary rocks with finer texture, and the smaller occurred in soils derived rock or sedimentary deposits with a particle size of greater diameter. For availability is the largest in derivative siltstones soils, and is lower in soils derived mainly granite and current alluvial deposits. When grouped according to their classification Cambissolos, Nitossolos and Brunos soil (suborder) showed greater water retention, and the Neossolos Quartzarênicos the lower retention and availability of water, mainly influenced by the particle size and soil organic carbon content. The normative instruction n. 2/2008 MAP (BRAZIL, 2008), is not appropriate to classify soils Santa Catarina as the availability of water, because the available water capacity did not differ between the classes, and most indicated that the classification happens directly through the available water capacity. In study estimates of the regression trees estimated better field capacity, the permanent wilting point and the availability of water than artificial neural networks and multiple linear regression. The best models to estimate the water retention were those who used the microporosity. The simplest model (content of clay, silt and organic carbon), also is an alternative for the estimation of field capacity, permanent wilting point and the availability of water in the soil / É necessário o conhecimento da retenção e disponibilidade de água no solo, pois são fatores de produção agrícola, os quais podem ser medidos diretamente ou estimados por pedofunções. Alguns trabalhos de retenção e disponibilidade de água no solo foram iniciados no Estado de Santa Catarina, mas estes necessitam de sequência, sobretudo no estudo da área superficial específica (ASE) e limites de consistência do solo, e na ampliação das áreas/regiões de estudo, assim como uso de outras técnicas além das regressões múltiplas lineares, tais como redes neurais artificiais e árvores de regressão. Assim o objetivo deste trabalho foi estimar a capacidade de campo, ponto de murcha permanente e água disponível através de regressões múltiplas lineares, redes neurais artificiais e árvores de regressão, em solos do Estado de Santa Catarina, de forma mais eficiente do que às atuais funções de pedotransferência. Para isso, amostras dos horizontes de 70 perfis de solo foram coletadas para determinação de propriedades físicas, químicas e mineralógicas. As propriedades do solo foram submetidas à análise de regressão simples e análise de trilha, para avaliar a relação entre as propriedades, e definir quais devem ser incluídas nos modelos. Também foram realizadas análises de agrupamento por classes texturais, classes de solos, litologia e classificação segundo a instrução normativa IN 2/2008. Foram definidos oito modelos para a estimativa da capacidade de campo (CC), ponto de murcha permanente (PMP) e água disponível (AD). As regressões múltiplas lineares foram geradas pelo procedimento stepwise, e as redes neurais artificiais e as árvores de regressão no software WEKA. O banco de dados apresentou alta variabilidade, onde areia atua negativamente, e a argila, os limites de consistência, carbono orgânico e área superficial específica atuam positivamente sobre a retenção de água no solo. Para à disponibilidade de água a granulometria foi a propriedade com maior influência. Quando foram agrupados por classes texturais, os solos argilosos foram os que apresentaram maior retenção, e os arenosos a menor. Já a disponibilidade de água foi maior em solos siltosos. Quanto à litologia, a maior retenção de água aconteceu em solos derivados de rochas ígneas e sedimentares com textura mais fina, e os menores aconteceram em solos derivados de rochas ou depósitos sedimentares com granulometria de maior diâmetro. A maior disponibilidade ocorre em solos derivados de siltitos, e menor em solos derivados, principalmente, de granito e de depósitos aluvionares atuais. Quando agrupados pela classificação taxonômica os Cambissolos, Nitossolos e solos Brunos (Subordem) apresentaram maior retenção de água, e os Neossolos Quartzarênicos menor retenção e disponibilidade de água, influenciados principalmente pela granulometria e teor de carbono orgânico do solo. A instrução normativa n. 2/2008 do MAPA (BRASIL, 2008) não é adequada para classificar os solos catarinenses quanto a disponibilidade de água, pois a capacidade de água disponível não diferiu entre as classes, sendo mais indicado que a classificação aconteça diretamente através da determinação da capacidade de água disponível. No estudo das estimativas as árvores de regressão estimaram melhor a capacidade de campo, o ponto de murcha permanente e a disponibilidade de água do que as redes neurais artificiais e a regressão múltipla linear. O modelo mais simples (teor de argila, silte e carbono orgânico), pode ser utilizado para estimar a capacidade de campo, ponto de murcha permanente e disponibilidade de água no solo. Mas os melhores modelos para estimar a retenção de água foram os que incluíram a microporosidade

The purpose of the present work was to establish and to test pedotransfer functions for water retention the Rio Grande do Sul s soils. Water retention data were obtained from Solano Peraza s dissertation, Irriga System database and in the literature. The first part of this work was the collect soil water retention data and pedotransfer functions for Rio Grande do Sul soils, forming the literature data base, in a total of 24 papers and 624 database of the water retention. The samples obtained from of Solano Peraza were collected soil profiles, in a total of 86 data of water retention, and the Irriga Project provided a database with a total of 253 data of water retention. With these database, multiple regression were done to obtain the pedotransfer functions for each database, using the option stepwise , to determine water retention in a determined potential ( -1, -6, -10, -33, -100, -500 e 1500 kPa) for different soils. To test the efficiency of the equations produced, observed vs. estimated water retention, for each water potencial, were graphed on 1:1 type retention. In almost all cases, total sand presented a high association with the water retention, followed by clay and silt content. With the reduction on in water tension (increase of the original potential), the correlation increased notably. The pedotransfer equations are efficient only when they are used to estimate moisture for soil similar to those used to obtain the equations. Besides, the database feature affects the prediction capacity of the equations produced. When some soils are predominant in the database, the equations produced show the features of those soils and, when they are used to soil moisture, the error will be larger. The contents of sand and clay together with the soil bulk density best described water retention in the linear multiple regressions. Sand content had a negative relation with water retention, while clay presented a positive relation. The soil bulk density showed a negative relation with water retention the potential of 6 to 500 kPa and a positive relation with water retained at 1500 kPa. The best estimation of water retention occurred at a potential of 1500 kPa. / O trabalho foi desenvolvido com o objetivo de estabelecer e testar funções de pedotransferência para retenção de água em solos do Rio Grande do Sul. As informações de retenção de água foram obtidas das seguintes fontes: amostras da dissertação de Solano Peraza (2003), amostras obtidas pelo Sistema Irriga e amostras obtidas na Literatura. A primeira etapa do trabalho consistiu na coleta de informações de retenção de água no solo e de funções de pedotransferência para solos do Rio Grande do Sul, constituindo o banco de dados Literatura, totalizando 24 trabalhos e 624 dados de retenção de água. As amostras obtidas do banco Solano Peraza (2003) foram coletadas em cortes de estradas com exposição do perfil do solo, totalizando um banco de dados com 86 dados de retenção de água, enquanto o Projeto Irriga nos repassou um banco de dados com um total de 253 dados de retenção de água. A partir desses bancos de dados, foram feitas análises de regressão múltipla para a obtenção das funções de pedotransferência para cada banco de dados, usando a opção stepwise (SAS, 1997), para determinar o teor de água em um determinado potencial (-1, -6, -10, -33, -100, -500 e -1500 kPa) para os diferentes solos. Para testar a eficiência das equações geradas, fez-se a comparação dos teores de umidade observados com os teores estimados para cada equação em determinado potencial e, assim, confrontaram-se os dados estimados com os observados numa relação gráfica 1:1. De modo geral, a areia total apresentou maior associação com a retenção de água, sendo seguida pelo teor de argila e silte. Com a diminuição na tensão de água (aumento do potencial matricial), a correlação aumenta consideravelmente. As equações de pedotransferência só são eficientes quando usadas para estimar a umidade para os solos a partir dos quais elas foram geradas. Além disso, a característica do banco de dados afeta a capacidade preditiva das equações geradas. Quando predominam determinadas classes de solos no banco de dados, as equações geradas refletem as características daqueles solos e, quando usadas para estimar a umidade de solos de classes diferentes, o erro será maior. Os teores de areia e argila juntamente com a densidade do solo foram os parâmetros que melhor descreveram a retenção de água através das regressões múltiplas geradas. O teor de areia apresenta uma relação negativa com a retenção de água enquanto a argila relaciona-se positivamente. A densidade do solo apresenta uma relação negativa com a retenção e água para os potenciais de -6 a -500 kPa e uma relação positiva com a água retida a -1500 kPa. A melhor estimativa da retenção de água ocorre para o potencial de -1500 kPa.

Understanding the spatial and temporal dynamics of soil water and crop water stress within a field is critical for effective Variable Rate Irrigation (VRI) management. Proper VRI can result in improved protection of the crop from early onset of crop water stress while minimizing runoff and drainage losses. The objectives of this study are (1) to examine zone delineation for informing irrigation recommendations from volumetric water content (VWC) and field capacity (FC) to grow similar or greater wheat yields with less water, (2) evaluate the ability to model soil and crop water dynamics within a season and within a field of irrigated winter wheat, and evaluate the sensitivity of crop water stress, evapotranspiration and soil water depletion outputs within a water balance model with Penman-Monteith evapotranspiration (ET) in response to adjusted soil properties, spring volumetric water content (VWC), and crop coefficient model input values. Five irrigation zones were delineated from two years of historical yield and evapotranspiration (ET) data. Soil sensors were placed at multiple depths within each zone to give real time data of the VWC values within each soil profile. Soil samples were taken within a 22 ha field of winter wheat (Triticum aestivum ‘UI Magic’) near Grace, Idaho, USA multiple times during a growing season to describe the spatial variation of VWC throughout the field, and to assist in modeling soil water dynamics and crop water stress through energy balance and water balance equations. Spatial variation of VWC was observed throughout the field, and on a smaller scale within each zone, suggesting the benefit of breaking portions of the field into zones for irrigation management purposes. Irrigation events were triggered when soil sensors detected low values of VWC, with each zone receiving unique rates intended to refill to zone specific FC. Cumulative irrigation rates varied among zones and the VRI approach saved water when compared to an estimated uniform Grower Standard Practice (GSP) irrigation approach. This method of zone management with soil sampling and sensors approximately represented the VWC within each zone and proved beneficial with effective reduction of irrigation rates in every zone compared to an estimated GSP. As such, there was a delay in the premature onset of crop water stress throughout some areas of the field. Variability in soil properties and spring soil moisture were key in giving accurate values to the model in order to make proper VRI management decisions. When assessing the model sensitivity, changing the inputs such as FC, wilting point (WP), total available water (TAW), spring VWC and crop coefficient (Kc) by -4 to +4 standard deviations away from their spatially average values, impacted the outputs of the model, with Kc having a large impact all three of the outputs. Further work is needed to improve the accuracy of representing VWC throughout a field, thus improving VRI management, and there is potential benefit in using a variable crop coefficient could to more accurate VRI management decisions from a soil water depletion model.