Made available in DSpace on 2014-06-11T19:26:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-30Bitstream added on 2014-06-13T19:55:04Z : No. of bitstreams: 1 sampaioneto_gd_me_botfca.pdf: 350068 bytes, checksum: d7fadefda254167e38c242d8181ad103 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / A cafeicultura irrigada vem crescendo nos últimos anos no Brasil devido aos bons resultados apresentados em várias regiões do país, porém um dos grandes problemas de se utilizar a irrigação na cultura do café tem sido o manejo, pois são poucas as informações em relação a esse assunto. Objetivou-se com este trabalho avaliar o desenvolvimento vegetativo e as características fisiológicas do cafeeiro irrigado com diferentes lâminas de água, calculadas em função da evaporação de água do Tanque Classe A, durante as fases de expansão e granação dos frutos que são as, mas críticas da cultura em relação ao déficit hídrico. O experimento foi conduzido no período de novembro de 2011 até março de 2012, na Fazenda Nova América situada no município de Botucatu-SP, localizada nas coordenadas geográficas 22°56’ S e 48°21’W, altitude de 663m, em um cafezal da cultivar Obatã IAC 1669-20 com oito anos de idade. O experimento foi composto por seis tratamentos onde T1 foi a testemunha sem irrigação, as demais lâminas de água aplicadas foram correspondentes a 60% (T2), 80% (T3), 100% (T4), 120% (T5), 140% (T6) da evapotranspiração da cultura (Etc) calculada conforme a evaporação de água do Tanque Classe A. O crescimento de ramos e números de par de folhas, foram superiores nos tratamentos T5 e T6. O número de entrenós do T5 foi superior em relação aos demais tratamentos. As variáveis correspondentes à condutância estomática (gs) e temperatura foliar (Tf) não apresentaram diferenciação entre os tratamentos. Porém, os valores médios da assimilação líquida de carbono (A) dos tratamentos irrigados, apresentaram valores maiores em relação à testemunha sem irrigação / The purpose of the work was to evaluate vegetative development and physiological characteristics cultivated under different water depths, calculated according to the class A pan evaporation, the phases of expansion and grain formation that are overpriced, but criticism of culture in relation to water deficit. The experiment was conducted from November 2011 until March 2012, on the farm New America, in the municipality of Botucatu - SP, located by geographic coordinates 22 ° 56 'S and 48 ° 21' W, altitude of 663m, in a coffee plantation Obatã IAC 1669-20 cultivar with eight years of age. The experiment consisted of six treatments where T1 was no irrigation, other water depths were applied at 60% (T2), 80% (T3), 100% (T4), 120% (T5), 140% (T6) of crop evapotranspiration (Etc) calculated according the evaporation of water from the class A pan. The growing numbers of branches and leaf pair, were higher in treatments T5 and T6. The number of internodes of T5 was high to other treatments. The variables corresponding to stomatal conductance (gs) and leaf temperature (Tf) showed no difference between treatments. However, the mean values of net carbon assimilation (A) of irrigated treatments showed higher values compared to no irrigation

Made available in DSpace on 2014-06-11T19:32:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-10-18Bitstream added on 2014-06-13T21:04:36Z : No. of bitstreams: 1 ferreira_vm_dr_botfca.pdf: 2956673 bytes, checksum: b4054a01c8b7e08ec686723a2b0e048b (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / O objetivo deste trabalho conduzido no campo experimental da Embrapa Meio Norte, em Teresina, PI, foi determinar o Kc da melancia nos diferentes estádios fenológicos e definir a lâmina ótima, visando o manejo racional da irrigação. Os tratamentos constaram de cinco lâminas de irrigação (50, 75, 100, 125, 150% da evapotranspiração de referencia – ETo) e três cultivares de melancia (Shadow, Top Gun e Crimson Sweet). Os tratamentos foram dispostos em um delineamento experimental de blocos casualizados, com parcelas subdivididas, com quatro repetições, com as cultivares Shadow, Top Gun e Crimson Sweet nas subparcelas e as lâminas de irrigação, nas parcelas. A semeadura foi realizada em ambiente protegido, após 12 dias transcorridos foram transplantadas para o campo, em com espaçamento de 2,0 m entre fileiras e 1,0 m entre plantas. A aplicação de água foi realizada por um sistema de irrigação por gotejamento. O manejo da irrigação foi realizado diariamente, com base nos valores diários de ETo, estimados por Penman- Monteith, usando os elementos climáticos diários de temperatura do ar, umidade relativa do ar, radiação solar e velocidade do vento, os quais foram obtidos da estação agrometeorológica automática. As cultivares foram avaliadas quanto aos componentes de produção, qualidade dos frutos, eficiência do uso de água e avaliação econômica. Os valores médios de Kc foram 0,39; 0,80; 1,14; 0,59 (Crimson Sweet); 0,35; 0,72; 1,20; 0,30 (Top Gun) e 0,34; 0,58; 0,89;0,55 (Shadow), para as fases inicial, vegetativa, intermediária e maturação, respectivamente. A maior produtividade na pesquisa foi obtida pela cultivar Top Gun (41.976 kg.ha-1) com uma lâmina total de 232,78 mm. O hibrido Top Gun, destacou-se por apresentar um teor de 7,1 mg/kg de ácido ascórbico numericamente mais expressivo em... / The goal of this work, that was conducted on the Experimental Field of Embrapa Middle North, in Teresina, Piauí State, Brazil, was to appoint/set the Kc values of the watermelon at different phonological phases and set the irrigation depth optimum , in order to rationally the irrigation management. The treatments were five irrigation depths (50, 75, 100, 125, 150% of the reference evapotranspiration) and three watermelon cultivars (Shadow, Top Gun and Crimson Sweet). The treatments were placed in an experimental design of randomized blocks, with subdivided plots, with four repetitions, with cultivars (Shadow, Top Gun and Crimson Sweet) at the sub-plots and the irrigation depths at the plots. The sowing was set at a protect environment and after 12 days were transplanted to the field with 2,0m of spacing between ranks and 1,0m between plants. The application of water was held by a drip irrigation system. The irrigation management was carried out daily by soil – water balance method, at Excel spreadsheets, based on reference evapotranspiration daily values estimated by Penman – Monteith equation, using of the climatic elements: air temperature, relative humidity of the air, solar mdiation and wind speed, which were obtained from the automatic weather station. The cultivars were evaluated for the production components, fruits quality, efficiency of the water use and economic evaluation. The average values of Kc obtained were 0,39; 0,80; 1,14; 0,59 (Crimson Sweet); 0,35; 0,72; 1,20; 0,30 (Top Gun) and 0,34; 0,58; 0,89; 0,55 (Shadow), for the initial, vegetative, intermediate and maturation phase, respectively. The bighest productivity was gathered by the Top Gun cultivar (41,976 kg.ha-1) with a depth total of 232.78 mm. The hybrid Top Gun stood out for presenting a percentage of 7.1mg / kg of AASC more... (Complete abstract click electronic access below)

Orientador: Antônio Evaldo Klar / Coorientador: Aderson Soares de Andrade Junior / Banca: João Carlos Cury Saad / Banca: Raimundo Leite Cruz / Banca: Edson Alves Bastos / Banca: Claudio Ricardo da Silva / Resumo: O objetivo deste trabalho conduzido no campo experimental da Embrapa Meio Norte, em Teresina, PI, foi determinar o Kc da melancia nos diferentes estádios fenológicos e definir a lâmina ótima, visando o manejo racional da irrigação. Os tratamentos constaram de cinco lâminas de irrigação (50, 75, 100, 125, 150% da evapotranspiração de referencia - ETo) e três cultivares de melancia (Shadow, Top Gun e Crimson Sweet). Os tratamentos foram dispostos em um delineamento experimental de blocos casualizados, com parcelas subdivididas, com quatro repetições, com as cultivares Shadow, Top Gun e Crimson Sweet nas subparcelas e as lâminas de irrigação, nas parcelas. A semeadura foi realizada em ambiente protegido, após 12 dias transcorridos foram transplantadas para o campo, em com espaçamento de 2,0 m entre fileiras e 1,0 m entre plantas. A aplicação de água foi realizada por um sistema de irrigação por gotejamento. O manejo da irrigação foi realizado diariamente, com base nos valores diários de ETo, estimados por Penman- Monteith, usando os elementos climáticos diários de temperatura do ar, umidade relativa do ar, radiação solar e velocidade do vento, os quais foram obtidos da estação agrometeorológica automática. As cultivares foram avaliadas quanto aos componentes de produção, qualidade dos frutos, eficiência do uso de água e avaliação econômica. Os valores médios de Kc foram 0,39; 0,80; 1,14; 0,59 (Crimson Sweet); 0,35; 0,72; 1,20; 0,30 (Top Gun) e 0,34; 0,58; 0,89;0,55 (Shadow), para as fases inicial, vegetativa, intermediária e maturação, respectivamente. A maior produtividade na pesquisa foi obtida pela cultivar Top Gun (41.976 kg.ha-1) com uma lâmina total de 232,78 mm. O hibrido Top Gun, destacou-se por apresentar um teor de 7,1 mg/kg de ácido ascórbico numericamente mais expressivo em... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The goal of this work, that was conducted on the Experimental Field of Embrapa Middle North, in Teresina, Piauí State, Brazil, was to appoint/set the Kc values of the watermelon at different phonological phases and set the irrigation depth optimum , in order to rationally the irrigation management. The treatments were five irrigation depths (50, 75, 100, 125, 150% of the reference evapotranspiration) and three watermelon cultivars (Shadow, Top Gun and Crimson Sweet). The treatments were placed in an experimental design of randomized blocks, with subdivided plots, with four repetitions, with cultivars (Shadow, Top Gun and Crimson Sweet) at the sub-plots and the irrigation depths at the plots. The sowing was set at a protect environment and after 12 days were transplanted to the field with 2,0m of spacing between ranks and 1,0m between plants. The application of water was held by a drip irrigation system. The irrigation management was carried out daily by soil - water balance method, at Excel spreadsheets, based on reference evapotranspiration daily values estimated by Penman - Monteith equation, using of the climatic elements: air temperature, relative humidity of the air, solar mdiation and wind speed, which were obtained from the automatic weather station. The cultivars were evaluated for the production components, fruits quality, efficiency of the water use and economic evaluation. The average values of Kc obtained were 0,39; 0,80; 1,14; 0,59 (Crimson Sweet); 0,35; 0,72; 1,20; 0,30 (Top Gun) and 0,34; 0,58; 0,89; 0,55 (Shadow), for the initial, vegetative, intermediate and maturation phase, respectively. The bighest productivity was gathered by the Top Gun cultivar (41,976 kg.ha-1) with a depth total of 232.78 mm. The hybrid Top Gun stood out for presenting a percentage of 7.1mg / kg of AASC more... (Complete abstract click electronic access below) / Doutor

Orientador: José Eduardo Pitelli Turco / Banca: Antônio Carlos Barreto / Banca: Teresa Cristina Tarlé Pissarra / Resumo: A cana-de-açúcar é uma cultura de fundamental importância para o país. Grande parte dos índices de seca ou estiagem agrícola consideram, ou somente a chuva, ou em alguns casos a interação entra água disponível no solo, como passivas, na evapotranspiração real e a potencial. Com este trabalho o objetivo foi de determinar o índice de estresse hídrico diário baseado na termometria a infravermelho, para a cana-de-açúcar em superfícies irrigadas. Foram avaliados dados meteorológicos do ambiente, o índice de estresse hídrico da planta com o uso do termômetro de infravermelho, o potencial de água no solo e analisada a condução do sistema produtivo durante o período de coleta de dados. A pesquisa foi desenvolvida na área experimental do Departamento de Engenharia Rural da FCAV/UNESP, em uma estrutura denominada "Bacia Hidrográfica Experimental", utilizando superfícies caracterizadas como HNI (superfície horizontal sem irrigação), HI (superfície horizontal irrigada), 20N (superfície com 20% de declividade, exposição norte e irrigada), 40N (superfície com 40% de declividade, exposição norte e irrigada), 20S (superfície com 20% de declividade, exposição sul e irrigada), e 40S (superfície com 40% de declividade, exposição sul e irrigada). Os resultados deste estudo indicaram que: o índice de estresse hídrico diário acima de 5°C compromete negativamente a produtividade da cultura; a superfície de exposição sul com 20% de declividade apresentou maior produtividade sobre as demais superfícies estudadas; e a exposição e declividade do terreno influenciaram no manejo da irrigação e na produtividade para cada superfície estudada / Abstract: The sugarcane is a crop of vital importance to the country. Much of the drought indices or agricultural drought consider, or only the rain, or in some cases the interaction enters water available in the soil, as passive, the actual evapotranspiration and potential. With this work, the objective was to enter the daily water stress index based on the infrared thermometry, for sugarcane in irrigated areas. They evaluated environmental meteorological data, the water stress index of the plant with the use of infrared thermometer, the water potential in the soil and analyzed driving the production system during the data collection period. The research was conducted in the experimental area of the Department of Rural Engineering FCAV / UNESP, in a structure called "Basin Experimental", using surfaces characterized as HNI (horizontal surface without irrigation), HI (irrigated horizontal surface), 20N (surface 20% slope, north and irrigated exposure), 40N (surface with 40% slope, north and irrigated exposure), 20S (surface with 20% slope, south and irrigated exposure) and 40S (surface with 40% slope, south and irrigated exposure). The results of this study indicated that: the daily water stress index above 5°C adversely compromises the productivity of culture; south exhibition area with 20% slope had higher productivity on the other surfaces studied and exposure; and slope of the terrain influence the management of irrigation and productivity for each study area / Mestre

Made available in DSpace on 2014-06-11T19:30:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-08-28Bitstream added on 2014-06-13T19:00:11Z : No. of bitstreams: 1 delgado_lgm_me_botfca.pdf: 570387 bytes, checksum: a67a86a29b4a2709b5aef452fc1ad154 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A quantificação da necessidade hídrica para produção de mudas é de suma importância, pois além de afetar o desenvolvimento e a qualidade da planta, a escassez dos recursos hídricos se torna cada vez mais frequente. Este estudo teve por objetivo analisar os efeitos do manejo hídrico (lâmina bruta e freqüência de irrigação) no desenvolvimento e qualidade das mudas de Ingá (Inga vera Willd. subsp. affinis (D.C.) T.D. Penn.), Canafístula (Peltophorum dubium (Spreng.) Taub.) e Jatobá (Hymenaea courbaril var. Stilbocarpa (Hayne) Y.T. Lee & Langenh) e determinar o manejo hídrico mais adequado para produção de mudas de cada espécie do ponto de vista de qualidade e eficiência do recurso hídrico. O experimento foi conduzido no Viveiro do Departamento de Recursos Naturais/Setor de Ciências Florestais, na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas (FCA) da UNESP, no município de Botucatu – SP. O substrato utilizado foi o produto comercial denominado Carolina Soil Florestal. O delineamento estatístico foi um fatorial (3X2) inteiramente casualizado , constituído dos seguintes fatores: 3 lâminas brutas (6, 10 e 14 mm) e 2 frequências de irrigação (2 e 4 vezes ao dia) para cada espécie. Cada experimento foi composto por seis tratamentos, sendo cada tratamento com quatro repetições, cada qual composta por 54 plantas (12 úteis/repetição), totalizando 48 plantas por tratamento. Foram avaliadas as seguintes características nas mudas: altura da parte aérea (H); diâmetro de colo (DC); massas de matéria seca da parte aérea (MSA), das raízes (MSR) e total (MST); estruturação das raízes; transpiração; sobrevivência em vasos mantidos sem irrigação. Para as espécies Inga vera Willd. Subsp. affinis (D.C.)... / The quantification of water requirement for seedlings’ production is vital because, besides affecting the development and quality of the plant, the scarcity of resources becomes more and more frequent. This study aims to analyze the effects of water management (brute blade and irrigation frequency) on the development and quality of Inga seedlings (Inga vera Willd. subsp. affinis (D.C.) T.D. Penn.), Senna seedlings (Peltophorum dubium (Spreng.) Taub.) and Jatoba seedlings (Hymenaea courbaril var. Stilbocarpa (Hayne) Y.T. Lee & Langenh) and determine the most appropriate water management for seedlings production of each specie when it comes to quality and efficiency of the water resource. The experiment was made at the arboretum of the Natural Resources Department/Forest Sciences Sector, at Lageado Experimental Farm, which belongs to UNESP Agronomic Sciences College (FCA), in Botucatu – SP. The utilized substratum was a commercial product which is called “Carolina Soil Florestal®”. The statistical design was one factorial (3X2) completely randomized, constituted by the following agents: 3 irrigation depths (6, 10 and 14 mm) and two irrigation frequencies (twice and four times a day) for each... (Complete abstract click electronic access below)

Orientador: Magali Ribeiro da Silva / Banca: Antonio Evaldo Klar / Banca: Gisele Ferreira / Resumo: A quantificação da necessidade hídrica para produção de mudas é de suma importância, pois além de afetar o desenvolvimento e a qualidade da planta, a escassez dos recursos hídricos se torna cada vez mais frequente. Este estudo teve por objetivo analisar os efeitos do manejo hídrico (lâmina bruta e freqüência de irrigação) no desenvolvimento e qualidade das mudas de Ingá (Inga vera Willd. subsp. affinis (D.C.) T.D. Penn.), Canafístula (Peltophorum dubium (Spreng.) Taub.) e Jatobá (Hymenaea courbaril var. Stilbocarpa (Hayne) Y.T. Lee & Langenh) e determinar o manejo hídrico mais adequado para produção de mudas de cada espécie do ponto de vista de qualidade e eficiência do recurso hídrico. O experimento foi conduzido no Viveiro do Departamento de Recursos Naturais/Setor de Ciências Florestais, na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas (FCA) da UNESP, no município de Botucatu - SP. O substrato utilizado foi o produto comercial denominado Carolina Soil Florestal. O delineamento estatístico foi um fatorial (3X2) inteiramente casualizado , constituído dos seguintes fatores: 3 lâminas brutas (6, 10 e 14 mm) e 2 frequências de irrigação (2 e 4 vezes ao dia) para cada espécie. Cada experimento foi composto por seis tratamentos, sendo cada tratamento com quatro repetições, cada qual composta por 54 plantas (12 úteis/repetição), totalizando 48 plantas por tratamento. Foram avaliadas as seguintes características nas mudas: altura da parte aérea (H); diâmetro de colo (DC); massas de matéria seca da parte aérea (MSA), das raízes (MSR) e total (MST); estruturação das raízes; transpiração; sobrevivência em vasos mantidos sem irrigação. Para as espécies Inga vera Willd. Subsp. affinis (D.C.)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The quantification of water requirement for seedlings' production is vital because, besides affecting the development and quality of the plant, the scarcity of resources becomes more and more frequent. This study aims to analyze the effects of water management (brute blade and irrigation frequency) on the development and quality of Inga seedlings (Inga vera Willd. subsp. affinis (D.C.) T.D. Penn.), Senna seedlings (Peltophorum dubium (Spreng.) Taub.) and Jatoba seedlings (Hymenaea courbaril var. Stilbocarpa (Hayne) Y.T. Lee & Langenh) and determine the most appropriate water management for seedlings production of each specie when it comes to quality and efficiency of the water resource. The experiment was made at the arboretum of the Natural Resources Department/Forest Sciences Sector, at Lageado Experimental Farm, which belongs to UNESP Agronomic Sciences College (FCA), in Botucatu - SP. The utilized substratum was a commercial product which is called "Carolina Soil Florestal®". The statistical design was one factorial (3X2) completely randomized, constituted by the following agents: 3 irrigation depths (6, 10 and 14 mm) and two irrigation frequencies (twice and four times a day) for each... (Complete abstract click electronic access below) / Mestre

Software as a service (SaaS) is a primary working pattern and a significant application model for next generation Internet application. Web GIS services are the new generation of the Software as a service that can provide the hosted spatial data and GIS functionalities to the practical customized applications. This study focused on developing a webGIS based application, Soil Moisture-Based Irrigation Scheduling Tool (SMIST), for predicting soil moisture in the next seven days using the soil moisture diagnostic equation (SMDE) and the upcoming seven precipitation forecasts made by the National Weather Service (NWS), and ultimately producing an accurate irrigation schedule based on the predicted soil moisture. The SMIST is expected to be capable of improving the irrigation efficiency to protect groundwater resources in the Texas High Plains and reducing the cost of energy for pumping groundwater for irrigation, as an essential public concern in this area. The SMIST comprised an integration of web-based programs, a Hydrometeorological model, GIS, and geodatabase. It integrates two main web systems, the soil moisture estimating web application for irrigation scheduling based on the soil moisture diagnostic equation (SMDE), and an agricultural field delineation webGIS application to prepare input data and the model parameters. The SMIST takes advantage of the latest historical and forecasted precipitation data to predict soil moisture in the user-specified agricultural field(s). In this regard, the next seven days soil moisture versus the soil moisture threshold for normal growth would be presented in the result page of the SMIST to help users to adjust irrigation rate and sequence.

Thesis (MScAgric (Soil Science))--University of Stellenbosch, 2008. / In order to produce table grapes of export quality economically, irrigation must be practised conservatively without adversely affecting the crop. To use water as conservatively as possible effective irrigation scheduling practices must be applied. The highest water use efficiency (WUE) is only possible if irrigation scheduling practices lower the amount of water applied, while at the same time they increase the yield. The first aim of this project is to investigate whether current irrigation practices make efficient use of water by comparing irrigation requirements determined using theoretical models with actual irrigation applied for two seasons (2005/6 and 2006/7). Secondly, the effect of cumulative irrigation on the chemical status of soil in 16 blocks was investigated to establish whether nutrient leaching as a result of differential water use may have had an influence on yield. Six blocks (three dripper and three microsprinkler blocks) were selected and irrigation requirements were determined using evaporation pan calculations, SAPWAT and Vinet and compared with actual irrigation applications. Furthermore, a yield-irrigation index (kg/m3) and an income-irrigation index (R/m3) were determined for each of the six blocks and compared. To investigate the effect of cumulative water use on the chemical status of the soils of 16 blocks, soil samples were taken and analysed for pH (1M KCl), EC (1:5); soluble cations and anions (Ca, Mg, Na, K, SO4, NO3, and Cl), ammonium acetate extractable cations (Ca, Mg, Na and K) and micro elements (Zn, Fe, Mn, Cu and B). The irrigation requirements predicted by the different irrigation scheduling methods are variable. For Vinet, the irrigation requirement determined for microsprinkler irrigation is much higher than that determined using the evaporation pan or SAPWAT approaches. Comparison of the irrigation applied to each of these blocks does not clarify whether any irrigation scheduling takes place. Results showed a relationship between the yield-irrigation index and income-irrigation index. It has not however been verified whether this relationship is statistically significant.

The objectives of the thesis: • to analyse evapotranspiration of Norway spruce seedlings in irrigated and non-irrigated fields by applying lysimetric method; • to determine crop coefficient of spruce seedlings; • to measure dynamics of soil humidity during vegetation period; • to determine influence of irrigation regime on qualitative indices of spruce seedlings; • to determine optimal irrigation regime; • to set economic advantage of irrigation of Norway spruce seedlings. / Darbo uždaviniai: • ištirti paprastosios eglės sodinukų suminį išgaravimą drėkinamuose ir nedrėkinamuose plotuose lizimetriniu metodu; • nustatyti eglės sodinukų biologinius koeficientus; • įvertinti dirvožemio drėgmės dinamiką vegetacijos laikotarpiu; • nustatyti drėkinimo režimo įtaką eglės sodinukų kokybiniams rodikliams; • nustatyti optimalų drėkinimo režimą; • nustatyti paprastosios eglės sodinukų drėkinimo ekonominį efektyvumą.

A well-managed irrigation scheduling system needs a rapid, preCIse, simple, costeffective and non-destructive soil water content sensor. The PRl profile probe and Diviner 2000 were used to determine the timing and amount of irrigation of three cover crops (Avena sativa L., Secale cereale L. and Lolium multiflonlm Lam.), which were planted at Cedara, KwaZulu-Natal. The PRl profile probe was first calibrated in the field and also compared with the Diviner 2000. For the calibration of the PRl profile probe the factory-supplied parameters (aJ = 8.4 and ao = 1.6) showed good correlation· compared to the soil-estimated parameters (aJ = 11.04 and ao = 1.02). The factorysupplied parameters gave a linear regression coefficient (r2 ) of 0.822 and root mean square error (RMSE) of 0.062. The soil-estimated parameter showed a linear regression coefficient of 0.820 with RMSE of 0.085. The comparison between the soil water content measured using the PR1 profile probe and Diviner 2000 showed a linear regression coefficient of 0.947 to 0.964 with a range of RMSE of 0.070 to 0.109 respectively for the first 100 to 300 mm soil depths. The deeper depths (400, 600 and 1000 mm) showed a linear regression coefficient ofO.716to 0.810 with a range of 0.058 to 0.150 RMSE. These differences between the shallow and deeper depths could be due to soil variability or lack of good contact between the access tube and the surrounding soil. To undertake irrigation scheduling using the PRl profile probe and Diviner 2000, the soil water content limits were determined using field, laboratory and regression equations. The field method was done by measuring simultaneously the soil water content using the PR1 profile probe and soil water potential using a Watermark sensor and tensiometers at three depths (100, 300 and 600 mm) from a 1 m2 bare plot, while the soil dries after being completely saturated. The retentivity function was developed from these measurements and the drained upper limit was estimated to be 0.355 m3 m-3 when the drainage from the pre-wetted surface was negligible. The lower limit was calculated at -1500 kPa and it was estimated to be 0.316 m3m,3. The available soil water content, which is the difference between the upper and lower limit, was equal to 0.039 m3 m,3. In the laboratory the soil water content and matric potential were measured from the undisturbed soil samples taken from the edge of the 1 m2 bare plot before the sensors were installed. Undisturbed soil samples were taken using a core sampler from 100 to 1000 mm soil depth in three replications in 100 mm increments. These undisturbed soil samples were saturated and subjected to different matric potentials between -1 to -1500 kPa. In the laboratory, the pressure was increased after the cores attained equilibrium and weighed before being subjecting to the next matric potential. The retentivity function was then developed from these measurements. The laboratory method moved the drained upper limit to be 0.390 m3 m,3 at -33 kPa and the lower limit be 0.312 m3m-3 at -1500 kPa. The regression equation, which uses the bulk density, clay and silt percentage to calculate the soil water content at a given soil water potential, estimated the drained upper limit to be 0.295 m3m-3at -33 kPa and the lower limit 0.210 m3 m,3 at -1500 kPa. Comparison was made between the three methods using the soil water content measured at the same soil water potential. The fieldmeasured soil water content was not statistically the same with the laboratory and estimated soil water content. This was shown from the paired-t test, where the probability level (P) for the laboratory and estimated methods were 0.011 and 0.0005 respectively at 95 % level of significance. However, it showed a linear regression coefficient of 0.975 with RMSE of 0.064 when the field method was compared with the laboratory method. The field method showed a linear regression coefficient of 0.995 with RMSE of 0.035 when compared with the estimated method. The timing and amount of irrigation was determined using the PR1 profile probe and Diviner 2000. The laboratory measured retentivity function was used to define the fill (0.39 m3 m-3 ) and high refill point (0.34 m3 m-3 ). The soil water content was measured using both sensors two to three times per week starting from May 29 (149 day of year, 2002) 50 days after planting until September 20 (263 day of year) 11 days before harvesting. There were five irrigations and twenty rainfall events. The next date of irrigation was predicted graphically using, the PRl profile probe measurements, to be on 3 September (246 day of year) after the last rainfall event on 29 August (241 day of year) with 8 mm. When the Diviner 2000 was used, it predicted two days after the PRl profile probe predicted date. This difference appeared since the Diviner 2000-measured soil water content at the rooting depth was slightly higher than the PRl profile probe measurements. The amount of irrigation was estimated using two comparable methods (graphic and mathematical method). The amount of irrigation that should have been applied on 20, September (263 day of year) to bring the soil water content to field capacity was estimated to be 4.5 hand 23 mm graphically and 5.23 hand 20 mm mathematically. The difference between these two methods was caused due to the error encountered while plotting the correct line to represent the average variation in soil water content and cumulative irrigation as a function of time. More research is needed to find the cause for the very low soil water content measurements of the PRI profile probe at some depths. The research should be focused on the factors, which could affect the measurement of the PRl profile probe and Diviner 2000 like salinity, temperature, bulk density and electrical conductivity. Further research is also needed to extend the non-linear relationship between the electrical resistance of the sensor and soil water potential up to -200 kPa. This non-linear equation of the Watermark is only applicable within the range of soil water potential between -10 and -100 kPa. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.