Sustainable Built Environments Senior Capstone Project / This paper examines Subsurface Drip Irrigation(SDI) as a solution to water conservation in landscape irrigation. This is a problem because of the drought that the southwestern United States is experiencing, and the amount of water that landscapes utilize and which is ultimately wasted due to inefficient practices. Subsurface drip irrigation represents a potential solution due to its high efficiency and water saving ability; however, there are some problems within it as a system. Utilizing a multiple case studies approach, this paper looked at three of the top irrigation companies, Rain Bird, Toro, and Netafim, and examined how they innovated to overcome the problems with SDI. Synthesizing the best and most effective practices from each company, a model for improving SDI was generated.

Knowing the concentrations of the nutrient elements in soils is important due to their toxic effect on humans and the environment. The aims of this study were to assess the effects of water quality, depths and distances of lateral installation on soil chemical properties during turfgrass cultivation. A field experiment was conducted using a Split Split Plot design based on the Randomized complete Block (RCB) with two treatments (well’s and wastewater), and eight sub-treatments (45 and 60 cm distance of the laterals and 15, 20, 25, and 30 cm depths of laterals) in three replicates on a sandy-loam soil, in Shahrekord, Iran. Soil samples were collected from 0-30 and 30-60 cm depth for measuring nitrate (NO3-), electrical conductivity (EC), and pH at the end of the experiment. During the experiment, fecal coliform (FC) were also measured at the soil surface. Results indicated that by increasing lateral distance, NO3- level increased in both layers. With installing laterals in deeper levels, NO3- concentration decreased at the beginning, then increased in the first layer, whereas in the second layer NO3- concentration decreased. In addition, installing laterals in deeper depth, caused an increase in soil EC in the top layer, but a decrease in the lower layer. However, the results showed that there was no significant effect of experimental factors on soil pH. The results also show that with increasing laterals depth, Fc level decreased at the soil surface.

Master of Science / Department of Agronomy / Scott A. Staggenborg / In recent years, subsurface drip irrigation (SDI) acres have increased substantially. The use of SDI on corn (Zea Mays L.) in the Great Plains has increased due to increased land costs, reduced irrigation water availability, and higher commodity prices. Applying phosphorus (P) fertilizer through a SDI system becomes a major advantage, but further investigation of the interaction between water and fertilizer is needed. Sub-surface drip irrigation systems can be used to better improve the application efficiencies of fertilizers, applying in wet soil-root zones can lead to better uptake of soil applied materials. The objectives of this study were to determine how corn responds to P fertilizer applied via SDI and to create methodologies to simulate fertilizer and irrigation water compatibility tests for use in SDI systems. A plot sized SDI system was installed near Manhattan, KS to evaluate P treatments. Eight separate P fertilizers were applied via SDI mid-season at a rate of 34 kg P2O5 ha-1 and split-plots were created with 2x2 starter band at planting. Nitrogen was a non-limiting factor, with 180 kg N ha-1 applied as urea. Both starter fertilizer and injected fertilizer affected corn grain yield as indicated by the starter by treatment interaction. Split applying starter fertilizer at planting increased yield. A secondary laboratory study was conducted to evaluate the water and fertilizer interactions. A filtration system was used to simulate field conditions and each fertilizer/water mix was filtered through a 400 mesh filter paper to evaluate fertilizer precipitant formation. Sixteen common fertilizers were analyzed with different rates of Avail. Differences were observed between fertilizer treatments, visually and quantitatively. A secondary P soil movement field study was performed to quantify P concentrations around the SDI emitter. Soils were sampled in a 30.5 cm by 30.5 cm square adjacent to the emitter on a control treatment and a fertilized treatment, in both years of the study. Visual and quantitative differences were observed between the two treatments in both years of the study. When P fertilizers were added to the SDI system, higher P concentrations were found very close to the emitter orifice. Control treatments exhibited lower P concentrations around the emitter than fertilized treatments.

The site-specific management of alfalfa has not been well-evaluated, despite the economic importance of this crop. The objectives of this work were to i) characterize the effects of soil moisture deficits on alfalfa and alfalfa yield components and ii) evaluate the use of canopy reflectance patterns in measuring treatment-induced differences in alfalfa yield. A randomized complete block design with five replicates of subsurface drip irrigation (SDI) and rainfed treatments of alfalfa was established at the University of Kentucky Animal Research Center in 2003. Potassium, as KCl, was broadcast on split-plots on 1 October 2004 at 0, 112, 336, and 448 kg K2O ha-1. In the drought year of 2005, five harvests (H1 - H5) were taken from each split-plot and from four locations within each SDI and rainfed plot. One day prior to each harvest, canopy reflectance was recorded in each plot. Alfalfa yield, yield components, and leaf area index (LAI) were determined. In 2005, dry matter yields in two harvests and for the seasonal total were increased (Pandlt;0.05) by SDI, but SDI did not affect crown density. Herbage yield was strongly associated with yield components but yields were most accurately estimated from LAI. Canopy reflectance within blue (450 nm), red (660 nm) and NIR bands were related to LAI, yield components, and yield of alfalfa and exhibited low variance (cv andlt; 15%) within narrow ( 0.125 Mg ha-1) yield ranges. Red-based Normalized Difference Vegetation Indices (NDVIs) and Wide Dynamic Range Vegetation Indices (WDRVIs) were better than blue-based VIs for the estimation of LAI, yield components, and yield. Decreasing the influence of NIR reflectance in VIs by use of a scalar (0.1, 0.05, or 0.01) expanded the range of WDRVI-alfalfa yield functions. These results indicate that VIs may be used to estimate LAI and dry matter yield of alfalfa within VI-specific boundaries.

Devido à crise que o setor sucroenergético vem sofrendo ultimamente, mediante baixas nas cotações de açúcar e etanol nos mercados internacionais, a técnica de irrigação em cana-de-açúcar vem passando por alguns questionamentos quanto a viabilidade de implantação dos sistemas. Diante disso, novos sistemas de irrigação vêm surgindo no meio sucroenergético em busca da redução de perdas de água por evaporação e lixiviação e, também buscando uma maior longevidade de canaviais a fim de obter maior lucro líquido ao longo da vida útil da lavoura. A exemplo disso tem-se o sistema de gotejamento subsuperficial já bastante difundido na Austrália. Outro aspecto é a aplicação de vinhaça em cana-de-açúcar, cuja técnica vem sendo adotada há muito tempo visto que promove melhorias nas condições físico-química do solo além de promover economias com redução da aplicação de fertilizantes minerais visto que a vinhaça é rica no nutriente potássio. Diante disso, buscouse conduzir uma pesquisa sobre fertirrigação com aplicação de vinhaça e adubação mineral, em diferentes doses, via gotejamento subsuperficial em um Argissolo vermelho-amarelo com a variedade de cana-de-açúcar CTC15, buscando verificar os seus efeitos na produtividade da variedade e parâmetros biométricos, visto que, irrigação por gotejamento subsupercial em cana-de-açúcar é uma tecnologia relativamente nova para cultura no Brasil. Portanto, foi instalado um experimento de campo em área de aproximadamente 1600 m2, composto por 6 tratamentos compostos de diferentes doses de vinhaça, adubação mineral e sequeiro, e 4 repetições, em delineamento inteiramente casualizado, conduzidos por duas safras de cana (2013-2014 e 2014-2015), sendo o T1 sem irrigação e com adubação convencional junto ao plantio, T2 fertirrigado convencionalmente, T3 ½ DoseCETESB, T4 dose calculada a partir dos critérios da norma P4.231/2015 (DoseCETESB), T5 2xDoseCETESB e T6 3xDoseCETESB. O manejo da irrigação foi realizado por tensiômetros instalados em profundidades de 20, 40 e 60 cm. Os parâmetros avaliados foram: biometria completa da parte aérea (altura de planta, comprimento de limbo foliar, largura de limbo foliar, distância entre internódios, número de colmos, diâmetro de colmos, número de folhas e de perfilhos, clorofila a, b e total), produção por área e avaliação tecnológica (Brix, Pureza, Fibra, Cinzas e ATR). Os parâmetros foram avaliados por análise estatística de variância e teste de comparação entre médias por Tukey a 5% de probabilidade. Diante dos resultados obtidos, comparado à condição de sequeiro (T1), a irrigação exercida no ciclo da cana planta promoveu ganhos em número de perfilhos da ordem de 16%, número de colmos na ordem de 10% e largura de limbo foliar em 15%. A fertirrigação com vinhaça no ciclo de primeira soca, em comparação ao sequeiro (T1), promoveu ganhos de 13% para altura de plantas, 5% para comprimento de folhas, 12% para número de perfilhos e 4% para largura de limbo foliar. E não foram encontradas diferenças estatísticas para clorofila a, b e total e nem para parâmetros tecnológicos nos dois ciclos. O tratamento que melhor respondeu a fertirrigação com vinhaça em produtividade foi T4 (DoseCETESB) obtendo um valor de 190 ton ha-1. / Due to low sugar and ethanol prices in international markets, questions have arisen about the economic feasibility of implementing new irrigation techniques. Consequently, irrigation systems with reduced leaching and evaporative water loss, and with greater longevity, are being developed to achieve higher net income for sugarcane. The use of subsurface drip is already widespread in Australia, for example. One such management technique is the use of vinasse in sugarcane crops in Brazil. Vinasse has a long history of use in sugarcane production in Brazil, since it promotes improvements in the physical-chemical conditions of the soil and reduces the use of mineral fertilizers, as it is rich the potassium. This research relates to subsurface drip fertigation of the CTC15 variety of sugarcane in a redyellow Argisol, with vinasse and mineral fertilizer. The objective was to characterize the effect of fertigation on yield and several biometric parameters, since subsurface drip irrigation/fertigation is a relatively new technology for sugarcane production in Brazil. A drip irrigation system was installed in a 1600 m2 field, consisting of 4 replications of 6 treatments with different vinasse doses, mineral fertilizer and rainfed conditions, in a completely randomized design. The treatments were T1: No irrigation and conventional fertilization at planting, T2: fertigation at conventional fertilizer levels, T3: fertigation at ½ the standard P4.231/2015 CETESB rate, T4: fertigation at the standard CETESB rate, T5: fertigation at twice the CETESB rate and T6: fertigation at three times the CETESB rate. Data were collected for the 2013-2014 and 2014-2015 sugarcane crops. Irrigation was scheduled based on the moisture content in tensiometers installed at 20, 40 and 60 cm depth. The parameters evaluated were complete shoot biometrics (plant height, leaf blade length, width of leaf blade, the distance between internodes, number of stems, stalk diameter, number of leaves and tillers, chlorophyll a, b and total chlorophyll), crop yield, and sugarcane quality (Brix, Purity, Fiber, Embers and ATR). The parameters were evaluated by statistical analyses of variances, and comparison test of means by Tukey at 5% probability. Based on these results, compared to rainfed condition (T1), irrigation improved tiller number by 16 %, culm number by 10%, and width of leaf blade at 15%. The fertigation with vinasse in the first ratoon cycle, improved plant height by 13%, sheet length by 5%, number of tillers by 12%, and width of leaf blade by 4%. There were no statistical differences in chlorophyll A, chlorophyll B, total chlorophyll and sugarcane quality in either of the two crop cycles. The T4 treatment, fertigation at the standard CETESB rate, had the best yield response to fertigation with vinasse (190 ton ha-1).

The goal of this research was to evaluate the application uniformity of subsurface drip distribution systems and the recovery of emitter flow rates. Emission volume in the field, and laboratory measured flow rates were determined for emitters from three locations. Additionally, the effects of lateral orientation with respect to slope on emitter plugging was evaluated. Two different emitters were tested to evaluate slope effects on emitter plugging (type Y and Z). The emitters were alternately spliced together and installed in an up and down orientation on slopes of 0, 1, 2 and 4% and along the contour on slopes of 1 and 2%. The emitters were covered with soil and underwent a simulated year of dosing cycles, and then flushed with a flushing velocity of 0.6 m/s. Initial flow rates for the two emitter types were 2.38 L/hr with a C.V. of 0.07. There was no significant difference in flow rates among slopes for type Y emitters, but there was a significant difference between the 1% and 2 % contour slopes for type Z emitters. Application uniformity of three different laterals at each site was evaluated. Sections of the lateral from the beginning, middle and end were excavated and emission volumes were recorded for each emitter. Application uniformity of laterals ranged from 48.69 to 9.49%, 83.55 to 72.60%, and 44.41 to 0% for sites A, B, and C, respectively. Mean emitter flow rate was 2.21, 2.24, and 2.56 L/hr for sites A, B, and C, respectively under laboratory conditions. Application uniformity under laboratory conditions ranged from 70.97 to 14.91%, 86.67 to 79.99%, and 85.04 to 0.00% for sites A, B, and C, respectively. A flushing velocity of 0.15 m/s with no chlorination, shock chlorination of 3400 mg/L and flushing velocity of 0.15 m/s, and shock chlorination of 3400 mg/L and flushing velocity of 0.6 m/s treatment regiments were applied to all laterals collected to assess emitter flow rate recovery to the nominal flow rate published by the manufacturer. All laterals showed an increase in the number of emitters within 10% of the published nominal flow rate.

The goal of this research was to evaluate the application uniformity of subsurface drip distribution systems and the recovery of emitter flow rates. Emission volume in the field, and laboratory measured flow rates were determined for emitters from three locations. Additionally, the effects of lateral orientation with respect to slope on emitter plugging was evaluated. Two different emitters were tested to evaluate slope effects on emitter plugging (type Y and Z). The emitters were alternately spliced together and installed in an up and down orientation on slopes of 0, 1, 2 and 4% and along the contour on slopes of 1 and 2%. The emitters were covered with soil and underwent a simulated year of dosing cycles, and then flushed with a flushing velocity of 0.6 m/s. Initial flow rates for the two emitter types were 2.38 L/hr with a C.V. of 0.07. There was no significant difference in flow rates among slopes for type Y emitters, but there was a significant difference between the 1% and 2 % contour slopes for type Z emitters. Application uniformity of three different laterals at each site was evaluated. Sections of the lateral from the beginning, middle and end were excavated and emission volumes were recorded for each emitter. Application uniformity of laterals ranged from 48.69 to 9.49%, 83.55 to 72.60%, and 44.41 to 0% for sites A, B, and C, respectively. Mean emitter flow rate was 2.21, 2.24, and 2.56 L/hr for sites A, B, and C, respectively under laboratory conditions. Application uniformity under laboratory conditions ranged from 70.97 to 14.91%, 86.67 to 79.99%, and 85.04 to 0.00% for sites A, B, and C, respectively. A flushing velocity of 0.15 m/s with no chlorination, shock chlorination of 3400 mg/L and flushing velocity of 0.15 m/s, and shock chlorination of 3400 mg/L and flushing velocity of 0.6 m/s treatment regiments were applied to all laterals collected to assess emitter flow rate recovery to the nominal flow rate published by the manufacturer. All laterals showed an increase in the number of emitters within 10% of the published nominal flow rate.

Devido à crise que o setor sucroenergético vem sofrendo ultimamente, mediante baixas nas cotações de açúcar e etanol nos mercados internacionais, a técnica de irrigação em cana-de-açúcar vem passando por alguns questionamentos quanto a viabilidade de implantação dos sistemas. Diante disso, novos sistemas de irrigação vêm surgindo no meio sucroenergético em busca da redução de perdas de água por evaporação e lixiviação e, também buscando uma maior longevidade de canaviais a fim de obter maior lucro líquido ao longo da vida útil da lavoura. A exemplo disso tem-se o sistema de gotejamento subsuperficial já bastante difundido na Austrália. Outro aspecto é a aplicação de vinhaça em cana-de-açúcar, cuja técnica vem sendo adotada há muito tempo visto que promove melhorias nas condições físico-química do solo além de promover economias com redução da aplicação de fertilizantes minerais visto que a vinhaça é rica no nutriente potássio. Diante disso, buscouse conduzir uma pesquisa sobre fertirrigação com aplicação de vinhaça e adubação mineral, em diferentes doses, via gotejamento subsuperficial em um Argissolo vermelho-amarelo com a variedade de cana-de-açúcar CTC15, buscando verificar os seus efeitos na produtividade da variedade e parâmetros biométricos, visto que, irrigação por gotejamento subsupercial em cana-de-açúcar é uma tecnologia relativamente nova para cultura no Brasil. Portanto, foi instalado um experimento de campo em área de aproximadamente 1600 m2, composto por 6 tratamentos compostos de diferentes doses de vinhaça, adubação mineral e sequeiro, e 4 repetições, em delineamento inteiramente casualizado, conduzidos por duas safras de cana (2013-2014 e 2014-2015), sendo o T1 sem irrigação e com adubação convencional junto ao plantio, T2 fertirrigado convencionalmente, T3 ½ DoseCETESB, T4 dose calculada a partir dos critérios da norma P4.231/2015 (DoseCETESB), T5 2xDoseCETESB e T6 3xDoseCETESB. O manejo da irrigação foi realizado por tensiômetros instalados em profundidades de 20, 40 e 60 cm. Os parâmetros avaliados foram: biometria completa da parte aérea (altura de planta, comprimento de limbo foliar, largura de limbo foliar, distância entre internódios, número de colmos, diâmetro de colmos, número de folhas e de perfilhos, clorofila a, b e total), produção por área e avaliação tecnológica (Brix, Pureza, Fibra, Cinzas e ATR). Os parâmetros foram avaliados por análise estatística de variância e teste de comparação entre médias por Tukey a 5% de probabilidade. Diante dos resultados obtidos, comparado à condição de sequeiro (T1), a irrigação exercida no ciclo da cana planta promoveu ganhos em número de perfilhos da ordem de 16%, número de colmos na ordem de 10% e largura de limbo foliar em 15%. A fertirrigação com vinhaça no ciclo de primeira soca, em comparação ao sequeiro (T1), promoveu ganhos de 13% para altura de plantas, 5% para comprimento de folhas, 12% para número de perfilhos e 4% para largura de limbo foliar. E não foram encontradas diferenças estatísticas para clorofila a, b e total e nem para parâmetros tecnológicos nos dois ciclos. O tratamento que melhor respondeu a fertirrigação com vinhaça em produtividade foi T4 (DoseCETESB) obtendo um valor de 190 ton ha-1. / Due to low sugar and ethanol prices in international markets, questions have arisen about the economic feasibility of implementing new irrigation techniques. Consequently, irrigation systems with reduced leaching and evaporative water loss, and with greater longevity, are being developed to achieve higher net income for sugarcane. The use of subsurface drip is already widespread in Australia, for example. One such management technique is the use of vinasse in sugarcane crops in Brazil. Vinasse has a long history of use in sugarcane production in Brazil, since it promotes improvements in the physical-chemical conditions of the soil and reduces the use of mineral fertilizers, as it is rich the potassium. This research relates to subsurface drip fertigation of the CTC15 variety of sugarcane in a redyellow Argisol, with vinasse and mineral fertilizer. The objective was to characterize the effect of fertigation on yield and several biometric parameters, since subsurface drip irrigation/fertigation is a relatively new technology for sugarcane production in Brazil. A drip irrigation system was installed in a 1600 m2 field, consisting of 4 replications of 6 treatments with different vinasse doses, mineral fertilizer and rainfed conditions, in a completely randomized design. The treatments were T1: No irrigation and conventional fertilization at planting, T2: fertigation at conventional fertilizer levels, T3: fertigation at ½ the standard P4.231/2015 CETESB rate, T4: fertigation at the standard CETESB rate, T5: fertigation at twice the CETESB rate and T6: fertigation at three times the CETESB rate. Data were collected for the 2013-2014 and 2014-2015 sugarcane crops. Irrigation was scheduled based on the moisture content in tensiometers installed at 20, 40 and 60 cm depth. The parameters evaluated were complete shoot biometrics (plant height, leaf blade length, width of leaf blade, the distance between internodes, number of stems, stalk diameter, number of leaves and tillers, chlorophyll a, b and total chlorophyll), crop yield, and sugarcane quality (Brix, Purity, Fiber, Embers and ATR). The parameters were evaluated by statistical analyses of variances, and comparison test of means by Tukey at 5% probability. Based on these results, compared to rainfed condition (T1), irrigation improved tiller number by 16 %, culm number by 10%, and width of leaf blade at 15%. The fertigation with vinasse in the first ratoon cycle, improved plant height by 13%, sheet length by 5%, number of tillers by 12%, and width of leaf blade by 4%. There were no statistical differences in chlorophyll A, chlorophyll B, total chlorophyll and sugarcane quality in either of the two crop cycles. The T4 treatment, fertigation at the standard CETESB rate, had the best yield response to fertigation with vinasse (190 ton ha-1).

Orientador: Edson Eiji Matsura / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-20T08:31:34Z (GMT). No. of bitstreams: 1 Elaiuy_MarceloLeiteConde_M.pdf: 2524526 bytes, checksum: 84d50a1f8818194cd8b6d4600d61a6be (MD5) Previous issue date: 2012 / Resumo: O uso de efluente de esgoto tratado (EET) na agricultura combinado com o método de irrigação por gotejamento subsuperfical (IGS) pode reduzir os custos de produção agrícola, fertirrigando de maneira eficiente as culturas. O conhecimento da dinâmica da água e do soluto no solo ao redor do gotejador contribui para o dimensionamento da IGS. Neste estudo, comparou-se as dimensões do bulbo úmido formado pela aplicação de EET e água de abastecimento municipal (AAM) em um Latossolo Vermelho distroférrico, para verificar o efeito da qualidade da água e da vazão entre gotejadores utilizados na cultura da cana-de-açúcar. O experimento de campo foi conduzido na Faculdade de Engenharia Agrícola da Unicamp aonde foram instaladas sondas de TDR, utilizadas para estimar a distribuição do conteúdo de água no solo e a condutividade elétrica (CE). Três trincheiras foram abertas e as sondas foram dispostas a 0,15; 0,25; 0,35; 0,45; 0,55 e 0,65 m de profundidade, e a 0,05; 0,15; 0,25 e 0,35 m de distância do gotejador, totalizando 21 sondas em malha por trincheira. Em duas paredes opostas de cada trincheira utilizou-se um gotejador enterrado a 0,30 m para cada uma das vazões constantes, 1,0 L h-1 e 1,6 L h-1. O volume molhado no solo foi observado ao longo do tempo em cada aplicação de 1,0 L de AAM, totalizando 10 aplicações. Após um período de 15 dias foi adotada a mesma metodologia de aplicação, e observado o volume molhado no solo com EET. Os resultados dos diferentes perfis de umidade do solo mostraram que as dimensões vertical e horizontal do bulbo úmido são similares para a AAM e para o EET, sendo peculiares de acordo com as vazões utilizadas e volume aplicado. Observou-se também para o EET uma maior concentração de soluto próximo ao gotejador decaindo progressivamente com a frente de molhamento / Abstract: The use of treated sewage effluent (TSE) in agricultural combined with the subsurface drip irrigation (SDI) method may decrease the costs in agricultural production, in attempts to fertigate crops more efficiently. The precise knowledge about the dynamic of water and solute in the soil around the emitters contribute for a proper design of SDI. In this study, we compared the dimensions of the wet bulb formed by the application of TSE and municipal water supply (MWS) in a dusk red latosol, to evaluate the effect of water quality and discharge between drippers, used in sugar cane crop. The field experiment was conducted at the College of Agricultural and Engineering/State University of Campinas, where TDR probes were used to monitor the distribution of soil water content and electrical conductivity (EC). Three trenches were opened and 21 three-rod TDR probes were installed, placed at 0.15, 0.25, 0.35, 0.45, 0.55 and 0.65 m - in depth, and 0.05, 0.15, 0.25 and 0.35 m - distance from the dripper, totaling 21 probes in mesh per trench. In two opposite walls of each trench this procedure was replicated using a dripper buried at 0.30 m for each constant discharge of 1.0 L h-1 and 1.6 L h-1. The wetted soil volume was observed over time in each application with 1 L of MWS, totaling 10 applications. After a period of 15 days, was adopted the same methodology of application and the wetted soil volume was observed with TSE. The results from different wetted soil profiles indicated that dimensions vertical and horizontal of the wet bulb are similar for the MWS and TSE, being peculiars according to the discharges used and volume applied. We also observed for the TSE greater solute concentration near the emitter decreasing progressively towards the wetting front / Mestrado / Agua e Solo / Mestre em Engenharia Agrícola

A major design issue in the implementation of a Subsurface Drip Irrigation (SDI) system for extensively crops such as alfalfa (i.e. crops that cover the entire surface as opposed to row crops), is the determination of the appropriate depth of placement of the drip line tubing. It is important to allow necessary farming operations with heavy equipment at harvesting times while still providing adequate water to meet the crop water requirements. It is also a need to ensure appropriate spacing between the dripline laterals to assure reasonable lateral irrigation uniformity for plant germination. In this study, the program HYDRUS-2D was used to determine the wetting pattern above and laterally from a subsurface drip emitter of an SDI system, for three soils typically found in Southern California and Arizona, a Sandy Clay Loam (SCL), a Clay Loam (CL) and a Loam (L). The design and management conditions from an experimental alfalfa field with an SDI system located at Holtville CA were used and analyzed. The first irrigation design was with a drip line depth of placement of 30 cm and the second design with an installation depth of 50 cm. The two different irrigation management schemes utilized by the farmers and producers in that area were: one with a running time of six hours and a frequency of every three days and the second one with an irrigation running time of twenty-four hours with a frequency of seven days or irrigation every week. After having carried out the analysis and studies of the irrigation designs and management schemes mentioned above, a new model with its corresponding management was proposed to meet the alfalfa water requirements under that particular field and weather conditions while we ensure a sufficiently dry soil surface at harvesting time for each soil case. This irrigation management includes twelve hours or irrigation every three days, for each of the three soils analyzed. It was found that the vertical rise of water above the emitters on the day of the cut, for our recommended SDI management was 26 cm, 29 cm, and 27 cm, with a moisture content at the soil surface of 14.9%, 24%, and 13% for the SCL, CL, and L soils respectively. Then, through the utilization of classical soil mechanics theory, an analysis to calculate the increase in stress on soils at any depth due to a load on the surface from a conventional tractor used during harvest operations was made for the proposed SDI system. The results from the increase in stress were then used together with soil strength properties such as shear strength as a function of soil moisture content to determine the minimum allowable depth of placement of the drip line tubing to ensure that soil failure does not occur. The load increase from a 3,300-kg four-wheel tractor was found to be 0.59 kg/cm2 under a rear tire at 10 cm below the surface and 0.07 kg/cm2 at 70 cm below the surface. To ensure that shearing failure does not occur, a stress analysis using Mohr’s circle indicated that the soil moisture content at 10 cm below the surface should be no greater than 26.8%, 32.7%, and 27% in the SCL, CL, and L soils respectively. The mimimum moisture content of 26.8% occur at 10 cm above the drip line for a SCL soil, which means that the minimum depth placement to avoid failure would be 40 cm below the surface. A similar analysis for the CL and L yielded minimum installation depths of 35 cm and 40 cm respectively. This type of analysis is useful in determining the depth of placement of SDI drip line tubing to ensure adequate trafficability of soil irrigated with subsurface drip irrigation systems. An additional outcome of the modeling study was the determination of the lateral extent of the wetted zone which can be used to determine the appropriate lateral spacing between drip line tubing. Thus, to ensure adequate spatial coverage by a subsurface drip system, the maximum horizontal spacing should be of 80 cm for SCL and L soils and 90 cm in CL soils.