Nitrate leaching from research and commercial potato rotations was evaluated using stainless steel zero tension lysimeters, tile drainage and soil samples. The effect of nutrient management versus conventional fertility on marketable potato yield was also investigated. Neither the lysimeters nor the tile lines were able to detect a significant treatment effect on the concentration of NO3--N in collected water samples. However, trends in the NO3--N concentration conformed to nutrient application. Soil samples detected similar trends in soil NO3--N at the research site. Nutrient management fertility had no significant effect on marketable potato yield or soil NO3--N at the commercial sites. A significant crop effect on soil NO3--N was detected. Fall soil samples indicated excess NO3--N in the soil following potato harvest suggesting an overuse of nitrogen fertilizer.

Thesis (M.S. - Watershed Management)--University of Arizona. / Includes bibliographical references.

No description available.

Excess nitrate-N concentration (>10 mg L-1) in drinking water can cause significant risk to human health. Also, at very low concentration (0.035-0.1 mg P L-1), phosphorus is considered as a pollutant due to its effects of promoting algal growth and eutrophication of surface waters. This thesis’ research was conducted at two different sites. The first study was conducted at Carman on a sandy loam soil with cropping system, perennial versus annual, as the main plot and manure nutrient management system, as the subplot to measure nitrate and phosphorus leaching from hog manures. The second field experiment, located northwest of the town of Carberry, Manitoba, was conducted on a loamy sand soil. A two year rotation was employed for the annual cropping systems with a randomized complete block design. Treatments included two rates of liquid hog manure (LH-5000, LH-2500), two rates of fertilizers (F5000, F2500) corresponding to the amount of available nitrogen in the two rates of hog manure a compost treatment (Com-2500) and a control for a total of six treatments. The results from Carman site showed that while a substantial amount of nitrate-nitrogen was lost from the annual plots (40 to 60 kg ha-1 in 2010 and 23 to 60 kg ha-1 in 2011), a negligible amounts of nitrate was lost from the perennial (< 1 kg ha-1). There was no evidence of significant downward movement of phosphorus below the top 15 cm soil layer in this study. However, repeated, annual application of manure at an N-based rate resulted in increased soil test P. In Carberry, total N leaching of fertilizer amended plots was greater than in plots that received manure. Based on the results, application of liquid hog manure at the rate of 2500 gallon ac-1 was economically and environmentally more desirable and is recommended. We applied the multi-layer water balance model, VSMB, to the data that we generated in the field to gain an understanding of how well the model will simulate the loss of water that we measured from the lysimeters. The simulation study showed that the VSMB model grossly underestimated the amount of leached water, possibly due to an overestimation of evapotranspiration. / October 2015

Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. Tarek Abichou, Florida State University, College of Engineering, Dept. of Civil and Environmental Engineering. Title and description from dissertation home page (viewed June 21, 2004). Includes bibliographical references.

O conhecimento da demanda hídrica de uma cultura é fundamental para o planejamento da implantação de novas áreas, bem como para a análise da viabilidade econômica de uma cultura em determinada região. A utilização de culturas para fontes de matéria prima alternativa vem sendo altamente estudada nos últimos anos. Dentre muitas, vem se destacando no cenário nacional e mundial a cultura do pinhão-manso (Jatropha curcas L.) para a produção de biodiesel. O consumo de água por parte do pinhão-manso é pouco conhecida, necessitando ser estudada a fim de aprofundar os conhecimentos sobre a cultura e fornecer parâmetros confiáveis para a prática da irrigação. Os objetivos desse trabalho foram determinar a evapotranspiração (ET), a evaporação (E), a transpiração (T), o coeficiente de cultivo (Kc), coeficiente de evaporação (Ke) e coeficiente de cultivo basal (Kcb) do pinhão-manso na fase de formação irrigados por pivô central, gotejamento e sem irrigação na cidade de Piracicaba, SP. O experimento foi realizado na Fazenda Areão da Escola Superior de Agricultura \"Luiz de Queiroz\" da USP durante o período de março de 2012 a abril de 2013. O experimento foi dividido em três tratamentos, sendo: irrigado por pivô central, gotejamento e sem irrigação. A determinação de ET foi realizada por meio lisímetros de pesagem em cada tratamento, contabilizando a variação de massa em função das entradas saídas de água no sistema. A determinação do Kc foi realizada pela razão entre ET e ETo (estimado a partir de dados coletados na estação meteorológicos automática da Fazenda Areão). Por meio de microlisímetros de pesagem, foi determinado E. De posso dos dados de E, foram determinados os valores de T pela diferença de E (determinado no microlisímetro) e ET (determinado no lisímetro). Os valores de Ke e Kcb foram determinados pela razão de E e T por ETo, respectivamente. Os valores de ET variaram, principalmente, em função do método de irrigação. Foi observado uma superioridade dos valores de ET para o tratamento irrigado por pivô central, seguido do tratamento irrigado por gotejamento e sem irrigação. As médias dos tratamentos durante o primeiro ano foram 3,17, 2,82 e 2,82 mm dia-1 para os tratamentos irrigado por pivô central, irrigado por gotejamento e sem irrigação, respectivamente. Essa mesma proporção de ET entre os tratamentos irrigados foi observado nos valores de Kc. A média do período de Kc foi 0,69 e 0,63 para os tratamentos irrigados por pivô central e gotejamento. Essas maiores taxas de ET e Kc do tratamento irrigado por pivô central em relação ao tratamento irrigado por gotejamento foi devido ao método de irrigação por gotejamento ser mais eficiente na utilização de água pelas plantas em relação ao método por pivô central. Nesse método, a água é aplicada de maneira localizada as plantas, diferentemente do método por pivô central, em que a água é aplicada em toda a superfície do solo. Isso faz com que as taxas de E no método por gotejamento seja menor em relação ao pivô central, diminuindo as taxas de ET. De maneira geral, as taxas de E e Ke foram maiores em relação aos valores de T e Kcb durante o período analisado. Isso foi devido as plantas estarem com porte baixo e o solo estar quase por completo exposto as variações atmosféricas, fazendo com que as taxas de E e Ke sejam superiores as de T e Kcb. A média de E e Ke foram 1,85 mm dia-1 e 1,03, respectivamente, e as médias de T e Kcb foram 0,4 mm dia-1 e 0,2, respectivamente. / The knowledge of the water demand of a culture is essential for planning of new areas, as well as for the economic viability analysis of a culture in a specific region. The use of crops for alternative feedstock sources has been extensively studied in the last years. Among many, jatropha (Jatropha curcas L.) has been highlighted for biodiesel production in the national and global scenarios. Water consumption by the jatropha is little known, which requires to be studied in order to increase the knowledge and provide reliable parameters for the irrigation practice. The objectives of this study were to determine the evapotranspiration (ET), evaporation (E), transpiration (T), crop coefficient (Kc), evaporation coefficient (Ke) and basal crop coefficient (Kcb) of jatropha in the formation phase irrigated by center pivot, drip and without irrigation in Piracicaba, SP. The experiment was conducted at Areão Farm of Escola Superior de Agricultura \"Luiz de Queiroz\" of USP during March 2012 to April 2013. The experiment included three treatments: center pivot irrigated, drip irrigated and dryland. The determination of ET was made by weighing lysimeters for each treatment, accounting the inputs and outputs of water in the lysimeter system. The determination of Kc was made by the ratio between ET and ETo (estimated from data collected at the automatic meteorological station of Areão Farm). The determination of E was made by microlysimeters and T was determined between the difference of ET and E. Ke and Kcb values were determined by the ratio of E and T by ETo, respectively. ET values varied, mainly, according to the irrigation method. It was observed superiority of ET values for the treatment irrigated by center pivot, followed by the treatment irrigated by drip and without irrigation. The average during the first year was 3.17, 2.82 and 2.82 mm day-1 for the treatment irrigated by center pivot, irrigated by drip irrigated and without irrigation, respectively. The same proportion of ET from irrigated treatments was observed in the values of Kc. In the period, the average of Kc was 0.69 and 0.63 for the treatments irrigated by center pivot and irrigated by drip. These higher rates of ET and Kc of the treatment irrigated by center pivot compared to the treatment irrigated by drip was due to the method of drip irrigation is more efficient in water use by plants in relation to the method irrigated by central pivot. In this method, the water application is made in a localized way, differently in relation to the center pivot method in which water is applied all over the soil surface. This makes E rates given by drip irrigation method lower than the center pivot irrigation method, decreasing its ET averages. In general, rates of E and Ke were higher compared T and Kcb values during the period analyzed. This was explained due the short plants stature and the soil was almost completely exposed to atmospheric variations, causing rates of E and Ke exceed from T and Kcb rates. The average of Ke and E were 1.85 mm day-1 and 1.03, respectively, and the average of T and Kcb were 0.4 mm day-1 and 0.2, respectively.

Increasing irrigation efficiency on turfgrass could help reduce water consumption on large turf facilities. Two experiments were conducted using perennial ryegrass (Lolium perenne (L.) Derby) to evaluate the potential of using remote sensing to estimate turf water status, predict daily evapotranspiration (ET), and estimate turf biomass. In the first experiment a crop water stress index, utilizing remotely sensed canopy temperature, were used to schedule irrigations on 6 of 10 drainage lysimeters. Three of the remaining lysimeters were irrigated used on meteorological estimates of ET calculated using a modified Penman equation. The results of this experiment were inconclusive due to inconsistent lysimeter drainage characteristics. The second experiment was conducted on a turf green with multiple heights to evaluate the potential for using canopy radiance to estimate turf biomass. These results showed that turf biomass could be estimated from a vegetative index (Red Ratio = Near Infrared/Red radiance) obtained through measurements of canopy radiance (r2 = 0.91).

Evapotranspiration rates (ET) and consumptive water use (CWU) were measured for three desert turfgrasses using weighing lysimeters with a calcined clay growth medium. Water use rates were compared over a two-year study for 'Sea Isle I' seashore paspalum (Paspalum vaginatum) and A138 desert saltgrass (Distichlis spicata), along with 'Tifway' bermudagrass (Cynodon dactylon x Cynodon transvaalensis). Saltgrass showed elevated leaf canopy temperatures for extended periods before exhibiting visible wilt symptoms while 'Tifway' bermudagrass and seashore paspalum wilted readily, even at relatively high soil water contents. Saltgrass transpired for 11.9 d on average before drought stress was observed. Seashore paspalum maintained leaf turgor, on average 5.6 d without irrigation, whereas 'Tifway' bermudagrass averaged 4.0 d before requiring irrigation. The two-year average Kc values for three grasses before self-imposed drought was expressed by visible leaf wilting were 0.85, 0.79, and 0.74, for A138 saltgrass, 'Sea Isle I' seashore paspalum, and 'Tifway' bermudagrass, respectively.

A better understanding of the hydrogeology of mine waste rock and cover systems is essential for the quantification, prediction and reduction of metals loading to the receiving environment. A series of experiments were conducted on an instrumented intermediate-scale waste rock pile at the Cluff Lake Mine in Saskatchewan to investigate the changes in flow and solute transport within coarse waste rock under three different surface conditions. Following these studies, the waste rock pile was deconstructed, structures were mapped, and samples were collected for physical characterization and pore water extraction. The internal structure of the waste rock pile was more important than the texture and topography under the free-dumped and ripped/leveled surface, while the surface condition was found to be the dominant control on spatial and temporal variability of outflow from the waste rock with the covered surface. Data from a deuterium tracer test, lysimeter outflow, and from TDR probes were used to derive estimates of the maximum and an average pore water velocity through the uncovered and the covered waste rock. An average pore water velocity through the matrix materials of the uncovered waste rock was approximately 1.5 m/yr and maximum preferential flow velocities were as high as 5 m/day. The post-cover pressure wave velocity of 0.1 to 1 m/day is inferred from outflow and TDR data, and average pore water velocities (0.39 m/y and 0.73 m/y) are calculated by the water flux and tracer methods, respectively. The distribution of the tracers in pore water and the internal structure were mapped during a detailed deconstruction of the waste rock pile and attempts were made to link the data to the spatial and temporal patterns of lysimeter outflow. The pore water chloride concentrations and the deuterium values did not provide conclusive data necessary to link the spatial and temporal patterns observed in the lysimeter hydrographs to internal structure; however, it provided insight into the internal flow mechanisms and water residence times.