Thesis (Ing.)--Universidad Mayor de San Andrés, Facultad de Agronomía, Carrera de Ingeniería Agronómico, 2004. / Reproduced from copy at BYU's Benson Institute. Includes bibliographical references (leaves 101-106).

Thesis (Ing.)--Universidad Técnica del Norte, Facultad de Ingeniería en Ciencias Agropecuarias y Ambientales, Escuela de Ingeniería Agroindustrial, 2003. / Reproduced from copy at BYU's Benson Institute. Includes bibliographical references (leaves 84-86).

Field experiments to compare absorption of nutrients by cotton plant (Gossvpium hirsutum L. Var. Deltapine 62) and their distribution in soil under surface and subsurface drip systems were conducted in 1984 and 1985 at the Campus Agricultural Center, University of Arizona in Agua fine sandy loam soil (Typic Torriflvents). The mixed fertilizer solution with labeled nitrogen-source was injected into surface and subsurface drip treatments in equal amounts. There were no significant differences among surface and subsurface drip treatments detected with respect to total nitrogen, phosphorus, potassium and zinc uptake by plants because of equal availability of nitrogen under both drip systems and sufficient initial levels of the other nutrients were found in this soil. Fertilizer application significantly increased total nitrogen, phosphorus, potassium and zinc uptake by cotton plants because N promoted more vegetative growth and therefore more dry matter production was obtained. Under all drip treatments and both labeled nitrogen sources, plants growing on unfertilized rows absorbed nitrogen-15 fertilizer mainly because of the extension of roots and some lateral movement of nitrate to the unfertilized rows. Significant differencs among surface and subsurface drip treatments were not detected with respect to absorption of nitrogen-15 and percentage of fertilizer nitrogen in plants. Consistent differences among ammonium (N-16) and nitrate (N-15) labeled sources were not observed with respect to percentage of fertilizer nitrogen in plants. The plant recovery of applied nitrogen was higher with the difference method than with the tracer method because the nitrogen fertilizer produced effects in the soil or on the ability of the plants to obtain soil nitrogen that did not occur in the unfertilized rows. Consistent differences between drip treatments were not observed with respect to the final nitrate, ammonium, phosphorus, potassium, zinc levels and total soluble salts in the soil horizontally or vertically. The range of the residual fertilizer nitrogen in the soil after the first growing season was 7 to 28%.

No description available.

Cotton (Gossypium hirsutum L.) grown under drip irrigation was evaluated over a two year period for physiological and morphological responses. Three water levels representing, 103, 93 and 87% of estimated consumptive use (63.6 ha-cm) were used in Marana, AZ. in 1983. In 1984, cotton was grown under eight drip irrigation treatments corresponding to 120, 100, 80 and 60% of the estimated consumptive use (79.5 ha-cm) in Stanfield, AZ. These volumes of water were applied as small daily amounts and larger weekly amounts for a total of eight irrigation treatments. The experimental design was a randomized complete block with four replications. Mean leaf area ratio (LAR), leaf area index (LAI), mean net assimilation rate (NAR), mean relative growth rate (RGR), mean crop growth rate (CGR), plant height and the number of mainstem nodes were determined using the growth analysis method. Transpiration, diffusive resistance, leaf and ambient temperatures were measured with a steady state porometer. Apparent photosynthesis (APS) was determined in 1983 with an infrared gas analyzer which measured CO(,2) concentrations. In 1983, the cotton plants from the 103% irrigation treatment had greater transpiration, lower diffusive resistance and lower APS than the 93% treatment plants. In 1984, no significant differences were observed between the seasonal transpiration rates from the eight irrigation treatments. Cotton plants grown under the 120% treatment showed superior diffusive resistance responses than those from the 60% treatment. Temperature differentials were higher in the 120% treatments than in the 60% treatments. No significant differences were found between LAR, NAR, RGR and CGR during 1983 and 1984. Even though there were no differences between the total number of flowers produced in the three treatments in 1983, the 93 and 87% treatment plants produced more seed cotton than the 103% treatment plants. In 1984, the seed cotton yield from the 60% daily treatment was significantly the lowest. Due to the problems related to the late initiation of treatments and excessive rainfall, the physiological and morphological responses of cotton were inconsistent across the various water levels in 1983. Regression analysis confirmed the erratic responses of cotton plants from the weekly treatments across the wide range of environmental conditions in 1984.

Studies were conducted on commercial farms in 1982 and 1983 to study the effects of above surface drip irrigation, below surface drip irrigation, and furrow irrigation on flowering, boll set, yield, and growth of cotton (Gossypium hirsutum L.). Two varieties were used in 1982, 'Deltapine 62' and 'Deltapine 90', using both above and below ground drip irrigation and Deltapine 90 was grown under furrow irrigation. In 1983 the study was conducted at a different location with above ground drip irrigation and furrow irrigation using the cotton variety 'Deltapine 41'. The irrigation water was monitored to deliver 100% of consumptive use (CU), 85% of CU, 70% of CU, 100% of CU every other day and CU which was the grower's estimate of consumptive use. All open flowers were tagged using Kwik-Lok labels dated with the day the flower opened. Tagging of flowers started from first open flower and continued for 17 weeks in 1982 and 15 weeks in 1983. Plants were sampled twice in 1982 and three times in 1983 for LAI and partitioning studies. All open bolls were harvested on a weekly basis for a total of 12 harvests. In the 1982 experiments no statistical analyses were made because the five treatments were grown in different fields and could not be randomized together. A general comparison showed that Treatment 1, Deltapine 62 above ground drip system produced the highest number of flowers but it had the lowest percent of boll set. Treatment 5, Deltapine 90, furrow system, produced the lowest number of flowers but it had the highest percent of boll set. Treatment 3, Deltapine 62 below ground drip system, had the highest boll set and Treatment 5 retained the least number of bolls. Treatment 2, Deltapine 90 above ground dry system, had the highest seed cotton yield and Treatment 5 had the lowest yield. In the 1983 experiment, there were no significant differences in flowering, boll set, or yield among the five irrigated treatments. The furrow treatment could not be compared statistically with validity with the drip treatment because it was grown in a different field but a general comparison showed that it produced the lowest number of flowers and seed cotton yield although it had the highest percent of boll set.

Experiments were conducted with 180 m long T-tape and Agrifim emitter lateral lines in the laboratory and field to determine the effects of water temperature and sediment concentration on the hydraulics of drip irrigation laterals. The flow regime was laminar through the T-tape emitter and turbulent through the Agrifim emitter. Water temperature decreased along the lateral line in the laboratory where the inlet water temperature was higher than ambient air. In contrast, temperatures increased along a lateral line exposed to the sun in the field with an inlet temperature lower or slightly higher than that of air. The rate of increase or decrease was more pronounced towards the end of the line. The effect of temperature was highly significant on emitter flow rates obtained for a T-tape emitter as opposed to those recorded for the Agrifim emitter in the laboratory; however, the increase of emitter flow rates due to temperature was reduced by plugging in the field. Discharges of T-tape emitters were dominated by the hydraulic pressure for the first half of the line with the water temperature being more important for the second half of the line in both the laboratory and field. Measured discharges of Agrifim emitters were dominated by the hydraulic pressure for the entire lateral length especially in the laboratory. The Darcy-Weisbach friction factor, as opposed to the Blasius friction factor, is recommended for design because it accounts for the wall roughness of the pipe. The Hazen-Williams roughness coefficient was related to Reynolds number to improve the drip system design. Total friction losses, as a result of water viscosity changes and lateral discharge variations due to temperature, increased significantly for the T-tape emitter lateral in the laboratory and field for different inlet water temperatures and inlet-outlet temperature variations. In contrast, total friction losses decreased for the Agrifim emitter lateral primarily because of water viscosity changes with temperature. The sediment concentration along an Agrifim emitter lateral in the laboratory decreased sharply in the second half of the line when the flow velocity dropped below 0.29 ms⁻¹ . Also friction losses increased for an Agrifim emitter lateral in the laboratory as the inlet concentration increased from 200 to 650 mg/l.

No description available.

Dissertation (Ph.D.)--Auburn University, 2009. / Abstract. Includes bibliographic references (p.140-163).

No description available.