Improving water efficiency is and will continue to be a top concern to meet the world food production demands for a growing population. By having a clear understanding of water efficiencies, communities will be able to address these concerns from an economic standpoint and use more productive methods to grow food and limit water consumption. This study examines the water efficiencies of three irrigation methods over a single growing season in southeastern Oklahoma. Two crops, tomatoes and cucumbers, were grown using drip irrigation, a self-wicking container, and a non-circulating hydroponics barrel. Results at the end of the season showed the drip irrigation method had the highest water efficiency in terms of yield of product over water applied for both crops. The drip irrigation method also had the lowest associated set up costs and second lowest time requirements after the hydroponics method. These results were found to be consistent with other studies that compared drip irrigation to other irrigation methods and showed drip to have the highest water efficiencies.

Thesis (Ph.D. (Agricultural Economics)) -- University of Limpopo, 2015 / Various types of management practices/institutional arrangements of the irrigation schemes exist in the world. According to the principles delineated in literatures, these irrigation schemes are categorized in terms of their management practices. The study was designed to compare the level of technical efficiency of farmers at different management practices of the irrigation schemes (i.e. integrated, specialised and multipurpose water management practices of the irrigation schemes) in Limpopo Province. Data were collected using a structured questionnaire which was administered on 200 farmers at different irrigation schemes. Stochastic frontier production function of Cobb-Douglas type was employed to analyse the data and thereby ascertain the level of technical efficiency and its determinants. The results indicated the mean technical efficiency of 0.74, 0.72 and 0.76 for the integrated, specialised and multipurpose water management practices of the irrigation schemes respectively which implied that, there is a greater scope to increase maize, tomato, onion and spinach production with the current technology and resources available at the irrigation schemes. The most important contributors in maize, tomato, onion and spinach production efficiencies were seed, fertilizer, capital and land. Thus an appropriate amount of seed, fertilizer, capital and land could increase the productivity of maize, tomato, onion and spinach. The results further revealed that education level of farmers, age of the farmers and land size were negatively significant toward the technical inefficiency of farmers at different irrigation schemes, which imply that an increase in any of the three variables will reduce the inefficiency and enhance the efficiency. While the family size of the farmer was positively significant, which implies that the bigger the family size, the higher the inefficiency farmers would become for the production of maize, tomato, onion and spinach. Gender and income level of the farmers at different irrigation schemes were revealed to be insignificant toward the inefficiency. The institutional arrangements or the management practice of the irrigation schemes showed slight differences in affecting the efficiency of farmers at different irrigation schemes. Policies designed to educate famers at different irrigation schemes through proper agricultural extension services could have a great impact in increasing the level of efficiency and hence maize, tomato, onion and spinach productivities. The Department of Agriculture should allocate more funds to strengthening the extension directorate and expanding the delivery of extension services to farmers at different irrigation schemes. Irrigation schemes were established in order to insure food security, alleviate poverty, job creation, among others. Therefore, it is of paramount importance for the government of South Africa in collaboration with the private sector to revitalise the irrigation schemes in Limpopo Province irrespective of the institutional arrangements. It is of vital concern for the policy makers to focus on the benefits of economies of scale in agricultural farming system. Therefore, land size should be increased for the farmers in integrated water management practice of the irrigation schemes to an optimum level in order for them to improve the level of technical efficiency.

Call number: LD2668 .T4 1979 B59 / Master of Science

5 pp. / This Extension Bulletin is similar to others previously completed for Tucson, Phoenix, Flagstaff, Prescott and Payson. The bulletin provides information on turfgrass consumptive use for the River Cities (Bullhead, Lake Havasu, etc.) and Kingman areas. Consumptive use is provided for each month of the year in units of inches/month and inches/day for three grass production systems: high quality overseeded turf, acceptable quality overseeded turf and acceptable quality turf with no overseeding. The bulletin concludes with a discussion on how to use incorporate this into turf irrigation management programs.

3 pp. / Determining the Amount of Irrigation Water Applied to a Field (AZ1157) / Critical to any irrigation management approach is an accurate estimate of the amount of water applied to a field. Too little water causes unnecessary water stress and can result in yield reductions. Too much water can cause water logging, leaching, and may also result in loss of yield. This publication discusses how to set the water amount and the time period, when taking the system's efficiency into consideration.

3 pp.

3 pp. / Critical to any irrigation management approach is an accurate estimate of the amount of water applied to a field. Too little water causes unnecessary water stress and can result in yield reductions. Too much water can cause water logging, leaching, and may also result in loss of yield. This publication discusses how to set the water amount and the time period, when taking the system's efficiency into consideration.

Revised; Originally Published: 2006 / 3 pp.

[Abstract]: Sugarcane farmers in Bundaberg have had limited access to irrigation water over the last ten years. The district has the potential of growing 3.8 million tonnes of sugarcane. However, a series of dry seasons saw this reduce to 2.1 million tonnes in 2002. Compounding the effects of both dry seasons and limited water supplies has been a 30% reduction in the sugar price over this period. The irrigation requirement of sugarcane in the Bundaberg area is 8 ML/ha. The original allocated volume for sugarcane production in this area was 4.5 ML/ha (based on 1970 production areas). However, as the area under production has increased and announced allocations in each year has reduced, this allocation is now equivalent to an application volume of about 2 ML/ha A change from the traditional practice of full irrigation is required as water supplies become depleted. As there were no clear guidelines on how growers could respond to diminishing water supplies, this research investigated opportunities to fine tune irrigation practices and the performance of irrigation systems (ie. low cost solutions) that would assist growers to maximise sugarcane yield. A grower survey was initially conducted to identify current practice and opportunities for change. Field investigations focused on the performance of water winch and furrow irrigation systems, which make up 91% of the irrigated area in the district. As most of these application systems have insufficient capacity to meet crop demands opportunities to schedule irrigations were limited to start up after rain. Improvements in irrigation system performance were found to provide the greatest potential to increase sugarcane yield under conditions of limited water. Investigations identified that irrigation performance could be significantly improved through relatively minor adjustment. Field trials found that wind speed and direction significantly influenced the performance of travelling gun irrigators. Although growers were generally aware of the effects of wind, meteorological data suggested that the opportunity to operate water winches in low wind conditions is limited. Changing to a taper nozzle under moderate to high wind conditions will reduce the effect of wind on performance. This practice was found to improve the uniformity (measured by Christiansen’s Uniformity Coefficient, CU) by 16%. The grower survey indicated that there was no preference towards the use of taper nozzles in windy conditions. Additional trial work developed a relationship between the variation in water applied to the field through non uniformity and sugarcane yield. An 8% reduction in yield was determined for a 10% reduction in CU. This indicated that changing to a taper nozzle could potentially increase sugarcane yield by 15% in high wind conditions. Other settings, which also influenced uniformity, included lane spacing and gun arc angle Simple changes to the operation of furrow irrigation systems were also found to dramatically improve irrigation performance. Field measurements in combination with simulation modelling of irrigation events using SIRMOD II identified that current irrigation performance ranged in application efficiency from 45 to 99% (mean of 79%) and a distribution uniformity from 71 to 93% (mean of 82%). Both application efficiency and distribution uniformity were increased to greater than 90% and 84% respectively, except on a cracking clay soil. Improvements in application efficiency and distribution uniformity were achieved by adjusting furrow flow rate (cup size), turning the irrigation off at the right time (ie. just as it reached the end of the field) and banking the end of the field. Growers had a good understanding of the correct cut off time and were attentive to reducing run off through either banking ends or tail water return. However, growers had a poor understanding of the significance of furrow flow rate. Other opportunities to improve irrigation performance on high infiltration soils included alternate furrow irrigation and shallow cultivation practices which maintained compaction in the interspace and reduced infiltration. Soil moisture and crop growth measurements indicated that sugarcane yield could be maximised by starting the irrigation rotation earlier after rainfall (ie. at a deficit equal to the irrigation amount). These observations were modelled using the crop simulation model APSIM sugar to assess the strategy over a longer time interval and the influence of seasonal variation. Simulation modelling showed that final sugarcane yields were not sensitive to irrigation start-up strategies. Yields for the start-up strategies modelled varied by less than 5 tc/ha. This minor difference occurred as the crop yield was driven by the total amount of water available to the plant. The limited amount of irrigation water available to the plant (2 to 3 ML/ha) had only a minor effect on the water balance and no significant change to effective rainfall between strategies. The greatest difference in yield occurred between irrigation treatments when water was left over at the end of the season (9.2 tc/ha). Starting irrigation earlier after rainfall events (on a 14 day rotation) provided the greatest opportunity to use all of the available irrigation supply. By comparison, delaying the application of the first irrigation after rainfall resulted in some of the irrigation water not being applied in 30% of years.

Texte remanié de: Th. doct.--Ethnol.--Paris 10, 1996. Titre de soutenance : Antagonismes et irrigation, organisation sociale d'une communauté paysanne du Nord-Ouest du Portugal. / Bibliogr. p. 245-263. Index.