Performance Of Drip Irrigation System Research Articles

English

The study aimed to evaluate the performance of drip irrigation systems with clean water application and cassava wastewater processing, by determining the distribution uniformity coefficient (CUD) and the process capability index (Cpl). The research was carried out in an agroindustrial area from western Parana State, Brazil, where two irrigation systems were set and operated in different periods. After the essays implementation, the two irrigation systems were identified and stored in order to be retested after one year (2nd year of collection). So, the same conditions that were established in the first year had still been considered. Treatments with effluent showed flow averages near to those ones obtained with the use of clean water. Only in the T4 treatment, CUD was classified as good, while the others were excellent. The process was rated as efficient only in T1 with 80% LCL, with a 2.04 Cpl. Thus, based on this technique, it was possible to check that the system is able to keep suitable levels of uniformity. Key words: Distribution uniformity, process capability, water quality.

Making the user visible: analysing irrigation practices and farmers’ logic to explain actual drip irrigation performance

The actual performance of drip irrigation (irrigation efficiency, distribution uniformity) in the field is often quite different from that obtained in experimental stations. We developed an approach to explain the actual irrigation performance of drip irrigation systems by linking measured performances to farmers’ irrigation practices, and these practices to the underlying logic of farmers who operate these systems. This approach was applied to 22 farms in Morocco. Four sets of variables helped explain the gap between the actual irrigation performance and the performance obtained in experimental conditions: (1) farmers have agro-economic motivations or want to improve their social status, and for them, irrigation performance is at best an intermediate objective. (2) Irrigation performance is not a static value, but a rapidly evolving process, related to the (perceived) ability of farmers to change irrigation practices and renew irrigation equipment, but also to farmers’ aspirations. (3) The social network of farmers, supporting the introduction and use of drip irrigation, determines how farmers may share experience, information and know-how related to drip irrigation. (4) Today, there is no social pressure to irrigate carefully to save water; only the state explicitly links the use of drip irrigation to saving water. Making the drip user visible in research and policy studies would lead to more realistic assessments of irrigation performance and draw the attention of policy makers to the actual conditions in which drip irrigation is used, and as a consequence help incorporate ‘saving water’ as an objective for drip irrigation users.

점적관개 시설의 관개균일도 및 성능 평가

Drip irrigation is a affordable irrigation under structured cultivation. Drip irrigation system with high uniformity can be achieved through effective design, maintenance and management of irrigation systems. Nevertheless the design guidelines have not been established for the drip irrigation system products in domestic and imported considering cultivation method and greenhouse environment in Korea. The objectives of this study were to evaluate the performance of drip irrigation system with uniformity through an experiment. The experiment was conducted to study with nine different types of emitters produced in domestic and imported. Hazen-Williams coefficients were also estimated for the drip emitter through hydraulic simulation for design use. It was found that approximately 91.5 % for 10 cm emitter spacing and 96.2 % for 30 cm emitter spacing of statistical uniformity were observed in respectively. Average emission uniformity was decreased as the reduction of emitter spacing. The results would be used in the drip irrigation system design and guideline construction.

Hydraulic Performance of Drip Irrigation System with Municipal Wastewater

Generation of wastewater in huge amounts is putting a lot of pressure on irrigation engineers for its safe disposal or reuse in agriculture. Though wastewater could contribute to major and minor nutritional requirement of crops, but the presence of microbial contaminants and toxic elements limits its use. Utilization of wastewater for irrigation through drip irrigation system seems to be a good choice to reduce the chances of contamination due to restricted quantity of water application. Since clogging in such a situation would be the main problem, its remediation is required for enhanced utilization of wastewater through drip irrigation system. Physical and chemical characteristics of wastewater were determined and compared with ground water. While higher EC, pH, Mg, and carbonate were observed in ground water, wastewater contained higher turbidity, total solids, HCO3 , and Ca. Population of total coliforms (2.72x104 to 5.2x107) and E. coli. (1.8x103 to 2.64x106) were detected in wastewater. The hydraulic performance of drip emitters was studied for two years (2009 and 2010) with municipal wastewater and ground water using gravel media (F1), disk filter (F2) and combination of gravel and disk filters (F3). Filtration using F3 gave emitter discharge exponent close to 0.5 with R2 value of 0.99. Emitter flow rate decreased with increase in time of operation of the system. Coefficient of variation less than 4% with wastewater and ground water showed excellent performance in surface placed drip lateral after two years of operation. After filtration with F3, coefficient of variation (CVq) of 4.0 % with wastewater and 6.46 % with ground water was observed under subsurface (15 cm deep) placement of laterals.

Evaluation of Hydraulic Performance of Drip Irrigation System

The study was conducted to evaluate the hydraulic performance of drip irrigation system with four emission devices viz dripper, micro-tube, drip-in and drip tape. The different hydraulic measures viz uniformity coefficient. emission uniformity, coefficient of variation and coefficient of manufacturing variation at different spacing and at different operating pressure head were determined by measuring discharge of different emission devices. At a particular spacing, the uniformity coefficient and emission uniformity increased while coefficient of variation decreased as the operating pressure head increased for all emission devices. The coefficient of manufacturing variation was lowest for micro-tubes and highest for drip tape. The suitability/unsuitability of different emission devices was discussed. The micro-tube was not suitable for close spacing. A computer software for hydraulic performance evaluation of drip irrigation system was also developed.

Water requirement of drip irrigated tomatoes grown in greenhouse in tropical environment

Four different levels of drip fertigated irrigation equivalent to 100, 75, 50 and 25% of crop evapotranspiration (ET c ), based on Penman–Monteith (PM) method, were tested for their effect on crop growth, crop yield, and water productivity. Tomato ( Lycopersicon esculentum , Troy 489 variety) plants were grown in a poly-net greenhouse. Results were compared with the open cultivation system as a control. Two modes of irrigation application namely continuous and intermittent were used. The distribution uniformity, emitter flow rate and pressure head were used to evaluate the performance of drip irrigation system with emitters of 2, 4, 6, and 8 l/h discharge. The results revealed that the optimum water requirement for the Troy 489 variety of tomato is around 75% of the ET c . Based on this, the actual irrigation water for tomato crop in tropical greenhouse could be recommended between 4.1 and 5.6 mm day −1 or equivalent to 0.3–0.4 l plant −1 day −1 . Statistically, the effect of depth of water application on the crop growth, yield and irrigation water productivity was significant, while the irrigation mode did not show any effect on the crop performance. Drip irrigation at 75% of ET c provided the maximum crop yields and irrigation water productivity. Based on the observed climatic data inside the greenhouse, the calculated ET c matched the 75–80% of the ET c computed with the climatic parameters observed in the open environment. The distribution uniformity dropped from 93.4 to 90.6%. The emitter flow rate was also dropped by about 5–10% over the experimental period. This is due to clogging caused by minerals of fertilizer and algae in the emitters. It was recommended that the cleaning of irrigation equipments (pipe and emitter) should be done at least once during the entire cultivation period.

Emitter and filter tests for wastewater reuse by drip irrigation

Agriculture is the main user of water in Italy, as in most regions of the world. Particularly in Mediterranean regions, where it is more difficult to meet the agricultural water demand with conventional resources, wastewater reuse represents a viable option. Drip irrigation is particularly suitable for wastewater reuse because it minimises the health risks to farmers and product consumers due to contact with the wastewater. The performance of drip irrigation systems using wastewater is mainly limited by emitter clogging, and this discourages farmers from introducing it. The paper gives the results of experimental trials on the behaviour of six kinds of filters (gravel media, disk and screen) and four types of drip emitters (vortex and labyrinth) using five kinds of municipal wastewater that have not undergone previous advanced treatment. The performance of the emitters and filters tested depends on the quality of the wastewater: total suspended solids and organic matter content influence the percentage of totally clogged emitters, the mean discharge emitted, the emission uniformity coefficient, and the operating time of the filter between cleaning operations. Vortex emitters were more sensitive to clogging than labyrinth emitters. The gravel media filter guaranteed the best performance, but the disk filter, which is cheaper and simpler to manage, assured performance similar to that of the gavel media filter. The test showed the importance of the technology used in manufacturing disk filters. Screen filters were shown to be unsuitable for use with wastewater, with the exception of diluted and settled wastewater. The theoretical discharge of filters, suggested by the manufacturers for clean water, is not adequate for wastewater of the kind used in the trials (suspended solids greater than 78 mg/l and BOD 5 more than 25 mg/l of O 2). The operating times of the filters between cleaning operations, less than 1 h in most trials, suggest the use of automatic cleaning systems. The existing clogging risk classifications proposed for clean water can only be considered reliable for wastewater when labyrinth emitters and gravel or good quality disk filters (such as Arkal) are used; they are not adequate for vortex emitters or screen filters.

Evaluation of Drip Irrigation System in Maharashtra

Experience of the countries which use drip irrigation extensively indicates that the method of drip irrigation enhances the yield of crop, reduces the consumption of water as well as the cost of cultivation. Results of the different research stations in India have also confirmed the importance of drip irrigation in increasing the productivity of the crops and reducing the consumption of water. In India, this method of irrigation was introduced in the early eighties through Government's schemes. Measures have been introduced in the recent years to promote this water saving technology on a large scale. In the Eighth Plan period a centrally sponsored scheme namely "Use of Plastics in Agriculture" has been launched for promotion of various plasticulture techniques like drip irrigatior, mulching and green houses with the objectives of achieving higher productivity with optimum utilisation of water resources. Maharashtra is one of the leading States in using drip irrigation. Large number of farmers have taken benefit of the State and Central schemes of drip irrigation. Present study is undertaken to evaluate the performance of drip irrigation system provided undcr the Government's schemes in Maharashtra.