灌溉排水系统工程

Appling appropriate field irrigation practices safeguard that crops could get peak supply of water in their root zone for achieving best yield of crops without facing water stress and damaging the quality of soils. Sugar cane fields at study area irrigated to irrespective of the soil type, growing month, and stage of crop growth with the design application efficiency of 70%. Currently the system was not working with the full design capacity so that evaluating the irrigation scheduling under existing condition was very important. Therefore, this study was conducted to evaluate irrigation scheduling with design standards, and develop irrigation scheduling based on the actual existing water application with respect of soil, growing month and stage of growth. Representative soil samples were taken for soil texture, bulk density, field capacity and wilt point test. Secondary data collected were weather data, effective root depth and crop coefficient. The performance parameters analyzed were, crop evapotranspiration, net irrigation requirement, net depth of application, irrigation interval, sprinkler set hour, and application efficiency. The average sprinkler discharge at 3.0 and 2.5 bar operating pressure was 0.9 and 0.8 m3/h respectively. The sprinklers had an average actual application efficiency of 62%. Sprinkler set hours obtained for the age of 0-3, 3-6, 6-15 and >15 month was 13, 19, 25 and 38 h respectively. Irrigation interval obtained for age of 0-3, 3-6, 6-15 and >15 month varied with growing month and had a range of 7-10, 6-21, 7-20, and 16-24 days respectively. According to the study the system was not working under full design capacity. The irrigation scheduling based on the system actual working condition was recommended with respect of growing month and stage of growth.

Northern Buenos Aires (Argentina) is a rain fed agricultural region. Complementary irrigation, which is mainly used in maize crop, requires the contemplation of strategies that minimize the soil solidification risk. The first alternative to mitigate the limited water quality is to perform an irrigation schedule by using the water balance methodology. The BAHICU software, developed in the study region, is a soil water balance model for agricultural systems under irrigation. The objective of the present study was to evaluate the forage production of irrigated and rain fed double crop of silage maize, using the BAHICU software as a tool to make a more efficient water use and to attenuate the adverse effect of the sodium present in the irrigation water. A field experiment was conducted on a clay soil with a sequence of two maizes during the 2015-2016 growing season: short season maize (maize 1) and late sown maize (maize 2). There were two preceding winter crops: ryegrass and oat. Plant height, dry matter (DM) percentage and DM yield were measured. Crop evapotranspiration (ETc) of irrigated and rain fed treatments was obtained from the BAHICU software. Irrigation was applied using a sprinkler system. Irrigation influenced only the yield of maize 2. Water use efficiency (WUE) did not vary with irrigation incorporation. Maize 2 presented higher forage production and WUE than maize 1. An R2 value of 0.82 was found after relating DM yield with maize ETc. The preceding winter crops only influenced the yield of the maize 1. The DM yield was linked to plant height. The irrigated maize 2 was the only treatment that presented an optimal DM percentage for silage conservation. Using the BAHICU software allowed comparing the WUE of the maizes analyzed. Irrigation influenced crop yield but not WUE.

The study was conducted at Wondo Genet Agricultural Research Center, Koka research station, Ethiopia, 8°26’ N latitude, 39°02’ E longitude and 1602 m.a.s.l. based on the objective to select most effective water saving techniques and improve water productivity of irrigated maize (Zea mays L.). Three types of furrow irrigation methods (alternate, fixed and conventional furrow irrigation methods) and two mulch types and no mulch with three replications were used as two factors to evaluate the yield and yield component including water use efficiency of maize in split-plot design. Different types of irrigation method highly significantly (p<0.01) affected all the studied parameters of yield and yield components of maize at Koka both season except number of grains per cob. Moreover, maize growth, yield and yield components were highly significantly (p<0.01) influenced due to different mulch types used. However, there was no interaction effect due to the two factors studied (irrigation type and mulching type). Significantly a higher growth, yield and yield component of maize was recorded due to conventional furrow irrigation method than alternate and fixed furrow irrigation method. However, higher water use efficiency was obtained due to alternate furrow irrigation method. Moreover, higher growth, yield and yield components including water use efficiency were obtained due to plastic mulch than no mulch and straw mulch for maize at koka. Therefore, for maximizing grain yield under no water stress scenario, irrigation of maize with conventional furrow irrigation methods could be used. On the other hand, under limiting irrigation water resource condition, irrigation of maize could be done with alternate furrow irrigation method with plastic mulch application to minimize evaporation loss and maximize water productivity of maize at Koka and similar agro-ecology and soil type.

The country Ethiopia is situated in East Africa and hence agriculture is the base for people’s basic fulfillment and the country is abundant by water resource. Even if we have ample amount of water still now rain-fed agriculture is more practiced than irrigation water application. Irrigation can be defined as the application of water to the soil for increasing the moisture content which is important for plant root-growth and development to prevent stress that may cause reduce the amount of yield as well as the quality of the crops. There is positive relation between irrigation service and poverty alleviation. The availability of water for irrigation in community helps to improve food security. It increases the potential for producing more food consistency in drought prone and food insecure areas. Small scale irrigation farming has played a vital role in enabling food production by lowering the risk of crop failure and sustaining households and food security status. Extension works should be done to aware the importance of irrigation system and the involvement of the local farmers could be include when the system is going to be efficient. Government and other related policy formulation organizations should focused on decentralized system among the users. Irrigation is more effective if all users and non-users participate actually during the planning, implementing, maintaining, monitoring and evaluating works. The participation of the stakeholders is pillar during the management and sustainability of the irrigation structures

Crop evapotranspiration estimation is critical for sustainable water management under the semiarid and arid climate in New Mexico. While irrigation scheduling is based on daily evapotranspiration through the two step approach, reference evapotranspiration and crop coefficients should be determined with accuracy. The utilization of grass reference evapotranspiration (ETo) or alfalfa reference evapotranspiration (ETr) and the conversion from one to the other calls for an understanding of the relationship between ETr and ETo. The objectives of this study were to develop the ratio of ETr to ETo values (Kr) and to determine the variability of Kr during the year for six locations across the State of New Mexico (USA). The results showed long term annual Kr values to vary from 1.28 to 1.45 and the coefficient of determination varied from 0.96 to 0.98. Kr value decreases from January to July and increases from August to December and was at its lowest Kr value at the peak daily reference evapotranspiration. Annual average Kr values were 1.31, 1.38, 1.43, 1.38, 1.38 and 1.48 at Alcalde, Fabian Garcia, Farmington, Leyendecker, Las Cruces and Tucumcari locations and the growing season average Kr values were 1.24, 1.32, 1.38, 1.31, 1.32 and 1.42 at the respective locations. The strong correlation between ETr and ETo allows the conversion of the grass reference evapotranspiration to alfalfa reference evapotranspiration and vice versa however, caution should be taken when using the crop coefficient values to convert either ETo or ETr to actual crop evapotranspiration for irrigation scheduling and water management.

The objective of this study was, to evaluate the effects of deficit irrigation on yield and water productivity (WP) of onion crop grown under Ambo condition. Field experiment was conducted at Ambo Agricultural Research Center in Ethiopia. The treatments consisted of nine different treatments replicated three times arranged in RCBD. The experiment involved two categories of deficit with different timings: 1) skipping of irrigation during one particular phenological stage and application of 75% ETc during the rest of the growing stages and 2) no watering during specific phenological stage and watering with 50% ETc during the remaining stages. Amount of water applied was monitored using standard Parshall flume. The highest total onion yield (46.7t/ha) was obtained from full irrigated treatment, which was not statically different from treatments that were not irrigated during initial growth stage and irrigated with 75% ETc during the rest of phenological stages (T2) and treatment with no irrigation during bulb maturity stage and irrigated with 75% ETc otherwise (T5) (P<0.05). The second category of treatment (irrigation with 50% ETc) resulted high water saving and yield reduction which may not be attractive for producers. WP varied from 7.7 kg/m3 for control and 14.9 kg/m3 for the 50% stressed and not irrigated during maturity stage. T2 and T5 produced WP values of 10.8 and 13.1 kg/m3 respectively. From resources conservation point of view, maximum water productivity may be of interest, which could be obtained under sever deficit irrigation. However, such consequences on yield may not be tolerable from producers view point. The recommended depth of irrigation would be 75% ETc during development, bulb formation, maturity stages and skipping during initial growth stage. Skipping irrigation during maturity stages and irrigating with 75% ETc otherwise has more water saving and WP enhancement potential with tolerable level of yield reduction.

Under changing climate and the global warming, accurate estimation of crop evapotranspiration might help improving water management and maintaining or improving water productivity. The objective of this study was to compare the sum of hourly ETo with the daily average ETo using the standardized ASCE Penman-Monteith equation under semiarid dry climate. Pair comparison was performed between the sum of hourly reference evapotranspiration (ETo) and the daily average ETo based on the data from four automated weather stations in the State of New Mexico (USA) for the period of 2009-2017. The results showed good agreement between the sum of hourly ETo and daily average ETo with the regression slopes varying from 1.00 to 1.10 and coefficients of determination from 0.63 to 0.97. The least difference between the hourly and daily results was found at Leyendecker. The RMSE values were 0.98, 0.64, 0.21 and 0.35 mm/day at Fabian Garcia, Farmington, Leyendecker and Tucumcari, respectively. The adoption of the hourly ETo estimation method leads to 16.6, 5.5, -0.2, and 4.1% higher annual ETo at Fabian Garcia, Farmington, Leyendecker and Tucumcari respectively, and can help on accurate evapotranspiration estimation to meet crop water requirement under sustainable agriculture.

Six Maize genotypes were planted in RCBD with three replication each in 10 m by 10 m plot by furrow irrigation to evaluate adaptation performance of Maize genotypes and identify high yielding and heat tolerant genotypes adapted to Tendaho sugar estate in order to enhance the net national crop production in general and product diversification in sugar estates in particular in the near future. The analysis of variance showed that genotypes included in the test differed highly and significantly at (p=0.05) probability level for all traits and maize grain yield mean value comparison or mean separation result indicated that the genotype BH-546 is superior compared to others with 58.5 quintals grain yield per hectare followed by MH-4 and BH-540 genotypes with 50.3 and 43 quintals grain yield per hectare value. Based on the productivity standard the superior genotype BH-546 scored 95% and 17%, respectively yield advantage over the national (30 qt/ha) and global (50 qt/ha) maize average productivity.