Engenharia de Sistemas de Irrigação e Drenagem

Over 80 percent of Kenya’s freshwater withdrawals are utilized in agricultural production. The increase in human population means that even more water will be channeled towards food production. Improving water productivity is the most appropriate strategy for increasing food production for a fast growing population due to its consideration of the sustainability of water resources. Kenya predominantly depends on rain-fed agriculture for its food production, and this exposes the country to acute food shortages during droughts. Beans (Phaseolus vulgaris L.) are the primary source of protein for most households in Kenya. Despite this fact, there is a supply deficit during dry spells. An irrigation project was carried out at Moi University with an objective to study the effect of deficit irrigation as a mitigation measure to curb the shortage of beans during dry spells while ensuring sustainable use of water resources. This was carried out through modelling of water productivity (WP) and yield (Y) of beans using the FAO AquaCrop model. Field experiments were set up in a Randomized Complete Block Design (RCBD) arranged in split plots and replicated three times. Two water treatment strategies were employed (deficit irrigation, full irrigation). In the full irrigation supply, the crop was kept at 100% of irrigation requirement (T100) and data collected from these plots was used in Aqua Crop model calibration. There were three levels of deficit irrigation used: 80%, 60%, and 50% of irrigation requirement (T80, T60, T50), these were used in model validation. The highest WP, as well as the lowest yield reduction of 2.4%, was observed in the T80 treatment, this signifies water savings of up to 20%, which translates to 750 m³/ha. The highest yield reduction of 59.8% was obtained in T50 treatment, coupled with a drop in WP. Deficit irrigation results in yield reduction as observed in this study, but the amount of water saved can be used to irrigate more land or be utilized elsewhere. Consequently, it is necessary for Kenya to adopt deficit irrigation to ensure food security during dry spells while at the same time ensure sustainable water use.

This study was aimed to compare estimation methods of crop water requirement and irrigation scheduling for major crops using different models and compare the significance of models for adoption at different situations in Metekel zone. Crop water requirement and irrigation scheduling of maize in selected districts of Metekel zone were estimated using CropWat model based on soil, crop and meteorological data and AquaCrop based on soil, crop and meteorological data including Co2, groundwater, field management, and fertility status. Model performance was evaluated using Normalized Root mean square errors (NRMSE), model by Nash-Sutcliffe efficiency (NSE), Prediction error (Pe), and Model efficiency (MF). It is observed that the maximum reference evapotranspiration in the study area was found to be 7.1 mm/day in Guba and minimum reference evapotranspiration was 2.9 mm/day in Bullen district. In all cases, the maximum ETo in all districts was fund to in March and the lowest in August. The maximum ETc of maize was found to be 702.4 mm in Guba district and minimum ETc was found to be 572.6 mm in Bullen district using CropWat but the effective rainfall (Pe) for maize were determined as 185 mm respectively in Wembera district. However, using AquaCrop model the maximum ETc of 565 mm was recorded in Guba but 425 mm was recorded as minimum in Wembera district for irrigated maize in the study area. The study revealed that the irrigation scheduling with a fixed interval criterion for maize 10 days with 12 irrigation events has been determined. Moreover, furrow irrigation with 60% irrigation application efficiency was adjusted during irrigation water applications for all districts. The performance of the irrigation schedule and crop response was evaluated by the analysis results in the simulation using different models. It has been observed that there was a strong relationship and a significant relation between the simulated and observed values for validation. Hence, Normalized Root mean square errors (NRMSE), model by Nash-Sutcliffe efficiency (NSE), Prediction error (Pe), and Model efficiency (MF) showed that AquaCrop model well simulated in all parameters considered. AquaCrop model is the most suitable soil-water-crop-environment management model, so future studies should suggest a focus on addressing deficit irrigation strategy with different field management conditions to improve agricultural water productivity under irrigated agriculture for the study area for major crops.

Internet of things (IoT) also called internet of everything (IoE) are network of physical object having connectivity with the internet. IoT is broad field with several new and advanced trends which made more suitable to implement and connect over the remote areas. IoT became more suitable platform in several applications with the emergence of the other field. IoT provide fast solution of the several real life problems with integration of the new trends and techniques. The field of automation is need of this era with other smart and advanced features bought up with new way of the handling the problems. IoT is the concept which can be applied globally over the networks of the things for solving the problem of the manual control especially in remote applications. This study reviews important aspects of water irrigation in IoT. However, it covers the challenges, applications and water pollution.

Sugarcane is one of the most important commercial crops cultivated mostly on the large scale basis all over the world from arid to semi-arid climate condition like Ethiopia. Wonji shoa sugarcane plantation was the first large scale irrigation in Ethiopia. But sugarcane crop is the most water intensive crop that requires critical determination of its evapotranspiration. Determination of crop evapotranspiration is more accurate through experiment but experiment was not mostly undertaken due to high cost, lack of instruments and laboratory facilities, and time it required. But to overcome those problems, some models were developed as an option in determining the crop evapotranspiration. In line with this, the current study focused on the performance evaluation of sugarcane evapotranspiration determined by different models as compared to the lysimeter experiment under study area. The main objective of this study was to analysis the variation of sugarcane evapotranspiration measured from the lysimeter experiment and that determined using different models under the current study climatic condition. In the current study, Blaney-Criddle, Drooger and Allen, Hargreaves, Irmak, Tabari and Thornthwaite were selected. The selected models were required only few climatic parameters. After reference evapotranspiration was determined by each selected models, the sugarcane evapotranspiration was determined by multiplying those reference evapotranspiration by crop coefficient recommended by FAO-56. The performances of those models were evaluated using the most commonly used statistical indices. Those statistical indices used were RMSE, MBE, t-test, R² and IA. After all the data computed by each selected models the analysed, Blaney-Criddle model was the best model in determining the sugarcane evapotranspiration as compared to the lysimeter experiment followed by Irmak models. Therefore, from the current findings, it can be concluded that Blaney- Criddle model can be used to determine sugarcane evapotranspiration under current study climatic condition.

The middle 19^th century irrigation development historyof the world,especially Green Revolution, taught us that intensive irrigation expansion has the power and is also the key to eradicate food shortages of some nations. At the same period, an attempt was made to improve irrigation sector of Ethiopia but not successful as Asian countries.The paper tried to present the pathways Ethiopian irrigated agriculture so far travelled based on comprehensive reviews substantiated by indepth analyses. From the irrigation policies and development plans up to organizational setups, diverse but critical platforms which troubled its development evolutions have been raised and criticised. Effects of these platforms or their aftermaths on targeted development plans; on data of irrigated areas and potentials as well as on performances of irrigation schemes have also been analytically quantified and thoroughly discussed. In general, development of the sector is still stumbling for half a century and unable to contribute for food selfsufficiency and economic growth. The country donot have clear irrigation policy; the sector is supported with low financial backups; organizational structure is shacky and misaligned; the institution are weak so that irrigated areas and potentials are unknown or the figures are inconsistent; scheme categorization is confusing; improperly planned developments are failed and stagnated; large scheme development are stagnated and too slow to change the economy. For the last 60 years less than 0.65 million ha is developed in the country. Irrigation efficiencies of the schemes is below 35%. Finally, overhauling the sector as a whole is recommended if real development is expected.