Ketema Tilahun Zeleke

• PhD
• Lecturer at Charles Sturt University

Rising air temperature and change in rainfall patterns are expected to have impact on agricultural production. The impact of climate change on wheat production was investigated and agronomic adaptation strategies were evaluated for two emission scenarios of Representative Concentration Pathway (RCP4.5 and RCP8.5) and three projection periods (2030,...

A field experiment involving two spring wheat varieties (EGA Gregory and Livingston) was conducted for 2 years (2013 and 2014), late sown in the first year and early sown in the second year, under two soil water regimes (rainfed and supplemental irrigation) at Wagga Wagga, Australia. The FAO’s AquaCrop model version 4.0 was calibrated and validated...

Collecting accurate real-time soil moisture data in crop root zones is the foundation of automated precision irrigation systems. Soil moisture sensors (SMSs) have been used to monitor soil water content (SWC) in crop fields for a long time; however, there is no generally accepted guideline for determining optimal number and placement of soil moistu...

Drip irrigation is widely used in viticulture and other field crops. However, there has been little evidence to date regarding the net effects of diurnal factors on drip irrigation and whether or not irrigating early morning compared to in the afternoon changes the water use efficiency. A field experiment was undertaken to investigate the diurnal f...

Mitigation of the deleterious impacts of climate change on agriculture is a crucial strategy for securing food resources to meet the future demand of the world with a steadily increasing population. We used a pre-validated Agricultural Production Systems sIMulator (APSIM) to explore the implementation of crop residue incorporation (RI) to mitigate...

Core Ideas Canola yield data were analyzed for 144 cultivars over 7 yr and 100 sites. Cultivars showed large differences for the stress tolerance index. Cultivars worthy of further stress‐tolerance studies were identified. G×E crossover analysis showed that adaptation was more often specific than general. Canola ( Brassica napus L.) is a major tem...

Yield of a dryland crop such as wheat is affected by environmental, management and genotypic factors. Field experiments and computer simulations were conducted to understand the effect of supplemental irrigation, type of cultivar and time of sowing (using simulation) on grain yield and quality of two wheat varieties EGA Gregory and Livingston. Ther...

In the arid and semi-arid environments where the rainfall is limited and variable, fallow period soil moisture conservation using stubble is one of the ways of increasing the soil moisture required for crop sowing and development. However, the effectiveness of moisture conservation using stubble depends on the paddock management, soil water content...

Climate variability, cultivar, and sowing date are some of the factors affecting the yield and productivity of a given crop. Evaluating the effect of all these factors, and their combination, through field experimentation is not always feasible. However, validated crop models are efficient and economically effective tools to analyze the influence t...

In arid and semiarid winter crop growing regions of southern Australia, low rainfall, high evaporation, and low soil moisture storage are the limiting factors for crop production. In this region canola (Brassica napus L.) is principally grown in rotation with wheat and pasture species. Some field studies have indicated Indian mustard (Brassica junc...

A field experiment was conducted over 2 years in a semiarid region of Australia to determine the root water uptake–soil water regime relationship and water use of drip-irrigated olive (Olea europaea L.) (cv. Corregiolo). A soil water balance approach was used to estimate the olive trees' water use. Olive evapotranspiration during the first (‘on’) y...

Hydrological models play vital roles in understanding and management of surface water resources. The physically based distributed model Soil and Water Assessment Tool (SWAT) was applied to a small catchment in south eastern Australia to determine its ability to mimic low and high streamflows. The model was successfully calibrated using 1993–2002 st...

Groundwater is fast becoming an alternative source of fresh water for many rural communities in southern Laos in response to increasing rainfall variability and distribution, in conjunction with increasing competition for surface water resources, including for agriculture, hydropower and mining. However, characterisation of the region’s aquifer sys...

Groundwater is fast becoming an alternative source of fresh water for many rural communities in southern Laos in response to increasing rainfall variability and distribution, in conjunction with increasing competition for surface water resources, including for agriculture, hydropower and mining. However, characterisation of the region’s aquifer sys...

Probable impacts of climate change on water resources are a great concern for hydrologists, water managers and policy makers. Global warming and climate change is expected to change the water availability. Using physically based hydrological model Soil and Water Assessment Tool (SWAT), this study assessed the sensitivity of streamflow to individual...

Olive (Olea europaea L.) fruit growth and oil quality is affected by cultivar, degree of maturation and environmental factors such as water availability. In this study, a field experiment was conducted on 12 year old olive trees cv. Corregiola at Wagga Wagga, NSW (Australia) to determine the effect of irrigation and harvest time on olive fruit grow...

This study predicts the probable impacts of climate change on the streamflow of Kyeamba Creek catchment of south eastern Australia. Three climate scenarios (B1, A1B and A2) and the average of four general circulation models (CNRM-CM3, CSIRO-MK3.5, ECHam5 and MIROC3.2) were used to simulate the streamflow for three future periods (2030, 2050 and 209...

A field experiment was conducted on nine olive varieties with the objective of determining the effect of regulated deficit irrigation on olive oil content and physical quality parameters of fruits. Three irrigation levels were applied as a percentage of crop evapotranspiration (ETc) during the pit-hardening period: rainfed, R (0% ETc); deficit, D (...

Water being a major limiting factor in crop production, prediction of the growth and yield response of crop to water is important. Field experiments were conducted in 2009 and 2010 at Wagga Wagga (Australia) to calibrate and validate a water productivity model AquaCrop for canola (Brassica napus L.). The calibrated model was able to accurately simu...

The competition for limited amount of world fresh water is increasing at a fast rate. The agricultural sector is the major water user and also the most inefficient. As a result, the economic return from a unit of water is the lowest for agricultural sector. Therefore, in the wake of dwindling water availability, it is becoming imperative to look fo...

Scarcity of water is the most severe constraint for development of agriculture in arid and semi-arid areas. Under these conditions, the need to use the available water economically and efficiently is unquestionable. Based on the actual crop need, the irrigation management has to be improved so that the water supply to the crop can be reduced while...

Sustainable groundwater management requires knowledge of recharge. Recharge is also an important parameter in groundwater flow and transport models. Spatial variation in recharge due to distributed land-us.e, soil texture, topography, groundwater level, and hydrometeorological conditions should be accounted for in recharge estimation. However, conv...

Improved water management through precise crop water requirement determination is needed to improve the efficiency of water use in agricultural production. As a result, appropriate irrigation scheduling which can lead to water saving, improvements in the yield and income can be designed. In this study, three non-weighing lysimeters having dimension...

Assessment of groundwater vulnerability to pollution is an effective tool for the delineation of groundwater protection zones. DRASTIC approach was used to determine vulnerability zones in Dire Dawa groundwater basin, a semiarid region of Ethiopia. Maps of the seven DRASTIC parameters were prepared. GIS-ArcView was used for mapping and performing w...

The study was conducted to evaluate surge irrigation against continuous irrigation in terms of irrigation and water use efficiencies to produce onion. It was carried out at Mekelle Agricultural Research Center, Ethiopia on 70 m long and 0.6 m center–center spacing furrows of 0.26% average slope on a clay soil. The treatments consisted of factorial...

The study was conducted to evaluate surge irrigation against continuous irrigation in terms of irrigation and water use efficiencies to produce onion. It was carried out at Mekelle Agricultural Research Center, Ethiopia on 70m long and 0.6m center–center spacing furrows of 0.26% average slope on a clay soil. The treatments consisted of factorial co...

In order to plan effective agricultural and water resource projects, it is necessary to understand the spatial and temporal vari-ability of rainfall. Although it is one of the most drought-hit countries in the world, almost no study has ever been conducted in characterising the rainfall pattern of the arid and semi-arid regions of Ethiopia. In this...

A regulated deficit irrigation experiment was conducted at one of the experimental sites of Sekota Agricultural Research Center, Woleh (Ethiopia) on one of the major irrigable crops in the area, onion. The irrigation method was a gravity drip. There were eight treatments with three replications: one period stresses at first, second, third and fourt...

Rainfall and evapo-transpiration are the two major climatic factors affecting agricultural production. While rainfall can be directly measured, evapo-transpiration is estimated from weather data. In this study reference evapo-transpiration ETo was estimated using Penman–Monteith equation, under full data and limited data availability conditions, an...

Field evaluation of surface irrigation systems play a fundamental role to determine the efficiency of the system as it is being used and to identify management practices and system configurations that can be implemented to improve the irrigation efficiency. This study evaluated the performance of an ‘improved’ traditional small-scale irrigation pra...

A study was undertaken to evaluate the performance of sand-traps at Wonji-Shoa Sugar Estate, Ethiopia. Inflow and outflow samples from the sand-traps and deposited sediment samples from the sand-traps, main canal, and reservoirs were taken. The samples were analyzed for sediment concentration and particle size distribution. During the study period,...

The worst-case scenario of NO3-N leaching is often determined using conservative tracers since it undergoes complex and interdependent transformations in the soil. However, few tracer studies have hitherto been done under cropped soil conditions. In this study, a field experiment was conducted to compare Br- transport under bare and maize planted s...

A field-scale tracer study was carried out in a sandy loam Bainsvlei soil of South Africa. The objectives were to study the leaching of solutes in this soil and analyse the result using deterministic and stochastic solute transport models. A rainfall simulator was used to apply water and solution on an area 100 by 100 cm at a flux rate of 5.41 mm/h...

Despite the fact that non-uniform soil water content and variable input water fluxes are usually encountered in the field, tracer experiments have usually been carried out under steady-state conditions. The objective of this study was to analyse solute transport in a Bainsvlei soil under intermittent water application using Br– as a tracer. Sprinkl...

Bromide is commonly used to simulate the movement of nitrate fertilisers through the soil profile. However, there exists no comparative evaluation of the leaching properties of Br -and NO 3 --N under local soil and rainfall conditions at Bloemfontein. The purpose of this work was to conduct a field experiment to evaluate the leaching behaviour of B...

The problem of designing farm irrigation systems is complicated by the fact that the return from a project is a function not only of the design variables, but also of the operation schedules. These operation decisions are not independent, as irrigation applications at any given time period affect the entire set of applications to be made in the fut...