Managing water resources in Libya through reducing irrigation water demand: more crop production with less water use

2013 ◽  
Vol 44 ◽  
pp. 95-102
Author(s):  
Saad Ahmad Alghariani

AbstractThe looming water crisis in Libya necessitates taking immediate action to reduce the agricultural water demand that consumes more than 80% of the water supplies. The available information on water use efficiency and crop water productivity reveals that this proportion can be effectively reduced while maintaining the same, if not more, total agricultural production at the national level. Crop water productivity, which is depressingly low, can be doubled through implementing several measures including relocating all major agricultural crops among different hydroclimatic zones and growth seasons; crop selection based on comparative production advantages; realisation of the maximum genetically determined crop yields; and several other measures of demand water management. There is an urgent need to establish the necessary institutional arrangements that can effectively formulate and implement these measures as guided by agricultural research and extension services incorporating all beneficiaries and stakeholders in the process.

2007 ◽  
Vol 363 (1491) ◽  
pp. 639-658 ◽  
Author(s):  
J.I.L Morison ◽  
N.R Baker ◽  
P.M Mullineaux ◽  
W.J Davies

Globally, agriculture accounts for 80–90% of all freshwater used by humans, and most of that is in crop production. In many areas, this water use is unsustainable; water supplies are also under pressure from other users and are being affected by climate change. Much effort is being made to reduce water use by crops and produce ‘more crop per drop’. This paper examines water use by crops, taking particularly a physiological viewpoint, examining the underlying relationships between carbon uptake, growth and water loss. Key examples of recent progress in both assessing and improving crop water productivity are described. It is clear that improvements in both agronomic and physiological understanding have led to recent increases in water productivity in some crops. We believe that there is substantial potential for further improvements owing to the progress in understanding the physiological responses of plants to water supply, and there is considerable promise within the latest molecular genetic approaches, if linked to the appropriate environmental physiology. We conclude that the interactions between plant and environment require a team approach looking across the disciplines from genes to plants to crops in their particular environments to deliver improved water productivity and contribute to sustainability.


2020 ◽  
Author(s):  
Iman Haqiqi ◽  
Danielle S. Grogan ◽  
Thomas W. Hertel ◽  
Wolfram Schlenker

Abstract. Agricultural production and food prices are affected by hydroclimatic extremes. There has been a large literature measuring the impacts of individual extreme events (heat stress or water stress) on agricultural and human systems. Yet, we lack a comprehensive understanding of the significance and the magnitude of the impacts of compound extremes. Here, we combine a high-resolution weather product with fine-scale outputs of a hydrological model to construct functional indicators of compound hydroclimatic extremes for agriculture. Then, we measure the impacts of individual and compound extremes on crop yields focusing on the United States during the 1981–2015 period. Supported by statistical evidence, we confirm that wet heat is more damaging than dry heat for crops. We show that the average damage from heat stress has been up to four times more severe when combined with water stress; and the value of water experiences a four-fold increase on hot days. In a robust framework with only a few parameters of compound extremes, this paper also improves our understanding of the conditional marginal value (or damage) of water in crop production. This value is critically important for irrigation water demand and farmer decision-making – particularly in the context of supplemental irrigation and sub-surface drainage.


2019 ◽  
Vol 62 (5) ◽  
pp. 1377-1393
Author(s):  
Steven R. Evett ◽  
Gary W. Marek ◽  
Paul D. Colaizzi ◽  
David K. Brauer ◽  
Susan A. O’Shaughnessy

Abstract. Greater than 80% of the irrigated area in the Southern High Plains is served by center-pivot irrigation, but the area served by subsurface drip irrigation (SDI) is increasing due to several factors including declining well yields and improved yields and crop water productivity (CWP), particularly for cotton. Not as well established is the degree to which the reduced soil water evaporation (E) in SDI systems affects the soil water balance, water available to the crop, and overall water savings. Grain corn ( L.) and sorghum ( L. Moench) were grown on four large weighing lysimeters at Bushland, Texas, in 2013 (corn), 2014 and 2015 (sorghum), and 2016 (corn). Evapotranspiration (ET) was measured using the lysimeters and using a neutron probe in the surrounding fields. Two of the lysimeters and surrounding fields were irrigated with SDI, and the other two were irrigated with mid-elevation spray application (MESA). The lysimeter-measured evaporative losses were 149 to 151 mm greater from sprinkler-irrigated corn fields than from SDI fields. When growing sorghum, the lysimeter-measured evaporative losses were 44 to 71 mm greater from sprinkler-irrigated fields than from SDI fields. The differences were affected by plant height and became smaller when plant height reached the height of the spray nozzles, indicating that the use of LEPA or LESA nozzles could decrease the evaporative losses from sprinkler-irrigated fields in this region with its high evaporative demand. Annual weather patterns also influenced the differences in evaporative loss, with increased differences in dry years. SDI reduced overall corn water use by 13% to 15%, as determined by neutron probe, while either not significantly affecting yield (2016) or increasing yield by up to 19% (2013) and increasing CWP by 37% (2013) to 13% (2016) as compared with MESA full irrigation. However, sorghum yield decreased by 15% and CWP decreased by 14% in 2014 when using SDI compared with MESA full irrigation due to an overly wet soil profile in the SDI fields and deep percolation that likely caused nutrient losses. In 2015, there were no significant sorghum yield differences between irrigation methods. Sorghum CWP was significantly greater (by 14%) in one SDI field in 2015 compared with MESA fully irrigated sorghum. Overall, sorghum CWP increased by 8% for SDI compared with MESA full irrigation in 2015. These results indicate that SDI will be successful for corn production in the Texas High Plains, but SDI is unlikely to benefit sorghum production. Keywords: Corn, Crop water productivity, Evaporative loss, Evapotranspiration, Irrigation application method, Sorghum, Water use efficiency, Weighing lysimeter.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Sisay Ambachew Mekonnen ◽  
Assefa Sintayehu

Sesame (Sesamum indicum L.) is the leading oil seed crop produced in Ethiopia. It is the second most important agricultural commodity for export market in the country. It is well suited as an alternative crop production system, and it has low crop water requirement with moderate resistance to soil moisture deficit. The low land of North Western Ethiopia is the major sesame producer in the country, and the entire production is from rainfed. The rainfall distribution in North Western Ethiopia is significantly varied. This significant rainfall variability hampers the productivity of sesame. Irrigation agriculture has the potential to stabilize crop production and mitigate the negative impacts of variable rainfall. This study was proposed to identify critical growth stages during which sesame is most vulnerable to soil moisture deficit and to evaluate the crop water productivity of sesame under deficit irrigation. The performance of sesame to stage-wise and uniform deficit irrigation scheduling technique was tested at Gondar Agricultural Research Center (Metema Station), Northern Western Ethiopia. Eight treatments, four stage-wise deficit, two uniform deficit, one above optimal, and one optimal irrigation applications, were evaluated during the 2017 irrigation season. The experiment was designed as a randomized complete block design with three replications. Plant phenological variables, grain yield and crop water productivity, were used for performance evaluation. The result showed that deficit irrigation can be applied both throughout and at selected growth stages except the midseason stage. Imposing deficit during the midseason gave the lowest yield indicating the severe effect of water deficit during flowering and capsule initiation stages. When deficit irrigation is induced throughout, a 25% uniform deficit irrigation can give the highest crop water productivity with no or little yield reduction as compared with optimal irrigation. Implementing deficit irrigation scheduling technique will be beneficial for sesame production. Imposing 75% deficit at the initial, development, late season growth stages or 25% deficit irrigation throughout whole seasons will improve sesame crop water productivity.


2014 ◽  
Vol 41 (11) ◽  
pp. 1199 ◽  
Author(s):  
Neil C. Turner ◽  
Abraham Blum ◽  
Mehmet Cakir ◽  
Pasquale Steduto ◽  
Roberto Tuberosa ◽  
...  

The objective of the InterDrought conferences is to be a platform for debating key issues that are relevant for increasing the yield and yield stability of crops under drought via integrated approaches. InterDrought-IV, held in Perth, Australia, in September 2013, followed previous InterDrought conferences in bringing together researchers in agronomy, soil science, modelling, physiology, biochemistry, molecular biology, genetics and plant breeding. Key themes were (i) maximising water productivity; (ii) maximising dryland crop production; (iii) adaptation to water-limited environments; (iv) plant productivity under drought through effective water capture, improved transpiration efficiency, and growth and yield; and (v) breeding for water-limited environments through variety development, and trait-based genomics-assisted and transgenic approaches. This paper highlights some key issues and presents recommendations for future action. Improved agronomic interventions were recognised as being important contributors to improved dryland crop yields in water-limited environments, and new methods for exploring root architecture and water capture were highlighted. The increase in crop yields under drought through breeding and selection, the development of high-throughput phenotyping facilities for field-grown and pot-grown plants, and advances in understanding the molecular basis of plant responses and resistance to drought stress were recognised. Managed environment phenotyping facilities, a range of field environments, modelling, and genomic molecular tools are being used to select and release drought-resistant cultivars of all major crops. Delegates discussed how individuals and small teams can contribute to progress, and concluded that interdisciplinary research, linkages to international agricultural research centres, public–private partnerships and continuation of the InterDrought conferences will be instrumental for progress.


Author(s):  
K. Avil Kumar ◽  
M. Uma Devi ◽  
M.D. Reddy ◽  
A. Mani ◽  
D.V. Mahalaxmi ◽  
...  

Background: India is facing high water stress and it is amongst those with the most fragile and uncertain water resource countries in the world. Crop productivity depends on quality of input supply including seeds, fertilizers, pesticides and supported by irrigation facilities. In India, ground water irrigates more than 61% of net cropped area and much of water being used for irrigating rice crop. The disproportionate water uses for crop production results in poor water productivity. The planning of water resources could be achieved by knowing the crop water requirements in different seasons and productivity of water. Hence, study was taken up to assess the water use and productivity of crops under intensively ground water irrigated watershed.Methods: A study conducted to assess the water use and productivity of different crops grown in Kothakunta sub watershed (having 206 working bore wells with cultivated area of 203.5 ha) in Siddipet district of Telangana, India during kharif and rabi season of 2008 to 2012, data were collected from 147 farmers on rice, maize, cotton, potato, flora beans and tomato crops grown under irrigation. The water applied to crops was measured by fixing water meters at the end of water delivery pipe and recorded the quantity of water applied each time. For rice crop four plots were taken and for other crops two plots were taken for measuring the water. The water use and productivity were assessed by using standard procedure. Result: The water productivity was found to be higher to vegetables, which ranged between 2.43 kg of potato, 1.57 kg of beans and 1.26 kg of tomato than cereals (0.79 kg for maize and 0.39 kg for rabi rice) per cubic meter of irrigation water consumed. Water productivity in terms of monetary return (₹) per cubic meter of water consumed was higher with beans (₹ 17.20) in contrast to potato (₹ 16.12). Rice equivalent yield (REY) calculated per cubic meter of irrigation water consumption was very similar to economic return (₹ per cubic meter of water).


2020 ◽  
Author(s):  
Sehouevi Mawuton David Agoungbome ◽  
Nick van de Giesen ◽  
Frank Ohene Annor ◽  
Marie-Claire ten Veldhuis

<p>Africa’s population is growing fast and is expected to double by 2050, meaning the food production must follow the cadence in order to meet the demand. However, one of the major challenges of agriculture in Africa is productivity (World Bank, 2009; IFRI, 2016). For instance, more than 40 million hectares of farmland were dedicated to maize in Africa in 2017 (approx. 20% of world total maize farms), but only 7.4% of the total world maize production came from the African continent (FAO, 2017). This shows the poor productivity which has its causes rooted in lack of good climate and weather information, slow technology uptake and financial support for farmers. In West Africa, where more than 70% of crop production is rain-fed, millions of farmers depend on rainfall, yet the region is one of the most vulnerable and least monitored in terms of climate change and rainfall variability. With a high uncertainty of future climate conditions in the region, one must foresee the big challenges ahead: farmers will be exposed to a lot of damages and losses leading to food insecurity resulting in famine and poverty if measures are not put in place to improve productivity. This study aims at addressing low productivity in agriculture by providing farmers with the right moment to start farming in order to improve efficiency and productivity of crop water use. By analyzing yield response to water availability of specific crops using AquaCrop, the Food and Agriculture Organization crop growth model, we investigate the crop water productivity variability throughout the rainy season and come up with recommendations that help optimize rainfall water use and maximize crop yield.</p>


2020 ◽  
Author(s):  
Imeshi Weerasinghe ◽  
Celray James Chawanda ◽  
Ann van Griensven

<p>Evapotranspiration (ET) or the water vapour flux is an important component in the water cycle and is widely studied due to its implications in disciplines ranging from hydrology to agricultural and climate sciences. In the recent past, growing attention has been given to estimating ET fluxes at regional and global scales. However, estimation of ET at large scales has been a difficult task due to direct measurement of ET being possible only at point locations, for example using flux towers. For the African continent, only a limited number of flux tower data are openly available for use, which makes verification of regional and global ET products very difficult. Recent advances in satellite based products provide promising data to fill these observational gaps.</p><p>In this study we propose to investigate the Climate Change (CC) impact on crop water productivity across Africa using ET and crop yield predictions of different crop models for future climate scenarios. Different model outputs are evaluated including models from both the ISI-MIP 2a and 2b protocols. Considering the problem of direct observations of ET being difficult to obtain, especially over Africa, we use ET estimates from several remotely sensed derived products as a references to evaluate the crop models (maize) in terms of magnitude, spatial patterns and variations between models. The crop model results for crop yield are compared to FAO reported crop yields at country scale. The results show a very strong disagreement between the different crop models of the baseline scenario and when compared with ET and crop yield data.  Also, a very large uncertainty is obtained for the climate change predictions. It is hence recommended to improve the crop models for application in Africa.</p>


2020 ◽  
Author(s):  
Muhammad Usman ◽  
Talha Mahmood ◽  
Christopher Conrad

<p>Textile products made with cotton produced in Pakistan, Turkey, and Uzbekistan are largely imported to European markets. This is responsible for high virtual water imports from these countries and thus puts immense pressure on their water resources, which is further extravagated due to climate change and population growth. The solution to combat the issue, on one hand, is to cut water usage for cotton irrigation, and on the other hand, to increase water productivity. The biggest challenge in this regard is the correct quantification of consumptive water use, cotton yield estimation and crop water productivities at a finer spatial resolution on regional levels, which is now possible by utilizing remote sensing (RS) data and approaches. It can also facilitate comparing regions of interest, like in this study, Pakistan, Turkey, and Uzbekistan by utilizing similar data and techniques. For the current study, MODIS data along with various climatic variables were utilized for the estimation of consumptive water use and cotton yield estimation by employing SEBAL and Light Use Efficiency (LUE) models, respectively. These estimations were then used for working out water productivities of different regions of selected countries as case studies. The results show that the study area in Turkey achieved maximum cotton water productivity (i.e. 0.75 - 1.2 kg.m<sup>-3</sup>) followed by those in Uzbekistan (0.05 – 0.85 kg.m<sup>-3</sup>) and Pakistan (0.04 – 0.23 kg.m<sup>-3</sup>).  The variability is higher for Uzbekistan possibly due to agricultural transition post-soviet-union era. In the case of Pakistan, the lower cotton water productivities are mainly attributed to lower crop yields (400 – 1200 kg.ha<sup>-1</sup>) in comparison to Turkey (3850 – 5800 kg.ha<sup>-1</sup>) and Uzbekistan (450 – 2500 kg.ha<sup>-1</sup>). Although the highest crop water productivity is achieved for the study region in Turkey, there is still potential for further improvement by introducing on-farm water management. In the case of the other two countries, especially for Pakistan, major improvements are possible through maximizing crop yields. The next steps include comparisons of the results in economic out-turns.</p>


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