scholarly journals Agro-Economic Water Productivity-Based Hydro-Economic Modeling for Optimal Irrigation and Crop Pattern Planning in the Zarrine River Basin, Iran, in the Wake of Climate Change.

Author(s):  
Farzad Emami ◽  
Manfred Koch

For water-stressed regions like Iran improving the effectiveness and productivity of agricultural water-use is of utmost importance due to climate change and unsustainable demands. Therefore, a hydro-economic model has been developed here for the Zarrine River Basin with the central concept of that demands are value-sensitive functions, where quantities of water-uses at different locations and times have a changeable economic benefits. To do this, the potential crop yields and the surface and groundwater resources, especially Boukan Dam inflow are simulated using the hydrologic model, SWAT, based on predicted climatic scenarios i.e. quantile mapping-downscaled projections. Then, to allocate the agricultural water based on the agro- economic crop water productivity (AEWP) of crops, a basin-wide water management tool, MODSIM, is customized. Next, a simulation- optimization model has been developed using a coupled CSPSO-MODSIM, to optimize the total AEWP, considering climatic impact and crop pattern scenarios, for 2020-2038, 2050-2068 and 2080-2098 periods. Finally, the optimum crop pattern and crop water irrigation depths are presented for different RCPs and periods. The results indicated that this approach will improve considerably the AEWPs and decrease the agricultural water-use up to 40%. Thus, this integrated model is able to support water authorities and other stakeholder in a water-scarce basin, as is the study area.

2018 ◽  
Vol 10 (11) ◽  
pp. 3953 ◽  
Author(s):  
Farzad Emami ◽  
Manfred Koch

For water-stressed regions/countries, like Iran, improving the management of agricultural water-use in the wake of climate change and increasingly unsustainable demands is of utmost importance. One step further is then the maximization of the agricultural economic benefits, by properly adjusting the irrigated crop area pattern to optimally use the limited amount of water available. To that avail, a sequential hydro-economic model has been developed and applied to the agriculturally intensively used Zarrine River Basin (ZRB), Iran. In the first step, the surface and groundwater resources, especially, the inflow to the Boukan Dam, as well as the potential crop yields are simulated using the Soil Water Assessment Tool (SWAT) hydrological model, driven by GCM/QM-downscaled climate predictions for three future 21th-century periods under three climate RCPs. While in all nine combinations consistently higher temperatures are predicted, the precipitation pattern are much more versatile, leading to corresponding changes in the future water yields. Using the basin-wide water management tool MODSIM, the SWAT-simulated water available is then optimally distributed across the different irrigation plots in the ZRB, while adhering to various environmental/demand priority constraints. MODSIM is subsequently coupled with CSPSO to optimize (maximize) the agro-economic water productivity (AEWP) of the various crops and, subsequently, the net economic benefit (NEB), using crop areas as decision variables, while respecting various crop cultivation constraints. Adhering to political food security recommendations for the country, three variants of cereal cultivation area constraints are investigated. The results indicate considerably-augmented AEWPs, resulting in a future increase of the annual NEB of ~16% to 37.4 Million USD for the 65%-cereal acreage variant, while, at the same time, the irrigation water required is reduced by ~38%. This NEB-rise is achieved by augmenting the total future crop area in the ZRB by about 47%—indicating some deficit irrigation—wherefore most of this extension will be cultivated by the high AEWP-yielding crops wheat and barley, at the expense of a tremendous reduction of alfalfa acreage. Though presently making up only small base acreages, depending on the future period/RCP, tomato- and, less so, potato- and sugar beet-cultivation areas will also be increased significantly.


2021 ◽  
Author(s):  
Shikun Sun ◽  
Yihe Tang

<p>The agriculture sector is one of the largest users of water and a significant source of greenhouse gas (GHG) emissions. The development of low-GHG-emission and water-conserving agriculture will inevitably be the trend in the future. Because of the physiological differences among crops and their response efficiency to external changes, changes in planting structure, climate and input of production factors will have an impact on regional agricultural water use and GHG emissions. This paper systematically analyzed the spatial-temporal evolution characteristics of crop planting structure, climate, and production factor inputs in Heilongjiang Province, the main grain-producing region of China, from 2000 to 2015, and quantified the regional agricultural water use and GHG emissions characteristics under different scenarios by using the Penman-Monteith formula and the Denitrification-Decomposition (DNDC) model. The results showed that the global warming potential (GWP) increased by 15% due to the change in planting structure. A large increase in the proportion of rice and corn sown was the main reason. During the study period, regional climate change had a positive impact on the water- saving and emission reduction of the agricultural industry. The annual water demand per unit area decreased by 19%, and the GWP decreased by 12% compared with that in 2000. The input of fertilizer and other means of production will have a significant impact on GHG emissions from farmlands. The increase in N fertilizer input significantly increased N<sub>2</sub>O emissions, with a 5% increase in GWP. Agricultural water consumption and carbon emissions are affected by changes in climate, input of means of production, and planting structure. Therefore, multiple regulatory measures should be taken in combination with regional characteristics to realize a new layout of planting structure with low emissions, water conservation, and sustainability.</p>


Author(s):  
Liu Liu ◽  
Zezhong Guo ◽  
Guanhua Huang ◽  
Ruotong Wang

As the second largest inland river basin situated in the middle of the Hexi Corridor, Northwest China, the Heihe River basin (HRB) has been facing a severe water shortage problem, which seriously restricts its green and sustainable development. The evaluation of climate change impact on water productivity inferred by crop yield and actual evapotranspiration is of significant importance for water-saving in agricultural regions. In this study, the multi-model projections of climate change under the three Representative Concentration Pathways emission scenarios (RCP2.6, RCP4.5, RCP8.5) were used to drive an agro-hydrological model to evaluate the crop water productivity in the middle irrigated oases of the HRB from 2021–2050. Compared with the water productivity simulation based on field experiments during 2012–2015, the projected water productivity in the two typical agricultural areas (Gaotai and Ganzhou) both exhibited an increasing trend in the future 30 years, which was mainly attributed to the significant decrease of the crop water consumption. The water productivity in the Gaotai area under the three RCP scenarios during 2021–2050 increased by 9.2%, 14.3%, and 11.8%, while the water productivity increased by 15.4%, 21.6%, and 19.9% in the Ganzhou area, respectively. The findings can provide useful information on the Hexi Corridor and the Belt and Road to policy-makers and stakeholders for sustainable development of the water-ecosystem-economy system.


2019 ◽  
Vol 212 ◽  
pp. 378-387
Author(s):  
Shumin Han ◽  
Qiuli Hu ◽  
Yonghui Yang ◽  
Yanmin Yang ◽  
Xinyao Zhou ◽  
...  

2021 ◽  
Vol 9 ◽  
Author(s):  
Kai Huang ◽  
Mengqi Wang ◽  
Zhongren Zhou ◽  
Yajuan Yu ◽  
Yixing Bi

Beijing, the capital of China, is experiencing a serious lack of water, which is becoming a main factor in the restriction of the development of the social economy. Due to the low economic efficiency and high consumption proportion of agricultural water use, the relationship between economic growth and agricultural water use is worth investigating. The “decoupling” index is becoming increasingly popular for identifying the degree of non-synchronous variation between resource consumption and economic growth. However, few studies address the decoupling between the crop water consumption and agricultural economic growth. This paper involves the water footprint (WF) to assess the water consumption in the crop production process. After an evaluation of the crop WF in Beijing, this paper applies the decoupling indicators to examine the occurrence of non-synchronous variation between the agricultural gross domestic product (GDP) and crop WF in Beijing from 1981 to 2013. The results show that the WF of crop production in 2013 reduced by 62.1% compared to that in 1980 — in total, 1.81 × 109 m3. According to the decoupling states, the entire study period is divided into three periods. From 1981 to 2013, the decoupling states represented seventy-five percent of the years from 1981 to 1992 (Period I) with a moderate decoupling degree, more than ninety percent from 1993 to 2003 (Period II) with a very strong decoupling degree and moved from non-decoupling to strong decoupling from 2004 to 2013 (Period III). Adjusting plantation structure, technology innovation and raising awareness of water-saving, may promote the decoupling degree between WF and agricultural GDP in Beijing.


2020 ◽  
Vol 36 (1) ◽  
pp. 11-24 ◽  
Author(s):  
Vikram Kumar ◽  
Sumit Sen

HighlightsSpring flows are the primary source of water for rural Himalayan communities.An attempt was made to understand the potential of spring discharge as an alternative irrigation source.Improved management of resources is vital to account for agricultural water use.Managing water resources is a collective endeavor for achieving water security.Abstract.With increasing population and restricted water and land resources, there is a growing concern for better planning of the available water and land resources. In the mountainous regions or mountains, there is limited land with uncertain water availability as the rainfall patterns pose a major threat to the livelihood of the people. Therefore, it becomes necessary to quantify and manage the available water resources in a sustainable way. People in the Himalayas are mainly dependent on the springs for drinking water, but not much attention has been dedicated to the development and conservation of these springs. A spring in the Tehri-Garhwal district of Uttarakhand state of India, has been continuously monitored to quantify the available water for domestic use and agriculture. In this study, an attempt is made to understand the potential of a spring for agricultural water use by evaluating the crop water requirement and potential improved strategies to increase the water productivity. Analysis proves that crop evapotranspiration is higher (946-1062 mm) for crops with extended duration (165-180 days) as compared to evapotranspiration (92.91 mm) of short duration (60 days) crops. The total water requirement for major crops in the area is 6411.35 mm and the monitored spring has the potential to supplement this water requirement. Adopting the system of rice intensification to increase the rice yield (by 49%), increases the water productivity. The sensitivity analysis of benefit to cost suggests that, an increase in the crop yield by 30% can increase the revenue in the study area by Rs.3687197, which is 217% more than the input costs. Therefore, it is essential to optimize the available water and area for irrigation to achieve the global water security for increasing population. Further, utilizing springs as potential irrigation sources will support rural community in meeting domestic water requirement and achieving environmental sustainability. Findings of this study will help in planning and implementing management strategies that are resilient in the face of future changes and improve the economic condition of farmers. Keywords: Crop evapotranspiration, Himalaya, Optimization, Sensitivity analysis, Spring.


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