Crop-specific seasonal estimates of irrigation-water demand in South Asia

Abstract. Especially in the Himalayan headwaters of the main rivers in South Asia, shifts in runoff are expected as a result of a rapidly changing climate. In recent years, our insight into these shifts and their impact on water availability has increased. However, a similar detailed understanding of the seasonal pattern in water demand is surprisingly absent. This hampers a proper assessment of water stress and ways to cope and adapt. In this study, the seasonal pattern of irrigation-water demand resulting from the typical practice of multiple cropping in South Asia was accounted for by introducing double cropping with monsoon-dependent planting dates in a hydrology and vegetation model. Crop yields were calibrated to the latest state-level statistics of India, Pakistan, Bangladesh and Nepal. The improvements in seasonal land use and cropping periods lead to lower estimates of irrigation-water demand compared to previous model-based studies, despite the net irrigated area being higher. Crop irrigation-water demand differs sharply between seasons and regions; in Pakistan, winter (rabi) and monsoon summer (kharif) irrigation demands are almost equal, whereas in Bangladesh the rabi demand is ∼  100 times higher. Moreover, the relative importance of irrigation supply versus rain decreases sharply from west to east. Given the size and importance of South Asia improved regional estimates of food production and its irrigation-water demand will also affect global estimates. In models used for global water resources and food-security assessments, processes like multiple cropping and monsoon-dependent planting dates should not be ignored.

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Crop-specific seasonal estimates of irrigation water demand in South Asia

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-12-7843-2015 ◽

2015 ◽

Vol 12 (8) ◽

pp. 7843-7873 ◽

Cited By ~ 1

Author(s):

H. Biemans ◽

C. Siderius ◽

A. Mishra ◽

B. Ahmad

Keyword(s):

South Asia ◽

Irrigation Water ◽

Water Demand ◽

Crop Yields ◽

Seasonal Pattern ◽

Multiple Cropping ◽

Planting Dates ◽

Irrigation Water Demand ◽

Double Cropping ◽

Regional Estimates

Abstract. Especially in the Himalayan headwaters of the main rivers in South Asia, shifts in runoff are expected as a result of a rapidly changing climate. In recent years, our insight in these shifts and their impact on water availability has increased. However, a similar detailed understanding of the seasonal pattern in water demand is surprisingly absent. This hampers a proper assessment of water stress and ways to cope and adapt. In this study, the seasonal pattern of irrigation water demand resulting from the typical practice of multiple-cropping in South Asia was accounted for by introducing double-cropping with monsoon-dependent planting dates in a hydrology and vegetation model. Crop yields were calibrated to the latest subnational statistics of India, Pakistan, Bangladesh and Nepal. The representation of seasonal land use and more accurate cropping periods lead to lower estimates of irrigation water demand compared to previous model-based studies, despite the net irrigated area being higher. Crop irrigation water demand differs sharply between seasons and regions; in Pakistan, winter (Rabi) and summer (Kharif) irrigation demands are almost equal, whereas in Bangladesh the Rabi demand is ~ 100 times higher. Moreover, the relative importance of irrigation supply vs. rain decreases sharply from west to east. Given the size and importance of South Asia, improved regional estimates of food production and its irrigation water demand will also affect global estimates. In models used for global water resources and food-security assessments, processes like multiple-cropping and monsoon-dependent planting dates should not be ignored.

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The Impacts of Climate Variability on Crop Yields and Irrigation Water Demand in South Asia

Water ◽

10.3390/w13010050 ◽

2020 ◽

Vol 13 (1) ◽

pp. 50

Author(s):

Qurat-ul-Ain Ahmad ◽

Hester Biemans ◽

Eddy Moors ◽

Nuzba Shaheen ◽

Ilyas Masih

Keyword(s):

South Asia ◽

Irrigation Water ◽

Water Demand ◽

Crop Yields ◽

Grid Cell ◽

River Basins ◽

Climate Variables ◽

Irrigation Water Demand ◽

Spatio Temporal ◽

Study Sites

Accurate (spatio-temporal) estimation of the crop yield relation to climate variables is essential in the densely populated Indus, Ganges, and Brahmaputra (IGB) river basins of South Asia for devising appropriate adaptation strategies to ensure regional food and water security. This study examines wheat (Triticum aestivum) and rice (Oryza sativa) crop yields’ sensitivity to primary climate variables (i.e., temperature and precipitation) and related changes in irrigation water demand at different spatial (i.e., province/state, districts and grid cell) and temporal (i.e., seasonal and crop growth phase) scales. To estimate the climate driven variations in crop yields, observed and modelled data applying the Lund-Potsdam-Jena managed Land (LPJmL) model are used for six selected study sites in the IGB river basins over the period 1981–2010. Our statistical analysis underscores the importance of impacts assessments at higher spatio-temporal scales. Our grid cell (aggregated over study sites) scale analysis shows that 27–72% variations in wheat and 17–55% in rice crop yields are linked with temperature variations at a significance level of p < 0.001. In the absence of irrigation application, up to 39% variations in wheat and up to 75% variations in rice crop yields are associated with precipitation changes in all study sites. Whereas, observed crop yields show weak correlations with temperature at a coarser resolution, i.e., up to 4% at province and up to 31% at district scales. Crop yields also showed stronger sensitivity to climate variables at higher temporal scale (i.e., vegetative and reproductive phases) having statistically strong negative relationship with temperature and positive with precipitation during the reproductive phase. Similarly, crop phase-specific variations in climate variables have considerable impacts (i.e., quantity and timing) on irrigation water demand. For improved crop water planning, we suggest integrated climate impact assessments at higher spatio-temporal scales which can help to devise appropriate adaptation strategies for sustaining future food demand.

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Quantifying the Impacts of Compound Extremes on Agriculture and Irrigation Water Demand

10.5194/hess-2020-275 ◽

2020 ◽

Author(s):

Iman Haqiqi ◽

Danielle S. Grogan ◽

Thomas W. Hertel ◽

Wolfram Schlenker

Keyword(s):

Heat Stress ◽

Water Stress ◽

Irrigation Water ◽

Water Demand ◽

Crop Production ◽

Crop Yields ◽

Fold Increase ◽

The United States ◽

Food Prices ◽

Irrigation Water Demand

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.

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Shifts in Irrigation Water Demand and Supply Patterns during Critical Crop Growth Stages under Changing Impacts of Climate and Socio-Economic Dynamics in South Asia

10.1002/essoar.10502105.1 ◽

2020 ◽

Author(s):

Qurat UL AIN Ahmad ◽

Eddy Moors ◽

Nuzba Shaheen ◽

Hester Biemans ◽

Ilyas Masih ◽

...

Keyword(s):

South Asia ◽

Irrigation Water ◽

Water Demand ◽

Crop Growth ◽

Growth Stages ◽

Economic Dynamics ◽

Demand And Supply ◽

Irrigation Water Demand ◽

Water Demand And Supply ◽

Crop Growth Stages

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Minimizing irrigation water demand: An evaluation of shifting planting dates in Sri Lanka

AMBIO ◽

10.1007/s13280-017-0993-8 ◽

2017 ◽

Vol 47 (4) ◽

pp. 466-476 ◽

Cited By ~ 2

Author(s):

Ashley Rivera ◽

Thushara Gunda ◽

George M. Hornberger

Keyword(s):

Sri Lanka ◽

Irrigation Water ◽

Water Demand ◽

Planting Dates ◽

Irrigation Water Demand

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Shifts in Irrigation Water Demand and Supply Pattern During Sensitive Crop Growth Phases in South Asia

SSRN Electronic Journal ◽

10.2139/ssrn.3969074 ◽

2021 ◽

Author(s):

QURAT UL AIN Ahmad ◽

Eddy Moors ◽

Hester Biemans ◽

Nuzba Shaheen ◽

Ilyas Masih ◽

...

Keyword(s):

South Asia ◽

Irrigation Water ◽

Water Demand ◽

Crop Growth ◽

Growth Phases ◽

Demand And Supply ◽

Irrigation Water Demand ◽

Water Demand And Supply ◽

Supply Pattern

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An Innovative Fog Catcher System Applied in the Andean Communities of Ecuador

Transactions of the ASABE ◽

10.13031/trans.12368 ◽

2017 ◽

Vol 60 (6) ◽

pp. 1917-1923

Author(s):

David V. Carrera-Villacrés ◽

Iveth Carolina Robalino ◽

Fabian F. Rodríguez ◽

Washington R. Sandoval ◽

Deysi L. Hidalgo ◽

...

Keyword(s):

Sea Level ◽

Water Deficit ◽

Irrigation Water ◽

Water Demand ◽

Agricultural Production ◽

Water Deficits ◽

Irrigation Water Demand ◽

The World ◽

Precipitation Water ◽

Local Water

Abstract. Fog catchers have been successfully applied in several countries around the world. In Ecuador, the Galte communities in the Andean region suffer from water deficits because they are located at an altitude higher than 3500 m above sea level. Rainfall in the area is relatively low, about 600 mm per year, with high evapotranspiration of approximately 615.74 mm per year. This study aimed to install fog catchers in Galte in 2014 and 2015 to help meet the communities’ water needs. The fog catcher system was designed to satisfy the irrigation water demand for local agricultural production, mainly maize, based on estimates using the Blaney-Criddle method. Every day throughout the year, each fog catcher collected 5 to 20 L of water per m2 of catcher area. The results indicate that the fog catcher system can meet about 5% of the local water demand for agricultural production. Keywords: Ecuador, Evaporation, Evapotranspiration, Precipitation, Water deficit.

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Potential for sustainable irrigation expansion in a 3 °C warmer climate

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2017796117 ◽

2020 ◽

Vol 117 (47) ◽

pp. 29526-29534

Author(s):

Lorenzo Rosa ◽

Davide Danilo Chiarelli ◽

Matteo Sangiorgio ◽

Areidy Aracely Beltran-Peña ◽

Maria Cristina Rulli ◽

...

Keyword(s):

Climate Change ◽

Irrigation Water ◽

Water Demand ◽

Crop Production ◽

Cropping Systems ◽

Water Storage ◽

Future Research ◽

Irrigation Water Demand ◽

Starting Point ◽

Sustainable Irrigation

Climate change is expected to affect crop production worldwide, particularly in rain-fed agricultural regions. It is still unknown how irrigation water needs will change in a warmer planet and where freshwater will be locally available to expand irrigation without depleting freshwater resources. Here, we identify the rain-fed cropping systems that hold the greatest potential for investment in irrigation expansion because water will likely be available to suffice irrigation water demand. Using projections of renewable water availability and irrigation water demand under warming scenarios, we identify target regions where irrigation expansion may sustain crop production under climate change. Our results also show that global rain-fed croplands hold significant potential for sustainable irrigation expansion and that different irrigation strategies have different irrigation expansion potentials. Under a 3 °C warming, we find that a soft-path irrigation expansion with small monthly water storage and deficit irrigation has the potential to expand irrigated land by 70 million hectares and feed 300 million more people globally. We also find that a hard-path irrigation expansion with large annual water storage can sustainably expand irrigation up to 350 million hectares, while producing food for 1.4 billion more people globally. By identifying where irrigation can be expanded under a warmer climate, this work may serve as a starting point for investigating socioeconomic factors of irrigation expansion and may guide future research and resources toward those agricultural communities and water management institutions that will most need to adapt to climate change.

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