Your search found 15 records
1 Gumma, M. K.; Thenkabail, P. S.; Barry, Boubacar. 2010. Delineating shallow ground water irrigated areas in the Atankwidi Watershed (Northern Ghana, Burkina Faso) using Quickbird 0.61 - 2.44 meter data. African Journal of Environmental Science and Technology, 4(7):455-464.
Groundwater irrigation ; Irrigated sites ; Watersheds ; River basins ; Remote sensing ; Land use ; Land cover ; Wells ; Satellite imagery / West Africa / Ghana / Burkina Faso / Volta River Basin / Atankwidi Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H043080)
http://www.academicjournals.org/AJEST/PDF/pdf%202010/Jul/Krishna%20et%20al.pdf
https://vlibrary.iwmi.org/pdf/H043080.pdf
https://vlibrary.iwmi.org/pdf/H043080.pdf
(1.38 MB)
The major goal of this research was to delineate the shallow groundwater irrigated areas (SGI) in the Atankwidi Watershed in the Volta River Basin of West Africa. Shallow ground water irrigation is carried out using very small dug-wells all along the river banks or shallow dug-outs all along the river bed. Each of these dug-wells and dug-outs are highly fragmented small water bodies that irrigate only a fraction of an acre. However, these are contiguous dug-wells and dug-outs that are hundreds or thousands in number. Very high spatial resolution (VHSR) Quickbird imagery (0.61 to 2.44 m) was used to identify: (a) dug-wells that hold small quantities of water in otherwise dry stream; and (b) dug-outs that are just a meter or two in depth but have dug-out soils that are dumped just next to each well. The Quickbird VHSR imagery was found ideal to detect numerous: (i) dug-wells through bright soils that lay next to each dug-well, and (ii) water bodies all along the dry stream bed. We used fusion of 0.61 m Quickbird panchromatic data with 2.44 Quickbird multispectral data to highlight SGI and delineate their boundaries. Once this was achieved, classification techniques using Quickbird imagery was used within the delineated areas to map SGI and other land use/land cover (LULC) areas. Results obtained showed that SGI is practiced on a land area of 387 ha (1.4%), rainfed areas is 15638 ha (54.7%) and the remaining area in other LULC. These results were verified using field-plot data which showed an accuracy of 92% with errors of omissions and commissions less than 10%.
2 Venot, Jean-Philippe; Jella, Kiran; Bharati, Luna; George, B.; Biggs, T.; Gangadhara Rao, Parthasaradhi; Gumma, M. K.; Acharya, Sreedhar. 2010. Farmers' adaptation and regional land use changes in irrigation systems under fluctuating water supply, South India. Journal of Irrigation and Drainage Engineering, 136(9):595-609. [doi: https://doi.org/10.1061/(ASCE)IR.1943-4774.0000225]
Irrigation systems ; Irrigation programs ; Water shortage ; Water scarcity ; Water availability ; River basins ; Crop management ; Productivity / India / Nagarjuna Sagar Project
(Location: IWMI HQ Call no: PER Record No: H043081)
(2.46 MB)
In closing river basins where nearly all available water is committed to existing uses, downstream irrigation projects are expected to experience water shortages more frequently. Understanding the scope for resilience and adaptation of large surface irrigation systems is vital to the development of management strategies designed to mitigate the impact of river basin closure on food production and the livelihoods of farmers. A multi-level analysis (farm level surveys and regional assessment through remote sensing techniques and statistics) of the dynamics of irrigation and land use in the Nagarjuna Sagar project (South India) in times of changing water availability (2000–2006) highlights that during low flow years, there is large-scale adoption of rainfed —or supplementary irrigated- crops that have lower land productivity but higher water productivity, and that a large fraction of land is fallowed. Cropping pattern changes during the drought reveal short term coping strategies rather than long-term evolutions: after the shock, farmers reverted to their usual cropping patterns during years with adequate canal supplies. For the sequence of water supply fluctuations observed from 2000–2006, the Nagarjuna Sagar irrigation system shows a high level of sensitivity to short-term perturbations, but long-term resilience if flows recover. Management strategies accounting for local level adaptability will be necessary to mitigate the impacts of low flow years but there is scope for improvement of the performance of the system.
3 Fujii, H.; Gumma, M. K.; Thenkabail, P. S.; Namara, Regassa E. 2010. Suitability evaluation for lowland rice in inland valleys in West Africa. In Japanese. Transactions of the Japanese Society of Irrigation, Drainage and Rural Engineering, 78(4):47-55.
(Location: IWMI HQ Call no: e-copy only Record No: H043176)
(2.83 MB)
A GIS based model developed by the authors are applied for selecting suitable rice cultivation area in inland valleys that has high potential for rice production in West Africa where rice consumption is increasing very rapidly. The model has the following features. 1. The model is to evaluate the suitability of the land for lowland rice based on score distribution maps respectively made by the data of 29 evaluation parameters. 2. The parameters are classified into 4 categories; bio-physical, technical, socio-economic and health-environmental parameters. 3. Each scored map(layer)is integrated to obtain total scores by multiplying a weight which is determined by the importance of parameters. The suitability for rice in two study sites was evaluated using the model. Mankran and Jolo-Kwaha watershed selected as the study sites from different agro-ecological zone in Ghana. Applying the data of 12 parameters acquired in the study sites to the model, “very suitable” or “suitable” occupies around 30% in Mankran study site and around 60% in Jolo-Kwaha study site.
4 Gumma, M. K.; Thenkabail, P. S.; Nelson, A. 2011. Mapping irrigated areas using MODIS 250 meter time-series data: a study on Krishna River Basin (India) Water, 3(1):113-131. [doi: https://doi.org/10.3390/w3010113]
Groundwater irrigation ; Surface irrigation ; Irrigated sites ; Mapping ; Land use ; Land cover ; Remote sensing ; Models ; Time series analysis ; River basins / India / Krishna River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H043483)
(3.70 MB)
Mapping irrigated areas of a river basin is important in terms of assessing water use and food security. This paper describes an innovative remote sensing based vegetation phenological approach to map irrigated areas and then the differentiates the ground water irrigated areas from the surface water irrigated areas in the Krishna river basin (26,575,200 hectares) in India using MODIS 250 meter every 8-day near continuous time-series data for 2000–2001. Temporal variations in the Normalized Difference Vegetation Index (NDVI) pattern obtained in irrigated classes enabled demarcation between: (a) irrigated surface water double crop, (b) irrigated surface water continuous crop, and (c) irrigated ground water mixed crops. The NDVI patterns were found to be more consistent in areas irrigated with ground water due to the continuity of water supply. Surface water availability, on the other hand, was dependent on canal water release that affected time of crop sowing and growth stages, which was in turn reflected in the NDVI pattern. Double cropped and light irrigation have relatively late onset of greenness, because they use canal water from reservoirs that drain large catchments and take weeks to fill. Minor irrigation and ground water irrigated areas have early onset of greenness because they drain smaller catchments where aquifers and reservoirs fill more quickly. Vegetation phonologies of 9 distinct classes consisting of Irrigated, rainfed, and other land use classes were also derived using MODIS 250 meter near continuous time-series data that were tested and verified using groundtruth data, Google Earth very high resolution (sub-meter to 4 meter) imagery, and state-level census data. Fuzzy classification accuracies for most classes were around 80% with class mixing mainly between various irrigated classes. The areas estimated from MODIS were highly correlated with census data (R-squared value of 0.86).
5 Barry, Boubacar; Kortatsi, B.; Forkuor, G.; Gumma, M. K.; Namara, Regassa E.; Rebelo, Lisa-Maria; van den Berg, J.; Laube, W. 2010. Shallow groundwater in the Atankwidi Catchment of the White Volta Basin: current status and future sustainability. Colombo, Sri Lanka: International Water Management Institute (IWMI). 23p. (IWMI Research Report 139) [doi: https://doi.org/10.5337/2010.234]
Groundwater irrigation ; Aquifers ; River basins ; Catchment areas ; Irrigation practices ; Remote sensing ; Mapping / Ghana / Atankwidi Catchment / White Volta River Basin
(Location: IWMI HQ Call no: IWMI 333.9104 G200 BAR Record No: H043521)
(1.39 MB)
The Atankwidi Catchment, which lies in the White Volta Basin in West Africa, is intensively cultivated by locals for economic gains. During dry seasons, farmers irrigate their crops, chiefly tomatoes, using shallow groundwater harvested from shallow ponds they dig using simple tools like an axe, hoe, bucket and bowls. Recent expansion in cultivated areas has brought to the fore the need to estimate the volume of shallow groundwater stored in the catchment’s underlying aquifer and to what extent it can sustain the incremental growth in irrigated areas.
6 Gumma, M. K.; Thenkabail, P. S.; Muralikrishna. I. V.; Velpuri, M. N.; Gangadhara Rao, Parthasaradhi; Dheeravath, V.; Biradar, C. M.; Acharya, N. Sreedhar; Gaur, A. 2011. Changes in agricultural cropland areas between a water-surplus year and a water-deficit year impacting food security, determined using MODIS 250 m time-series data and spectral matching techniques, in the Krishna River basin (India). International Journal of Remote Sensing, 32(12):3495-3520. [doi: https://doi.org/10.1080/01431161003749485]
Agricultural land ; Farmland ; Water availability ; Water use ; Water deficit ; Food security ; Models ; River basins ; Rain ; Rainfed farming ; Irrigated land ; Land use ; Land cover ; Climate change ; Satellite imagery ; Mapping ; Time series analysis ; Spectral analysis / India / Krishna River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H043968)
(1.46 MB)
The objective of this study was to investigate the changes in cropland areas as a result of water availability using Moderate Resolution Imaging Spectroradiometer (MODIS) 250 m time-series data and spectral matching techniques (SMTs). The study was conducted in the Krishna River basin in India, a very large river basin with an area of 265 752 km2 (26 575 200 ha), comparing a water-surplus year (2000–2001) and a water-deficit year (2002–2003). The MODIS 250 m time-series data and SMTs were found ideal for agricultural cropland change detection over large areas and provided fuzzy classification accuracies of 61–100% for various land-use classes and 61–81% for the rain-fed and irrigated classes. The most mixing change occurred between rain-fed cropland areas and informally irrigated (e.g. groundwater and small reservoir) areas. Hence separation of these two classes was the most difficult. The MODIS 250 m-derived irrigated cropland areas for the districts were highly correlated with the Indian Bureau of Statistics data, with R2-values between 0.82 and 0.86. The change in the net area irrigated was modest, with an irrigated area of 8 669 881 ha during the water-surplus year, as compared with 7 718 900 ha during the water-deficit year. However, this is quite misleading as most of the major changes occurred in cropping intensity, such as changing from higher intensity to lower intensity (e.g. from double crop to single crop). The changes in cropping intensity of the agricultural cropland areas that took place in the water-deficit year (2002–2003) when compared with the water-surplus year (2000–2001) in the Krishna basin were: (a) 1 078 564 ha changed from double crop to single crop, (b) 1 461 177 ha changed from continuous crop to single crop, (c) 704 172 ha changed from irrigated single crop to fallow and (d) 1 314 522 ha changed from minor irrigation (e.g. tanks, small reservoirs) to rain-fed. These are highly significant changes that will have strong impact on food security. Such changes may be expected all over the world in a changing climate.
7 Gumma, M. K.; Thenkabail, P. S.; Hideto, F.; Nelson, A.; Dheeravath, V.; Busia, D.; Rala, A. 2011. Mapping irrigated areas of Ghana using fusion of 30 m and 250 m resolution remote-sensing data. Remote Sensing, 3(4):816-835. [doi: https://doi.org/10.3390/rs3040816]
Remote sensing ; Methodology ; Mapping ; Irrigated land ; Irrigated farming ; Land use ; Land cover ; Satellite imagery ; Statistics / Ghana
(Location: IWMI HQ Call no: e-copy only Record No: H044267)
(1.69MB)
Maps of irrigated areas are essential for Ghana’s agricultural development. The goal of this research was to map irrigated agricultural areas and explain methods and protocols using remote sensing. Landsat Enhanced Thematic Mapper (ETM+) data and time-series Moderate Resolution Imaging Spectroradiometer (MODIS) data were used to map irrigated agricultural areas as well as other land use/land cover (LULC) classes, for Ghana. Temporal variations in the normalized difference vegetation index (NDVI) pattern obtained in the LULC class were used to identify irrigated and non-irrigated areas. First, the temporal variations in NDVI pattern were found to be more consistent in long-duration irrigated crops than with short-duration rainfed crops due to more assured water supply for irrigated areas. Second, surface water availability for irrigated areas is dependent on shallow dug-wells (on river banks) and dug-outs (in river bottoms) that affect the timing of crop sowing and growth stages, which was in turn reflected in the seasonal NDVI pattern. A decision tree approach using Landsat 30 m one time data fusion with MODIS 250 m time-series data was adopted to classify, group, and label classes. Finally, classes were tested and verified using ground truth data and national statistics. Fuzzy classification accuracy assessment for the irrigated classes varied between 67 and 93%. An irrigated area derived from remote sensing (32,421 ha) was 20–57% higher than irrigated areas reported by Ghana’s Irrigation Development Authority (GIDA). This was because of the uncertainties involved in factors such as: (a) absence of shallow irrigated area statistics in GIDA statistics, (b) non-clarity in the irrigated areas in its use, under-development, and potential for development in GIDA statistics, (c) errors of omissions and commissions in the remote sensing approach, and (d) comparison involving widely varying data types, methods, and approaches used in determining irrigated area statistics using GIDA and remote sensing. Extensive field campaigns to help in better classification and validation of irrigated areas using high (30 m ) to very high (<5 m) resolution remote sensing data that are fused with multi temporal data like MODIS are the way forward. This is especially true in accounting for small yet contiguous patches of irrigated areas from dug-wells and dug-outs.
8 Pavelic, Paul; Patankar, U.; Acharya, Sreedhar; Jella, Kiran; Gumma, M. K.. 2012. Role of groundwater in buffering irrigation production against climate variability at the basin scale in South-West India. Agricultural Water Management, 103(1):78-87. [doi: https://doi.org/10.1016/j.agwat.2011.10.01]
Groundwater irrigation ; Wells ; Resource depletion ; Aquifers ; Climate change ; River basins ; Rain ; Hydrology ; Water scarcity ; Water stress ; Water scarcity / India / Upper Bhima River Basin
(Location: IWMI HQ Call no: PER Record No: H044570)
(2.01 MB)
The basaltic aquifers of the Upper Bhima River Basin in India are highly utilized for irrigation but the sustainability of groundwater withdrawals and the agricultural production systems they support is largely unknown. Here we used hydrogeological data, supported by secondary data, to assess the effects of water scarcity over a decade-long period (1998–2007) on the groundwater resources at the regional basin scale. This reveals no evidence of systematic declines in total groundwater availability over the period; only shorter-term losses/gains in storage associated with successive dry/wet years. The clearest indicator of stress comes from the more widespread drying out of wells following lower rainfall years throughout the basin and especially in upland areas where aquifers are least developed and most easily drained. Groundwater in the basin offers an adaptive mechanism to climate variability to some degree, but the buffering capacity is constrained by low aquifer storativity and average residence times of just a few years. Around 40% of the basin is currently at a level of development that is of concern, and the number of irrigation wells is growing rapidly. However recent evidence of conversion from high to low water use crops indicates the adaptive capacity of farmers to water-related stresses. Surplus surface water ows may provide opportunities to enhance groundwater recharge but requires careful trade-off analysis of the downstream impacts.
9 Gumma, M. K.; Pavelic, Paul. 2013. Mapping of groundwater potential zones across Ghana using remote sensing, geographic information systems, and spatial modeling. Environmental Monitoring and Assessment, 185(4):3561-3579. [doi: https://doi.org/ 10.1007/s10661-012-2810-y]
Groundwater potential ; Groundwater development ; GIS ; Remote sensing ; Models ; Aquifers ; Rain ; Geomorphology ; Drainage systems ; Land use ; Soils / Ghana
(Location: IWMI HQ Call no: e-copy only Record No: H045030)
(3.67 MB)
Groundwater development across much of sub-Saharan Africa is constrained by a lack of knowledge on the suitability of aquifers for borehole construction. The main objective of this study was to map groundwater potential at the country-scale for Ghana to identify locations for developing new supplies that could be used for a range of purposes. Groundwater potential zones were delineated using remote sensing and geographical information system (GIS) techniques drawing from a database that includes climate, geology, and satellite data. Subjective scores and weights were assigned to each of seven key spatial data layers and integrated to identify groundwater potential according to five categories ranging from very good to very poor derived from the total percentage score. From this analysis, areas of very good groundwater potential are estimated to cover 689,680 ha (2.9 % of the country), good potential 5,158,955 ha (21.6 %), moderate potential 10,898,140 ha (45.6 %), and poor/very poor potential 7,167,713 ha (30 %). The results were independently tested against borehole yield data (2,650 measurements) which conformed to the anticipated trend between groundwater potential and borehole yield. The satisfactory delineation of groundwater potential zones through spatial modeling suggests that groundwater development should first focus on areas of the highest potential. This study demonstrates the importance of remote sensing and GIS techniques in mapping groundwater potential at the country-scale and suggests that similar methods could be applied across other African countries and regions.
10 Gumma, M. K.; Kajisa, K.; Mohammed, I. A.; Whitbread, A. M.; Nelson, A.; Rala, A.; Kuppannan, Palanisami. 2015. Temporal change in land use by irrigation source in Tamil Nadu and management implications. Environmental Monitoring and Assessment, 187(1):1-17. [doi: https://doi.org/10.1007/s10661-014-4155-1]
Land use ; Land cover ; Groundwater irrigation ; Irrigated sites ; Irrigation canals ; Tank irrigation ; Spectral analysis ; Rain ; Crop management ; River basins ; Agriculture ; Remote sensing / India / Tamil Nadu
(Location: IWMI HQ Call no: e-copy only Record No: H047509)
(6.45 MB)
Interannual variation in rainfall throughout Tamil Nadu has been causing frequent and noticeable land use changes despite the rapid development in groundwater irrigation. Identifying periodically water-stressed areas is the first and crucial step to minimizing negative effects on crop production. Such analysis must be conducted at the basin level as it is an independent water accounting unit. This paper investigates the temporal variation in irrigated area between 2000–2001 and 2010–2011 due to rainfall variation at the state and sub-basin level by mapping and classifying Moderate Resolution Imaging Spectroradiometer (MODIS) 8-day composite satellite imagery using spectral matching techniques. A land use/land cover map was drawn with an overall classification accuracy of 87.2 %. Area estimates between the MODISderived net irrigated area and district-level statistics (2000–2001 to 2007–2008) were in 95 % agreement. A significant decrease in irrigated area (30–40 %) was observed during the water-stressed years of 2002–2003, 2003–2004, and 2009–2010. Major land use changes occurred three times during 2000 to 2010. This study demonstrates how remote sensing can identify areas that are prone to repeated land use changes and pin-point key target areas for the promotion of drought-tolerant varieties, alternativewater management practices, and new cropping patterns to ensure sustainable agriculture for food security and livelihoods.
11 Mottaleb, K. A.; Gumma, M. K.; Mishra, A. K.; Mohanty, S. 2015. Quantifying production losses due to drought and submergence of rainfed rice at the household level using remotely sensed MODIS data. Agricultural Systems, 137:227-235. [doi: https://doi.org/10.1016/j.agsy.2014.08.014]
Rainfed farming ; Rice ; Crop production ; Crop losses ; Drought ; Submergence ; Remote sensing ; Satellite surveys ; Models ; Seasonal cropping ; Households ; Farm income ; Expenditure ; Case studies / Bangladesh
(Location: IWMI HQ Call no: e-copy only Record No: H047576)
(0.88 MB)
Combining remotely sensed Moderate Resolution Imaging Spectroradiometer (MODIS) data with Bangladesh Household Income and Expenditure Survey (HIES) data, this study estimates losses in rainfed rice production at the household level. In particular, we estimated the rice areas affected by drought and submergence from remotely sensed MODIS data and rice production from Household Income and Expenditure Survey (HIES) data for 2000, 2005 and 2010. Applying two limit Tobit estimation method, this study demonstrated that both drought and submergence significantly affected rice production. Findings reveal that on average, a one percent increase in drought affected area at district level reduces Aman season rice production by approximately 1382 kilograms per household on average, annually. Similarly, a one percent increase in drought area reduces rainfed Aus season rice production by approximately 693 kilograms per household, on average, annually. Based on the findings the paper suggests disseminating and developing drought and submergence tolerant rice and also short duration rice varieties to minimize loss caused by drought and submergence in Aus and Aman rice seasons.
12 Ahmed, I. M.; Gumma, M. K.; Kumar, S.; Craufurd, P.; Rafi, I. M.; Haileslassie, Amare. 2016. Land use and agricultural change dynamics in SAT watersheds of southern India. Current Science, 110(9):1704-1709.
Land use ; Land cover change ; Agriculture ; Watersheds ; Farmland ; Living standards ; Water harvesting ; Water scarcity ; Water levels ; Water availability ; Local communities ; Ecosystem services ; Arid zones ; Groundwater irrigation ; Groundwater recharge ; Living standards ; Satellite imagery ; Farmers ; Rain / India
(Location: IWMI HQ Call no: e-copy only Record No: H047541)
(3.59 MB)
Impact of dynamic land use and land cover changes on the livelihood of local communities and ecosystem services is a major concern. This is particularly evident in most dryland agricultural systems in South Asia. We study land use/land cover (LULC) changes over the last two decades in a watershed (9589 ha) located in semi-arid eco-region in South India (Anantapuram district) using Landsat and IRS imagery. We captured additional data through field observations and focused group discussions. The high resolution 30 m data and the spectral matching techniques (SMTs) provided accuracy of 91–100% for various land use classes and 80–95% for the rice and groundnut areas. The watershed studied has undergone significant land use changes between 1988 and 2012. Diminishing size and number of surface water bodies, and contrastingly increased areas under irrigation clearly explain that the system has evolved significantly towards groundwater-irrigated groundnut production. Such changes could be beneficial in the short run, but if the groundwater withdrawal is without sufficient recharge, the long-term consequences on livelihoods could be negative. The water scarcity could be aggravated under the climate change. The construction of checkdams and dugout ponds to recharge groundwater is a potential solution to enhance recharge.
13 Gumma, M. K.; Mohammad, I.; Nedumaran, S.; Whitbread, A.; Lagerkvist, C. J. 2017. Urban sprawl and adverse impacts on agricultural land: a case study on Hyderabad, India. Remote Sensing, 9(11):1-16. [doi: https://doi.org/10.3390/rs9111136]
Agricultural land management ; Urban agriculture ; Periurban areas ; Land use ; Land cover change ; Wastewater irrigation ; Satellite imagery ; Spatial distribution ; Mapping ; Farmland ; Case studies / India / Hyderabad
(Location: IWMI HQ Call no: e-copy only Record No: H048409)
(13.9 MB)
Many Indian capitals are rapidly becoming megacities due to industrialization and rural–urban emigration. Land use within city boundaries has changed dynamically, accommodating development while replacing traditional land-use patterns. Using Landsat-8 and IRS-P6 data, this study investigated land-use changes in urban and peri-urban Hyderabad and their influence on land-use and land-cover. Advanced methods, such as spectral matching techniques with ground information were deployed in the analysis. From 2005 to 2016, the wastewater-irrigated area adjacent to the Musi river increased from 15,553 to 20,573 hectares, with concurrent expansion of the city boundaries from 38,863 to 80,111 hectares. Opportunistic shifts in land-use, especially related to wastewater-irrigated agriculture, emerged in response to growing demand for fresh vegetables and urban livestock feed, and to easy access to markets due to the city’s expansion. Validation performed on the land-use maps developed revealed 80–85% accuracy.
14 Birhanu, B. Z.; Traore, K.; Gumma, M. K.; Badolo, F.; Tabo, R.; Whitbread, A. M. 2019. A watershed approach to managing rainfed agriculture in the semiarid region of southern Mali: integrated research on water and land use. Environment, Development and Sustainability, 21(5):2459-2485. [doi: https://doi.org/10.1007/s10668-018-0144-9]
Rainfed farming ; Watershed management ; Participatory management ; Water use ; Water conservation ; Soil conservation ; Contour bunding ; Runoff water ; Soil moisture ; Satellite imagery ; Land use ; Land cover mapping ; Semiarid zones ; Agricultural productivity ; Economic analysis ; Stakeholders ; Development programmes / Mali / Kani Watershed
(Location: IWMI HQ Call no: e-copy only Record No: H048703)
https://link.springer.com/content/pdf/10.1007%2Fs10668-018-0144-9.pdf
https://vlibrary.iwmi.org/pdf/H048703.pdf
https://vlibrary.iwmi.org/pdf/H048703.pdf
(5.40 MB) (5.40 MB)
Soil and water conservation (SWC) practices like that of erosion control and soil fertility measures were commonly practiced in the semiarid region of southern Mali since the 1980s. The SWC practices were mainly meant to increase water availability in the subsurface, reduce farm water runoff and gully formation and improve nutrient content of the soil, thereby increasing crop yield. Despite such efforts to promote at scale SWC practices, the landscape of southern Mali is still affected by high rates of runoff and soil erosion and low crop yield in farmers’ fields. Data are lacking on previous beneficial SWC practices that could be adapted for wider application. In this paper, a watershed approach to managing rainfed agriculture is presented to show potential benefits of SWC practices at field and watershed scales. The approach included (1) community participation in establishing and monitoring new sets of hydro-meteorological monitoring stations and field experiments; (2) studying the dynamics and consumptive water uses of different land uses over time; and (3) evaluating the biophysical and economic advantages of SWC practices implemented in the watershed. Results showed that over a period of 34 years (1980–2014) cropping area and consumptive water uses of crops (sorghum and cotton) increased at the expenses of natural vegetation. However, the yield of these crops remained low, indicating that soil fertility management and soil moisture were insufficient. In such cases, implementation of more SWC practices can help provide the additional soil moisture required.
15 Owusu, Afua; Kagone, S.; Leh, Mansoor; Velpuri, Naga Manohar; Gumma, M. K.; Ghansah, Benjamin; Thilina-Prabhath, Paranamana; Akpoti, Komlavi; Mekonnen, Kirubel; Tinonetsana, Primrose; Mohammed, I. 2024. A framework for disaggregating remote-sensing cropland into rainfed and irrigated classes at continental scale. International Journal of Applied Earth Observation and Geoinformation, 126:103607. [doi: https://doi.org/10.1016/j.jag.2023.103607]
Farmland ; Remote sensing ; Irrigated farming ; Rainfed farming ; Frameworks ; Agricultural water management ; Land use ; Land cover ; Models ; Datasets / Africa
(Location: IWMI HQ Call no: e-copy only Record No: H052552)
https://www.sciencedirect.com/science/article/pii/S1569843223004314/pdfft?md5=83620252268d54a0c1e63640065278cd&pid=1-s2.0-S1569843223004314-main.pdf
https://vlibrary.iwmi.org/pdf/H052552.pdf
https://vlibrary.iwmi.org/pdf/H052552.pdf
(11.90 MB) (11.9 MB)
Agriculture consumes the largest share of freshwater globally; therefore, distinguishing between rainfed and irrigated croplands is essential for agricultural water management and food security. In this study, a framework incorporating the Budyko model was used to differentiate between rainfed and irrigated cropland areas in Africa for eight remote sensing landcover products and a high-confidence cropland map (HCCM). The HCCM was generated for calibration and validation of the crop partitioning framework as an alternative to individual cropland masks which exhibit high disagreement. The accuracy of the framework in partitioning the HCCM was evaluated using an independent validation dataset, yielding an overall accuracy rate of 73 %. The findings of this study indicate that out of the total area covered by the HCCM (2.36 million km2 ), about 461,000 km2 (19 %) is irrigated cropland. The partitioning framework was applied on eight landcover products, and the extent of irrigated areas varied between 19 % and 30 % of the total cropland area. The framework demonstrated high precision and specificity scores, indicating its effectiveness in correctly identifying irrigated areas while minimizing the misclassification of rainfed areas as irrigated. This study provides an enhanced understanding of rainfed and irrigation patterns across Africa, supporting efforts towards achieving sustainable and resilient agricultural systems. Consequently, the approach outlined expands on the suite of remote sensing landcover products that can be used for agricultural water studies in Africa by enabling the extraction of irrigated and rainfed cropland data from landcover products that do not have disaggregated cropland classes.
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