Papers by Ali Ajaz
Sustainability, 2020
Groundwater depletion is a serious issue in the southern and central parts of the High Plains Aqu... more Groundwater depletion is a serious issue in the southern and central parts of the High Plains Aquifer (HPA), USA. A considerable imbalance exists between the recharge process and groundwater extractions in these areas, which threatens the long-term sustainability of the aquifer. Irrigated agriculture has a major share in the economy, and it requires high pumping rates in regions vulnerable to large groundwater level declines. A literature review has been conducted to understand the state of affairs of irrigated agriculture in the HPA, along with the dynamics of groundwater decline and recharge using statistical and remote-sensing based datasets. Also, three irrigation management and technology-based approaches have been discussed from the perspective of sustainability. The southern and central parts of the HPA consist mostly of non-renewable groundwater formations, and the natural water storage is prone to exhaustion. Moreover, the aforementioned regions have comparatively higher cr...
Identifying barriers to adoption of irrigation scheduling tools in Rio Grande Basin, 2021
Irrigated agriculture in the Rio Grande region faces water management related challenges due to c... more Irrigated agriculture in the Rio Grande region faces water management related challenges due to climate variability and rise in non-agricultural water demand. Scientific irrigation scheduling (SIS) tools allow growers to optimize the water use and conserve water by making informed decisions. Nevertheless, multiple technological and economic barriers could slow down the adoption of these technologies. This study investigates the barriers to adoption of SIS methods in the U.S. part of Rio Grande basin by getting irrigators' perspective and outlines the factors that influence adoption. Multiple adoption barriers are listed, and the most important ones are lack of access to weather data, uncertainty about future water availability, cost effectiveness of technologies, reliability of weather data, lack of availability of irrigation scheduling tools, and risk of reduced yield. Factors that influence the growers' decision to adopt SIS are also explored, which are quality of land, yield, water use efficiency, and water availability for future generations. Age, education, and years involved in agriculture may also govern the knowledge and adoption of SIS methods. The results of this study provide guidance to policy makers and extension experts to strengthen water conservation efforts in Rio Grande basin and other comparable regions in the world.
Irrigation and Drainage, 2019
Inconsistencies in the statistical data sets of irrigated areas at the national level could have ... more Inconsistencies in the statistical data sets of irrigated areas at the national level could have considerable implications for policies developed for food and water security. Remote sensing can address this issue; however, doubts about its reliability inhibit its protagonist role. Methods that integrate both remote sensing based and statistical data sets seem expedient, and they are more likely to be acknowledged by policymakers. Therefore, it is important for scientists to know the basis and limitations of statistical data sets which originate at the country level. Data collection methodologies of irrigated areas have been reviewed for seven Asian countries, namely China, India, Pakistan, Bangladesh, Nepal, Indonesia and Thailand. Factors causing the uncertainties in data, and the limitations of data collection methodologies, were highlighted. Also, an irrigation density distribution analysis was conducted to understand the relation of spatial spread pattern of irrigated areas and uncertainty in their statistical records. It was found that irrigated area statistics are mostly based on information originating from water user associations and farmers, which is either self‐reported or collected through interviews during surveys and censuses. The main causes of discrepancy were lack of resources to frequently enumerate the irrigated land, inconsistency in data collection methodologies, unaccounted secondary crops, illegal and unregulated water use, and bureaucratic and political constraints. Irrigation density distribution analysis showed that largely scattered irrigated areas might be prone to a lack of comprehensive and frequent enumeration. Furthermore, dense irrigation regions might have potentially unrecorded irrigated areas where temporary or supplementary irrigation arrangements are made by marginal farmers.
Water, 2019
A new agricultural drought index was developed for monitoring drought impacts on agriculture in O... more A new agricultural drought index was developed for monitoring drought impacts on agriculture in Oklahoma. This new index, called the Soil Moisture Evapotranspiration Index (SMEI), estimates the departure of aggregated root zone moisture from reference evapotranspiration. The SMEI was estimated at five locations across Oklahoma representing different climates. The results showed good agreement with existing soil moisture-based (SM) and meteorological drought indices. In addition, the SMEI had improved performance compared to other indices in capturing the effects of temporal and spatial variations in drought. The relationship with crop production is a key characteristic of any agricultural drought index. The correlations between winter wheat production and studied drought indices estimated during the growing period were investigated. The correlation coefficients were largest for SMEI (r > 0.9) during the critical crop growth stages when compared to other drought indices, and r decreased by moving from semi-arid to more humid regions across Oklahoma. Overall, the results suggest that the SMEI can be used effectively for monitoring the effects of drought on agriculture in Oklahoma.
2nd World Irrigation Forum (WIF2) Chiang Mai, Thailand, 2016
Asia holds 70% of global irrigated areas and accounts for 62% of world food demand. Existing data... more Asia holds 70% of global irrigated areas and accounts for 62% of world food demand. Existing datasets for irrigated areas, collected by national and international agencies often vary from each other. In this study, a detailed comparison is made within national and global statistics including global irrigated area maps (up to 250m).Variations in data was scaled using statistical tools for national datasets and satellite based estimates. Results of the study show that there is a high variation between satellite based estimates and national statistics for several countries, e.g. India (129%), China (119%), Nepal (103%), Thailand (124%), Indonesia (64%), Vietnam (86%) and Japan (88%). Analysis of the reporting mechanisms of countries under study show that they mostly rely on traditional statistical methods to collect data, e.g. sample or complete surveys based on interviewing farmers, with limited field verification. We used a scoring system to quantitatively scale the reliability of the processes in order to investigate the inconsistency in reported numbers. Moreover, spatial dispersion analysis showed the difference of area estimates for small and large irrigation schemes as 27% and 144% higher than the national statistics respectively for Asia as a whole. The implications of uncertainty came up with some critical questions, i.e. how much is the actual annual land productivity? What is the actually utilized irrigation potential and how far is that from national target? Consequently this study puts forward some critical recommendations to improve the existing reporting systems for irrigated areas information and to look for linking satellite data with the ground truth.
Oklahoma Cooperative Extension Fact Sheets, 2017
Drought could be defined as abnormally dry periods (below-average precipitation) at a given regio... more Drought could be defined as abnormally dry periods (below-average precipitation) at a given region, leading to a shortage of soil moisture and eventually water resources scarcity. It should not be confused with low rainfall conditions that are normal to areas with arid and semiarid climates. During drought, precipitation amounts fall significantly short of long-term averages, posing adverse effects on the environment, including plants and animals, depending on their sensitivity to duration and severity of water stress. If droughts persist for longer periods, they can disrupt local to regional hydrologic cycles, agriculture productivity, ecosystem services and the overall economy.
Oklahoma Cooperative Extension Fact Sheets, 2018
Key Points
• How to interpret soil moisture data regarding water availability in the root zone.
•... more Key Points
• How to interpret soil moisture data regarding water availability in the root zone.
• What Mesonet fractional water index can tell you about soil water content.
• How plant available water indicates water depletion in the root zone.
Teaching Documents by Ali Ajaz
Technical Report, 2014
Since HEISs are relatively a new intervention in South Asia, there exists a dearth of relevant pr... more Since HEISs are relatively a new intervention in South Asia, there exists a dearth of relevant printed material regarding various operational aspects of the systems especially in relation to preparation of fertigation, irrigation and chemigation schedules. Perhaps, the most critical and the most wanted facet of these newly introduced systems is the preparation of proper irrigation schedules for various crops being grown in their command. In addition, the training of project staff and the users of the systems regarding these schedules covering their understanding and implementation in the field appears to be a missing link. A fair analysis of the factors leading to such gaps reflects that lack of technical material on the subject is the primary reason.
The effort made by PSC in the form of this manual is expected to serve the purpose in question. Solved examples of preparation of schedules for a number of crops have been added to give an in depth orientation to the reader. Through requisite review of this manual, it will not only be possible to check and monitor the irrigation schedules supplied on some of the sites by the SSCs for their authenticity and accuracy but it will also enable the project staff especial ly the HEIS teams to prepare and provide the same at the farms/sites without these schedules on instant basis.
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Papers by Ali Ajaz
• How to interpret soil moisture data regarding water availability in the root zone.
• What Mesonet fractional water index can tell you about soil water content.
• How plant available water indicates water depletion in the root zone.
Teaching Documents by Ali Ajaz
The effort made by PSC in the form of this manual is expected to serve the purpose in question. Solved examples of preparation of schedules for a number of crops have been added to give an in depth orientation to the reader. Through requisite review of this manual, it will not only be possible to check and monitor the irrigation schedules supplied on some of the sites by the SSCs for their authenticity and accuracy but it will also enable the project staff especial ly the HEIS teams to prepare and provide the same at the farms/sites without these schedules on instant basis.
• How to interpret soil moisture data regarding water availability in the root zone.
• What Mesonet fractional water index can tell you about soil water content.
• How plant available water indicates water depletion in the root zone.
The effort made by PSC in the form of this manual is expected to serve the purpose in question. Solved examples of preparation of schedules for a number of crops have been added to give an in depth orientation to the reader. Through requisite review of this manual, it will not only be possible to check and monitor the irrigation schedules supplied on some of the sites by the SSCs for their authenticity and accuracy but it will also enable the project staff especial ly the HEIS teams to prepare and provide the same at the farms/sites without these schedules on instant basis.