In a recent article in this space, I provided a summary of some recent work from the Dr. J S. Famiglietti program at Arizona State University (ASU). Dr. Famiglietti is a Global Futures Professor and hydrologist with the School of Sustainability, and he serves as the director for ASU’s Arizona Water Innovation Initiative.
The work I recently summarized was published in the Geophysical Research Letters journal (Abdelmohsen et al., 2025) with the American Geophysical Union (AGU). That article describes the declining groundwater supplies in the lower Colorado River basin (LCRB). The methods for conducting this analysis are described in other publications (Rodell, Famiglietti et al., 2004; Rodell, Houser et al., 2004).
Additional work from the Famiglietti group has recently been published with their findings regarding a global review of terrestrial water storage (TWS) as a critical indicator of freshwater availability. In their methodology, they again used NASA GRACE/GRACE-FO data to show that the continents have undergone unprecedented TWS loss since 2002 (Chandanpukar, et al. 2025).
Some results of this study are summarized in Figures 1 and 2 revealing areas of intense TWS loss in this century. Mexico and Central America, the desert Southwest and other areas in the United States, i.e., California and the Ogallala Aquifer on the high plains, are clearly identified as having severe depletions of TWS, both surface and groundwater. These three regions are collectively identified as one large southwestern North American-Central American mega-drying region.
This work represents one piece of an ensemble of studies conducted by Famiglietti and his colleagues in recent years (Castle, 2014; Chandanpurkar, 2021; Famiglietti, 2014; Famiglietti, 2019; Famiglietti and Ferguson, 2021; Khorrami, 2023; Mohan, 2023; Rodell, 2018; Rodell, Famiglietti, 2004; Rodell, Houser, 2004; Scanlon, 2023;Voss, 2013; and Xu, 2023). Their methods are well-established, and they have been thoroughly scrutinized and reviewed.
Important conclusions from this study show that because of the increasing aridification along with increasing demand among many areas across the entire planet between 2002 to 2024, the availability of surface water and the levels of groundwater storage have substantially decreased.
The depletion of TWS is impacting many regions of the world. These depletions are particularly severe in many arid and semi-arid regions. As surface water sources have declined with increasing aridity in many areas, that has contributed to increasing demand for groundwater resources.
The current water crisis in Iran demonstrates the degree of severity that many parts of the world are experiencing, Kowser and Nader, 2025. The basic needs for Iran in dealing with their water crisis is like many other countries and regions. The key points that need immediate attention include improved and well-integrated agronomic programs (i.e., crop-soil-water management), incentive-based polices, strict legal enforcement, and ongoing evaluation and oversight. Like many regions, including Arizona and the desert SW of the U.S., the Iranians need immediate action, both short and long-term.
Arizona agriculture will be continually forced to deal with the increasing urban population and the diminishing water supplies. The recent results coming from Abdelmohsen et al., (2025) provide a valuable assessment of groundwater supplies in the LCRB and Arizona and the importance of conservation measures. As groundwater supplies are further diminished, that will likely direct more attention surface water sources and intensify the competition for all TWS sources. The recent work from Chandanpukar, et al. (2025) further demonstrates the importance of our water conservation needs.
This also reinforces the critical need for Arizona to develop functional groundwater legislation for areas beyond the established AMAs. It is imperative that we manage the water resources we have with great care and discipline. No one is going to come save us and there are no other water resources we can draw from. We need valid and realistic information to work with (i.e. Chandanpukar et al., 2025) and we need practical and effective conservation guidelines employed.
Fig. 1. Global map of long-term TWS trends from GRACE/FO.
(A) Trends in TWS (cm year−1) from February 2003 to April 2024 (see Materials and Methods). Mega-regions (regions exceeding −0.2 cm year−1 and connecting previously reported TWS hot spots) are outlined in black and labeled 1 to 4 corresponding to the main text. (B) Zonal sum of TWS trends for all (black) and non-glaciated regions (red). Source: Chandanpukar, et al. 2025.
Fig. 2. Mapping robustness of TWS trends.
(A) Drying and wetting land regions from where the TWS trend sign has been persistent and less sensitive to the increasing GRACE/FO record length. (B) Ratio of local interannual variability of detrended TWS anomalies to their long-term local trends. The red and blue color bars indicate regions with decreasing TWS trend and increasing TWS trend from Figure 1. Source: Chandanpukar, et al. 2025.
References
Abdelmohsen, K., Famiglietti, J. S., Ao, Y.Z., Mohajer, B., & Chandanpurkar, H. A. 2025. Declining freshwater availability in the Colorado River basin threatens sustainability of its critical groundwater supplies. Geophysical Research Letters, 52,e2025GL115593. https://doi.org/10. 1029/2025GL115593
Castle, S.L., B.F. Thomas, J. T. Reager, S. C. Swenson, M. Rodell, J. S. Famiglietti. 2014. Groundwater depletion during drought threatens future water security of the Colorado River Basin. Geophys. Res. Lett. 41, 5904–5911.
Chandanpurkar, H.A., J. T. Reager, J. S. Famiglietti, R. S. Nerem, D. P. Chambers, M.-H. Lo,B. D. Hamlington, T. H. Syed. 2021. The seasonality of global land and oceanmass and the changing water cycle. Geophys. Res. Lett.48,e2020GL091248.
Chandanpukar, H.A.,Famiglietti, J.S., Gopalan, K, Wiese, D.N., Wada, Y., Kakinuma, K., Reager,J.T., and Zhang, F. 2025. Science Advances, Vol. 11, Issue 30, 25 July 2025. DOI:10.1126/sciadv.adx0298
Famiglietti, J.S. 2014. The global groundwater crisis. Nat. Clim. Chang. 4,945–948.
Famiglietti, J.S. 2019. A map of the future of water. Trend Magazine, 3 March2019.
Famiglietti, J.S. and G. Ferguson. 2021. The hidden crisis beneath our feet. Science 372,344–345.
Khorrami, M.,M. Sherzaei, K. Ghobadi-Far, S. Werth, G. Carlson, and G. Zhai. 2023. Groundwater volume loss in Mexico City constrained by In SAR and GRACE observations and mechanical models. Geophys. Res. Lett.50,e2022GL101962.
Kowsar, N. and A. Nader. 2025. Iran’s TapsAre Nearly Empty: After five straight years of drought, the country is running dry. Foreign Policy, 7 August 2025.
Mohan, C., T. Gleeson, T. Forstner, J. S. Famiglietti, I. de Graaf. 2023. Quantifying groundwater’s contribution to regional environmental-flows in diverse hydrologic landscapes. Water Resour. Res. 59,e2022WR033153 (2023).
Rodell, M., J. Famiglietti, D. N. Wiese, J.T. Reager, H. K. Beaudoing, F. W. Landerer, M.-H. Lo. 2018. Emerging trends inglobal freshwater availability. Nature 557, 651–659(2018).
Rodell, M., Famiglietti, J.S., Chen, J., Seneviratne, S. I., Viterbo, P., Holl, S., &Wilson, C. R.2004. Basin scale estimates of evapotranspiration using GRACE and otherobservations. Geophysical Research Letters, 31(20), L20504. https://doi.org/10.1029/2004GL020873
Rodell, M., Houser, P. R.,Jambor, U., Gottschalck, J., Mitchell, K., Meng, C.‐J., et al. 2004. The global land data assimilation system. Bulletin America Meteorology Social, 85(March),381–394. https://doi.org/10.1175/BAMS853381
Scanlon, B.R., S. Fakhreddine, A. Rateb, I. deGraaf, J. S. Famiglietti, T. Gleeson, R. Q.Grafton, E. Jobbagy, S. Kebede, S. R. Kolusu, L. F. Konikow, D. Long, M.Mekonnen, H. M. Schmied, A. Mukherjee, A. MacDonald, R. C. Reedy, M.Shamsudduha, C. T. Simmons, A. Sun, R. G. Taylor, K. G. Villhoth, C. J.Vorosmarty, and C. Zheng. 2023. Global water resources and the role of groundwater in a resilient water future. Nat. Rev. Earth Environ. 4,87–101.
Silvertooth,J.C. 2025. Groundwater assessment in the lower Colorado River basin. Universityof Arizona, Vegetable IPM Newsletter, Vol. 16, No. 14.
Voss, K.A., J. S. Famiglietti, M. Lo, C. R. de Linage, M. Rodell, and S.C. Swenson. 2013. Groundwater depletion in the Middle East from GRACE withimplications for transboundary water management in the Tigris-Euphrates-WesternIran region. Water Resour.Res. 49, 904–914.
Xu, L., J. S.Famiglietti. 2023. Global patterns of water-driven human migration. WIREsWater 10, e1647
At events and in the halls of the Yuma Agricultural Center, I’ve been hearing murmurings predicting a wet winter this year…
As the Yuma Sun reported last week, “The storms of Monday, Aug. 25 [2025], were the severest conditions of monsoon season so far this year in Yuma County, bringing record-rainfall, widespread power outages and--in the fields--disruptions in planting schedules.”
While the Climate Prediction Center of the National Weather Service maintains its prediction of below average rainfall this fall and winter as a whole, the NWS is saying this week will bring several chances of scattered storms.
These unusually wet conditions at germination can favor seedling disease development. Please be on the lookout for seedling disease in all crops as we begin the fall planting season. Most often the many fungal and oomycete pathogens that cause seedling disease strike before or soon after seedlings emerge, causing what we call damping-off. These common soilborne diseases can quickly kill germinating seeds and young plants and leave stands looking patchy or empty. Early symptoms include poor germination, water-soaked or severely discolored lesions near the soil line, and sudden seedling collapse followed by desiccation.
It is important to note that oomycete and fungal pathogens typically cannot be controlled by the same fungicidal mode of action. That is why an accurate diagnosis is critical before considering treatments with fungicides. If you suspect you have seedling diseases in your field, please submit samples to the Yuma Plant Health Clinic or schedule a field visit with me.
National Weather Service Climate Prediction Center: https://www.cpc.ncep.noaa.gov/
National Weather Service forecast: https://forecast.weather.govFinger weeders are an in-row weeding tool made from flexible rubber. Pairs are centered on the seed row and overlapped slightly to remove in-row weeds. Our experience has been that finger weeders are effective at removing small weeds (< 3-4 leaf stage), but not large, well anchored weeds. A Texas A&M University colleague shared that they were able to regularly remove 3-4inch tall Palmer Amaranth with finger weeders using a cultivator configuration developed by organic cotton grower Carl Pepper. I was pretty impressed by their video. I think you will be too. Check it out by here or by clicking on the image below.
Acknowledgements
Credit and thanks are extended to Kyle R. Russell, Texas A&M University, for capturing and sharing the video.
Fig. 1. Large Palmer Amaranth being removed from the plant row by finger weeders –
slow motion video. (Video credit: Kyle R. Russel, Texas A&M University. Cultivator
configuration credit: Carl Pepper, Lubbock, TX.)
My name is Mazin Saber, and I serve as an Associate in Extension specializing in Weed Management at the School of Plant Sciences, University of Arizona/Yuma County Cooperative Extension, based at the Yuma Agricultural Center. My work focuses on developing innovative site-specific weed management strategies tailored to specialty crop systems in desert agriculture, aiming to establish effective and sustainable weed control programs. I currently lead a new weed control research initiative at the Yuma Agricultural Center.
My academic background includes a Bachelor’s degree in Agricultural Mechanization and a Master’s degree in Agronomy from the University of Basrah, Iraq. I also hold an M.E., and Ph.D. in Agricultural and Biological Engineering from the University of Florida, where my doctoral research focused on designing automated mechanical intra-row weed control system for row crops.
Previously, my research has involved quantitative assessment of crop water-use and salt balance in the Lower Colorado River region. By utilizing advanced tools such as Eddy Covariance to measure evapotranspiration across 14 major crops over multiple seasons on commercial farming, I have contributed to improving water use efficiency and enhancing the sustainability and competitiveness of desert agriculture.
As I build my weed management program, I am conducting an assessment survey to identify the most pressing weed management challenges. Your feedback is crucial to ensure this program meets your needs. Please take a few minutes to complete the survey using the link below.
https://uarizona.co1.qualtrics.com/jfe/form/SV_4Od09r4hPLThLz8
I am available for any discussions about weed issues on your farm and I am happy to arrange field visits or ride-alongs to better understand your specific challenges. Please feel free to reach out to me directly.
Integrated pest management (IPM) involves the utilization of a combination of several tactics for the effective management of pests. This concept was developed by entomologists and is currently adopted by pest managers to target various pests, including insects, weeds, and pathogens. Most IMP tactics fit well in both conventional and organic crop production. It is not uncommon that most pest management techniques (for organic or conventional production) are not very effective as a stand-alone tactic. Therefore, it is essential to use a combination of tactics that will complement each other to control the pests adequately. This is like a “many little hammers” approach, where each of the management tactics is a little hammer hammering on the pests, resulting in a cumulative suppression.
When developing an IPM program, it is important to prioritize planting resistant or tolerant crop varieties and adopting agricultural practices that promote plant health and resilience. Other practices, including physical, mechanical, or biological control, can be implemented to further reduce the pest populations. It is critical to conduct regular scouting to monitor pest populations and use economic thresholds to guide insecticide application decision-making.
Figure 1. Integrated pest management cycle. 1st:pest identification; 2nd: prevention;
3rd: monitoring; 4th: select options; 5th: control action; 6th: evaluation.
Below are some IPM tactics that can be considered in your organic IPM programs:
Implementing IPM will result in economic benefits while preserving the environment and reducing negative impacts on human health. In other words, IPM aims at managing pests in an economically viable, socially acceptable, and environmentally safe manner. It is important to note that not all the IPM tactics are always viable in all situations, and IPM is not a one-size-fits-all solution.
Therefore, the selection of management techniques for an IPM program should be done on a case-by-case basis.
As we approach the start of the upcoming season, it's a perfect time to revisit irrigation efficiency strategies, a critical component for both conventional and organic cropping systems across Arizona.
Extension professionals in Central Arizona requested a resource to help growers better understand how to manage irrigation more effectively. In response, we developed a short video explaining key strategies for efficient water use, including how to integrate weather station tools into your decision-making process.
This video provides simple, practical guidance on:
Arizona is fortunate to have a robust network of weather stations called Arizona Meteorological Network (https://azmet.arizona.edu/). I highly encourage you to identify the one closest to your location and start leveraging it as part of your irrigation planning and scheduling. These data-driven strategies can help you make more informed, sustainable, and profitable decisions in the field. If you have any questions or need help getting started, please feel free to reach out.
Wishing you a productive and water-wise season for your organic/conventional cropping systems ahead!
Watch the Video: Irrigation Efficiency for Farms (YouTube)
Results of pheromone and sticky trap catches can be viewed here.
Corn earworm: CEW moth counts down in most over the last month, but increased activity in Wellton and Tacna in the past week; above average for this time of season.
Beet armyworm: Moth trap counts increased in most areas, above average for this time of the year.
Cabbage looper: Moths remain in all traps in the past 2 weeks, and average for this time of the season.
Diamondback moth: Adults decreased to all locations but still remain active in Wellton and the N. Yuma Valley. Overall, below average for January.
Whitefly: Adult movement remains low in all areas, consistent with previous years.
Thrips: Thrips adults movement decreased in past 2 weeks, overall activity below average for January.
Aphids: Winged aphids are still actively moving, but lower in most areas. About average for January.
Leafminers: Adult activity down in most locations, below average for this time of season.
