Diaa Eldin Elshikha

Interests

Research

My research interests are crop water management, micro-irrigation, irrigation system design, deficit irrigation, and precision agriculture. My research goals are focused on optimization of irrigation systems, improving water application for maximum water use efficiency, irrigation scheduling techniques and models, adoption of low water use crops, and detection of crop water status through remote sensing and in-situ soil sensors.

Courses

No activities entered.

Scholarly Contributions

Journals/Publications

• Chen, Y., Dierig, D., Wang, G., Elshikha, D., Ray, D., Maier, R., Neilson, J., & Barberán, A. (2024). Identifying critical microbes in guayule-microbe and microbe-microbe associations. Plant and Soil, 494(1-2), 269-284. doi:10.1007/s11104-023-06269-z
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  Background: Plant-microbe associations play central roles in ecosystem functioning, with some critical microbes significantly influencing the growth and health of plants. Additionally, some microbes are highly associated with other microbes in either competitive or cooperative microbe-microbe associations. Here, we aimed to determine whether there is overlap between critical microbes in plant-microbe and microbe-microbe associations by using guayule (a rubber-producing crop) as a model plant. Methods: Using marker gene amplicon sequencing, we characterized the bacterial/archaeal and fungal communities in soil samples collected from a guayule agroecosystem at six time points that represent changes in guayule productivity and growth stage. The critical microbes in guayule-microbe associations were phylotypes whose relative abundances were positively (positive taxa) or negatively (negative taxa) associated with guayule productivity. Network analysis was used to identify the critical microbes in microbe-microbe associations. Results: Some positive taxa in guayule-microbe associations were ammonia-oxidizing archaea (AOA) and bacteria (AOB) and arbuscular mycorrhizal fungi (AMF), and negative taxa included some microbes resistant to aridity. Some of the critical microbes in microbe-microbe associations were fungal plant pathogens. There were 9 phylotypes representing the overlap between critical microbes in guayule-microbe and microbe-microbe associations. This overlap group included AOB, phototrophic bacteria, AMF, and saprotrophic fungi, along with unique taxa of unknown function. Conclusions: Our study highlighted the association of the soil microbiome with the growth and health of guayule. Our systematic approach narrowed down the immense number of microbial taxa to a ‘most wanted’ list that we define as critical to the entire guayule agroecosystem.
• Chen, Y., Dierig, D. A., Wang, G., Elshikha, D. M., Ray, D. T., Barberán, A., Maier, R. M., & Neilson, J. W. (2023). Identifying critical microbes in guayule‑microbe and microbe‑microbe associations. Plant and Soil. doi:https://doi.org/10.1007/s11104-023-06269-z
• Elshikha, D. M., Waller, P. M., Hunsaker, D. J., Thorp, K. R., Wang, G., Dierig, D., Cruz, V. M., Attalah, S., Katterman, M. E., Williams, C., Ray, D. T., Norton, R., Orr, E., Wall, G. W., & Ogden, K. L. (2023). Water Use, Growth, and Yield of Ratooned Guayule under Subsurface Drip and Furrow Irrigation in the US Southwest Desert. . Water, 15 (19). doi:https://doi.org/10.3390/w15193412
• Elshikha, D. M., Wang, G., Waller, P. M., Hunsaker, D. J., Dierig, D., Thorp, K. R., Thompson, A. L., Katterman, M. E., Herritt, M. T., Bautista, E., Ray, D. T., & Wall, G. W. (2023). Guayule growth and yield responses to deficit irrigation strategies in the U.S. desert. Agricultural Water Management, 277, 108093.
• Katterman, M. E., Waller, P. M., Elshikha, D. M., Wall, G. W., Hunsaker, D. J., Loeffler, R. S., & Ogden, K. L. (2023). WINDS Model Simulation of Guayule Irrigation. Water, 15 (19), 3500. doi:https://doi.org/10.3390/w15193500
• Maqsood, H., Hunsaker, D. J., Waller, P., Thorp, K. R., French, A., Elshikha, D. M., & Loeffler, R. S. (2023). WINDS Model Demonstration with Field Data from a Furrow-Irrigated Cotton Experiment. Water, 15 (8), 1544. doi:https://doi.org/10.3390/w15081544
• Orr, E., Masson, R., Sanyal, D., & Elshikha, D. M. (2023). Surviving these drying times: The role of a desert agricultural extension agent in helping farmers face drought. . JOURNAL OF THE NACAA, 16 (2).
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  A publication to describe the role of a desert agricultural extension agent in helping farmers face drought
• Wang, G., Elshikha, D. E., Katterman, M. E., Sullivan, T., Dittmar, S. H., Cruz, V. M., Hunsaker, D. J., Waller, P., Ray, D. T., & Dierig, D. A. (2022). Irrigation effects on seasonal growth and rubber production of direct-seeded guayule. Industrial Crops and Products. doi:10.1016/j.indcrop.2021.114442
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  Understanding guayule’s response to environmental factors, such as location, soil type, drought stress, and seasonal growth variation is critical for irrigation management to maximize and estimate rubber and resin accumulation throughout the growing seasons. A study was conducted at two sites with different soil types (sandy loam soil at Maricopa, AZ and a clay soil at Eloy, AZ) to compare plant growth and rubber accumulation among different irrigation treatments during a two-year growing season. The above- and below-ground biomass, biomass growth, rubber/resin content, and rubber/resin accumulation were measured every other month from establishment to final harvest in well-watered treatments, which received 100% replacement of crop evapotranspiration (ETc) and irrigated with subsurface drip and furrow (denoted as D100 and F100, respectively), and compared to reduced irrigation treatments (D50 and F50), which received 50% replacement of ETc. Drip irrigation with high water input (D100) decreased root mass partition, but leaf, stem, and flower partitions were not significantly affected by irrigation treatment. Biomass yield was higher in the well-watered treatments as expected, while rubber and resin content were lower, indicating rubber and resin dilution by higher biomass. For all treatments, rubber and resin yield increased linearly over the two-year growing season. However, the rates of increase were different among the irrigation treatments. The D100 treatment had a higher rubber yield increase rate compared to F100 and D50 in sandy loam soil at Maricopa, while the D100 treatment had the lowest increase rate compared to the F100, F50, and D50 treatments in clay soil at Eloy. Top branches of guayule plants in the D100 treatment at Eloy lodged in the second year and likely contributed to lower rubber content and rubber yield in the treatment. The drip irrigation treatments D50 and D100 had higher water productivity for rubber yield at Maricopa. However, the D50 and F50 treatment had the highest water productivity for guayule rubber yield, while the D100 treatment had the lowest due to lower rubber content at Eloy. Root rubber content was 31–39% lower than stem at the two locations. This study indicates that rubber biosynthesis occurred in guayule year-round and that it is possible in clay soils to reduce irrigation without a significant loss in rubber yield.
• Wang, G., Elshikha, D., Katterman, M., Sullivan, T., Dittmar, S., Cruz, V., Hunsaker, D., Waller, P., Ray, D., & Dierig, D. (2022). Irrigation effects on seasonal growth and rubber production of direct-seeded guayule. Industrial Crops and Products, 177. doi:10.1016/j.indcrop.2021.114442
  More info

  Understanding guayule's response to environmental factors, such as location, soil type, drought stress, and seasonal growth variation is critical for irrigation management to maximize and estimate rubber and resin accumulation throughout the growing seasons. A study was conducted at two sites with different soil types (sandy loam soil at Maricopa, AZ and a clay soil at Eloy, AZ) to compare plant growth and rubber accumulation among different irrigation treatments during a two-year growing season. The above- and below-ground biomass, biomass growth, rubber/resin content, and rubber/resin accumulation were measured every other month from establishment to final harvest in well-watered treatments, which received 100% replacement of crop evapotranspiration (ETc) and irrigated with subsurface drip and furrow (denoted as D100 and F100, respectively), and compared to reduced irrigation treatments (D50 and F50), which received 50% replacement of ETc. Drip irrigation with high water input (D100) decreased root mass partition, but leaf, stem, and flower partitions were not significantly affected by irrigation treatment. Biomass yield was higher in the well-watered treatments as expected, while rubber and resin content were lower, indicating rubber and resin dilution by higher biomass. For all treatments, rubber and resin yield increased linearly over the two-year growing season. However, the rates of increase were different among the irrigation treatments. The D100 treatment had a higher rubber yield increase rate compared to F100 and D50 in sandy loam soil at Maricopa, while the D100 treatment had the lowest increase rate compared to the F100, F50, and D50 treatments in clay soil at Eloy. Top branches of guayule plants in the D100 treatment at Eloy lodged in the second year and likely contributed to lower rubber content and rubber yield in the treatment. The drip irrigation treatments D50 and D100 had higher water productivity for rubber yield at Maricopa. However, the D50 and F50 treatment had the highest water productivity for guayule rubber yield, while the D100 treatment had the lowest due to lower rubber content at Eloy. Root rubber content was 31–39% lower than stem at the two locations. This study indicates that rubber biosynthesis occurred in guayule year-round and that it is possible in clay soils to reduce irrigation without a significant loss in rubber yield.
• Wall, G. W., Bronson, K. F., Katterman, M. E., Thorp, K. R., Cruz, V. M., Wang, G., Dierig, D. A., Hunsaker, D. J., Waller, P., & Elshikha, D. E. (2021). Growth, water use, and crop coefficients of direct-seeded guayule with furrow and subsurface drip irrigation in Arizona. Industrial Crops and Products. doi:10.1016/j.indcrop.2021.113819
• Andrade-Sanchez, P., Pauli, D., French, A. S., Elshikha, D. E., Conley, M. P., Thorp, K. R., & Thompson, A. (2019). Comparing Nadir and Multi-Angle View Sensor Technologies for Measuring in-Field Plant Height of Upland Cotton. Remote Sensing. doi:10.3390/rs11060700
• Hunsaker, D., Elshikha, D., & Bronson, K. (2019). High guayule rubber production with subsurface drip irrigation in the US desert Southwest. Agricultural Water Management, 220, 1-12. doi:10.1016/j.agwat.2019.04.016
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  Guayule is being produced for natural rubber in US desert areas, where irrigation requirements are high. Improved irrigation practices and methods are required to increase guayule yields and reduce its water use. Presently, there is no information available on guayule produced using subsurface drip irrigation (SDI). Therefore, we conducted an SDI guayule field study in 2012–2015 in Maricopa, Arizona, US. The objectives were to evaluate guayule dry biomass (DB), rubber yield (RY), and crop evapotranspiration (ETc) responses to water application level, and to compare these results to previously reported guayule irrigation studies. Guayule seedlings were transplanted in the field in October 2012 at 0.35-m spacing, in 100-m long rows, spaced 1.02 m apart. The field had 15, 8-row wide plots (5 irrigation treatments x 3 replicates). Irrigation treatments were imposed in a randomized complete block design starting in May 2013. Irrigation scheduling was based on the measured soil water depletion percentage (SWDp) of a fully-irrigated treatment, defined as 100% ETc replacement, and maintained at ≈20-35% SWDp. The other treatments received 25%, 50%, 75%, and 125% of irrigation applied to the 100% treatment on each day of irrigation. Destructive samples for dry biomass, rubber, and resin contents were periodically taken from each plot between February and November of each year until the guayule was bulk-harvested in March 2015. Results indicated ETc, DB, and RY increased with total water applied (irrigation + rain), which varied between treatments from 2080 to 4900 mm for the 29-month growing season. Final dry biomass and rubber yields of 61.2 Mg/ha and 3430 kg/ha, respectively, were achieved with the highest irrigation treatment level (125%) and these yields were significantly higher than those under all other irrigation levels. All SDI irrigation treatments except for the lowest 25% level had rubber yields from 24 to 200% greater than the maximum RY achieved under a companion surface irrigation study conducted simultaneously in Maricopa.
• Pauli, D., Hunsaker, D. J., Elshikha, D. E., Pugh, N. A., Ilut, D. C., McMahan, C. M., Ponciano, G., & Nelson, A. D. (2019). Transcriptomic and evolutionary analysis of the mechanisms by which P. argentatum, a rubber producing perennial, responds to drought. BMC Plant Biology. doi:10.1186/s12870-019-2106-2

Proceedings Publications

• Attalah, S., Elsadek, E., Waller, P., Hunsaker, D., Thorp, K., Bautista, E., Williams, C., Wall, G., Orr, E., & Elshikha, D. (2024, July 2024). Evaluating the Performance of OpenET Models for Alfalfa in Arizona. In ASABE Conference.
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  This study was conducted to evaluate six satellite-based ET models (ALEXI/DisALEXI, eeMETRIC, geeSEBAL, PT-JPL, SIMS, and SSEBop) and their Ensemble, derived from the OpenET platform, in estimating the actual evapotranspiration (ET) of alfalfa. Then, identify the best-performing OpenET model for alfalfa irrigation management under arid climate conditions in Arizona, USA. Five statistical metrics, the index of agreement (Dindex), Nash-Sutcliffe efficiency coefficient (NSE), mean bias simulation error (MBE), prediction/simulation error (Pe), and coefficient of determination (R2), were used to evaluate the seven alternative estimates in comparison with measured ET (ETmea) at a field scale with four replicates during the 2023 alfalfa growing season in Buckeye, Arizona. Overall, OpenET models and their Ensemble were linearly correlated to average ETmea with R2 > 0.71. Our findings showed that ALEXI/DisALEXI, geeSEBAL, and PT-JPL had a general tendency to underestimate actual ET with acceptable to poor prediction errors (Pe ≤ -35.18 for PT-JPL). In contrast, eeMETRIC, SIMS, and SSEBop overestimated ETmea with acceptable to poor prediction errors (1.86 ≤ Pe ≤ 28.39). Our results highlighted the limitations of using the PT model in arid to semi-arid areas, even after the PT-JPL aridity correction. The Ensemble approach, which combined all OpenET models, showed a high degree of agreement (0.93 ≤ Dindex ≤ 0.96) with the ETmea of alfalfa during the growing period in 2023. R2 ranged from 0.77 to 0.86, with positive NSE values between 0.67 and 0.82. Moreover, the Ensemble approach had significantly lower prediction errors (-6.92 ≤ Pe ≤ 4.04) when compared with six OpenET models, making it the best to simulate alfalfa’s actual evapotranspiration over the study area. This will contribute to providing farmers and decision-makers with the best satellite-based approach for efficient irrigation management and water use in arid regions.
• Elshikha, D., Attalah, S., Elsadek, E., Waller, P., Thorp, K., Sanyal, D., Bautista, E., Norton, R., Hunsaker, D., Williams, C., Wall, G., Barnes, E., & Orr, E. (2024, July). The Impact of Gravity Drip and Flood Irrigation on Development, Water Productivity, and Fiber Yield of Cotton in Semi-Arid Conditions of Arizona. In Aly.
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  The present study was conducted to examine the effects of two irrigation methods with different application rates on cotton (ST 4595B3XF variety) growth, irrigation water productivity, and fiber yield in Arizona. Five treatments, namely gravity drip (GD) with 100%, 80%, and 60% of crop evapotranspiration (ETc) and flood (F) with 100% and 80% of ETc (GD 100%, GD 80%, GD 60%, F100%, and F80%, respectively), were arranged in a randomized complete block design (RCBD) with three replicates during 2023. Deficit irrigation (DI) reduced cotton height and canopy cover with both GD and F irrigations. Compared with the F system, the enhanced vegetative growth resulted in a notable increase in total irrigation requirements, particularly evident in the GD 100% (1337.50 mm) and GD 80% (1106.60 mm). The highest fiber yield values of 1621 kg ha−1 and 1465 kg ha−1 were recorded under an irrigation rate of 100% ETc for both GD and F irrigation. However, decreasing irrigation rates to 80% and 60% ETc negatively affected fiber yield under the two irrigation systems. Improvement of irrigation water productivity (WPI), accompanied by saving irrigation water and a high fiber yield, could be obtained by shifting irrigation from the GD 100% (I = 1337.50 mm, WPI = 0.121 kg m−3) and F100% rates (I = 1162.00 mm, WPI = 0.125 kg m−3) toward the GD 80% rate (I =1106.60 mm, WPI = 0.130 kg m−3). The lowest micronaire (MIC) values were recorded under F 80 % and F 100% (4.36 and 4.97, respectively). The 100% treatment of F and GD showed higher fiber strength (STR) (29.51 and 28.29 HVI g tex−1, respectively). However, the upper half mean length (UHML), uniformity index (UI), and short fiber content (SFC) values showed a downward trend under both GD and F treatments, reflecting their correlation with the total applied water. Elongation at failure (ELO) was consistent among irrigation treatments. This study provides significant guidance for adopting DI strategies in cotton under semi-arid conditions.
• Elshikha, D. E., Attalah, S., Waller, P., Hunsaker, D. J., Thorp, K. R., Williams, C., Katterman, M., Sanyal, D., Wang, G., Dierig, D., & Ray, D. (2023).

  Guayule Germination and Growth under Subsurface Gravity Drip and Furrow Irrigation in Arizona

  . In ASABE.
• Elshikha, D. E., Elshikha, D. E., Attalah, S., Attalah, S., Waller, P., Waller, P., Hunsaker, D. J., Hunsaker, D. J., Thorp, K. R., Thorp, K. R., Williams, C. F., Williams, C. F., Katterman, M. E., Katterman, M. E., Sanyal, D., Sanyal, D., Wang, G., Wang, G., Dierig, D. A., , Dierig, D. A., et al. (2023, July 2023). Guayule Germination and Growth under Subsurface Gravity Drip and Furrow Irrigation in Arizona. In ASABE Conference.
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  Guayule (Parthenium argentatum, A. Gray) is a perennial shrub, native to the desert of northcentral Mexico and southwestern Texas, which produces high quality natural rubber. The annual water requirement under flood irrigation is approximately 732 mm (2.4 acre-ft/year), which is within the annual water allocation depth for many central Arizona farmers. However, under the uncertainty of water supply in some areas, growers might be forced to cut irrigations or adjust their cropping practices. When flood irrigation is used, guayule germination requires about 380 mm of water, which can be reduced when a more efficient irrigation system is adopted. The objective of this study was to compare guayule germination and growth, as well as yield and water productivity under furrow irrigation (FI) and subsurface gravity drip (SGD) irrigation. A direct field-seeded guayule irrigation study was initiated in May 2022 on a 1.5-ha field at the University of Arizona, Maricopa Agricultural Center farm, in Maricopa, Arizona. The field study consisted of six plots: three 100 m x 18.3 m plots were under SGD and three 100 m x, respectively) 8.1 m plots were under FI. The experiment included one flood and one SGD treatments (denoted as F2.5 and D2.5, respectively), which were supposed to receive a predetermined irrigation amount (IA) of 762 mm (2.5 acre-ft/year) but they received 803 mm and 713 mm, respectively. Two other SGD treatments were included in the experiment, denoted as D2.0 and D1.5, which received IA of 615 mm (2.0 acre-ft/year) and 517 mm (1.7 acre-ft/year), respectively. Results indicated that SGD reduced water use during germination by 38%, with IA of 223 mm compared to 360 mm applied under FI, while providing a good crop stand with a slight increase in density (10 plants m-2) compared to FI (8 plants m-2). Moreover, SGD improved guayule yield and water productivity with D2.0 treatment being the best in terms of WP-DBY (1.56 kg m-3), followed by D2.5 (1.25 kg m-3), then D1.5 (1.13 kg/m3). There was no difference in WP-RY among SGD treatments (~0,04 kg m-3) nor in WP-ReY between D2.5 and D1.5 (0.09 kg m-3). The average for the three furrow plots was the lowest (WP-DBY = 0.83 kg m-3, WP-RY = 0.02 kg m-3, WP-ReY = 0.06 kg m-3) despite receiving the highest total irrigation amount [TWA] (941 mm). Rubber content (R, %) and resin content (Re, %) were slightly higher for D2.0 and D1.5 which received less water. Overall, using D2.0 treatment with 615 mm IA could save 20% of water while providing 37% more DBY, 21% more RY, and 47% more ReY than FI, which received 941 mm of water (irrigation + precipitation). (Download PDF)    (Export to EndNotes) ShareFacebookXEmail  
• Ray, D. T., Dierig, D., Wang, G., Sanyal, D., Katterman, M. E., Williams, C., Thorp, K. R., Hunsaker, D. J., Waller, P. M., Attalah, S., Elshikha, D. E., Ray, D. T., Dierig, D., Wang, G., Sanyal, D., Katterman, M. E., Williams, C., Thorp, K. R., Hunsaker, D. J., , Waller, P. M., et al. (2023, Spring).

  Guayule germination and growth under subsurface gravity drip and furrow irrigation in Arizona

  . In 2023 ASABE Annual International Meeting, Paper number 2300034, 19.
• Andrade-Sanchez, P., Elshikha, D. E., & Thorp, K. R. (2021). Irrigation Management Outcomes using Increasingly Complex Geospatial Technologies. In 6th Decennial National Irrigation Symposium, 6-8, December 2021, San Diego, California.
• Waller, P., Katterman, M. E., Bronson, K. F., Cruz, M. V., Wang, S., Dierig, D. A., Hunsaker, D. J., & Elshikha, D. E. (2019). Direct seeded guayule grown in Arizona under furrow and subsurface drip irrigation. In ASABE annual international meeting.
• Bronson, K. F., Elshikha, D. E., & Hunsaker, D. F. (2017). Response of guayule biomass and rubber yield to variable water inputs using subsurface drip irrigation. In 2017 ASABE annual international meeting, Spokane, Washington July 16 - July 19, 2017.
• Sanchez, P., Bronson, K. F., Hunsaker, D. J., & Elshikha, D. E. (2016). Using RGB-based vegetation indices for monitoring guayule biomass, moisture content and rubber. In 2016 ASABE annual international meeting.
• Elshikha, D. E., & Hunsaker, D. J. (2014). Yield and water use of guayule grown in Arizona. In 2014 ASABE annual international meeting.

Others

• Elshikha, D. M., Waller, P., Masson, R., & Subramani, J. (2023, March). Guayule Cultivation and Irrigation Methods for the Southwestern United States.
• Elshikha, D. M., Waller, P., Thorp, K., Angadi, S., Grover, K., & Masson, R. (2023, February). Using Drones for Management of Crops.