In irrigated agriculture, the amount and the timing of irrigation play a crucial role in obtaining a sustainable higher yield with minimum adverse effects on the environment. Insufficient irrigation on critical growth stages results in lesser crop yield than the genetic potentiality of a given variety; and excess irrigation leads to higher pumping cost, quick depletion of water resources, leaching of nutrients, and environmental pollution. Soybean is the second largest irrigated crop in ND, however, there is a lack of information on the optimum amount and timing of irrigation of this crop for western ND. In this project, irrigation treatments (amount x timing i.e. growth stage) will be applied using an automated linear system capable of variable rate application. The amount of water to be applied, as per treatments, will be determined based on available soil moisture, precipitation forecasts, current rainfall, soil infiltration rate, and crop growth stages. The research results will be communicated to clienteles through presentations at field days, workshops, and publications. The outcomes of this study will help soybean producers of ND, especially that of western ND, to determine irrigation schedules that enhance yield, water productivity, and soil health; thus, an increased sustainable high farm profit.

1. The main objective of this project is to determine the optimum amount and timing of irrigation for enhanced soybean yield, quality, and water productivity.

2. The secondary objectives are to assess the effect of irrigation treatments

(a) on soil health manifested by changes in soil physical and chemical properties, and

(b) on the manifestation of soybean diseases including but not limited to white mold

1. A technical report on the outcomes of the project.

2. An executive summary of the project.

Update:

Miki Miheguli:
This trial is terminated on Aug 14 with Miki Miheguli's approval. The trail at Williston Research Center received serious hail damage on Monday, August 1, 2023, around 6 pm and wiped-out soybean irrigation plots.

Considering the situation, I approved the project termination request on Aug 13. The NDSC will cover the cost of this trail that occurred until Aug 1. The PI can provide the report with data collected from the trial until the damage occurred. It is impossible to take the yield data from this trial due to devastating hail damage. The trail hail damage photo is saved on Soybean Research database.

The email exchage was saved on Research project change request folder on Email.




Here is the email I received from the PI

"Dear Miki,

I hope this email finds you in good health. As I indicated during our participation in the NDSC Research Priorities Round Table Discussion on July 3rd, 2023, I am writing to offer an update on the present status of the Soybean irrigation project titled "Determination of optimum irrigation amount and timing for enhanced soybean yield, quality, water productivity, and soil health under semiarid western ND."

Unfortunately, I must share that the trial has suffered complete devastation due to a severe hailstorm on Monday, August 1, 2023, around 6 pm. The attached image vividly depicts the extent of the damage, leaving the crop in ruins and regrettably nullifying any prospects of obtaining harvest data for this particular year. I am going to clean the field in the coming days.

I intend to incorporate the soil moisture, growth, and crop health data gathered up until August 1, 2023, into my forthcoming reports. If you have any recommendations or insights regarding this situation, kindly let me know.

Best regards,

Gautam"

Here is my email reply:

Hi Gautam

Thanks for the update. The hail damage to research plot is unfortunate, but unavoidable. I will document this and give you approval to terminate this trial. Please send us invoice that occurred until Aug 1, and keep good record of the event. In your reports, you can provide data and summary until Aug 1. The report is going to miss the yield data but that is ok.

Thank you!

View uploaded report

Updated July 2, 2024:
Determination of Optimum Irrigation Amount and Timing for Enhanced Soybean Yield, Quality, Water Productivity, and Soil Health 2024
(A Technical Report)
PI: Gautam Pradhan, NDSU Williston Research Extension Center
Co-PI: Tyler Tjelde, and James Staricka, NDSU WREC

Research Overview and Objectives

Background
In irrigated agriculture, the amount and timing of irrigation play a crucial role in obtaining a sustainable higher yield with a minimum adverse effect on the environment. Insufficient irrigation results in lesser crop yield than the genetic potentiality of a given variety, while excessive irrigation escalates pumping costs, hastens the depletion of water resources, induces nutrient leaching, and contributes to environmental pollution. Soybean is the second largest irrigated crop in ND preceded by corn. There is a lack of information on the timing and amount of irrigation needed for soybeans under the semiarid conditions of Western ND.

Objectives of the research project
The overall goal of this project is to determine the optimum amount and timing of irrigation for enhanced soybean yield, quality, and water productivity. The secondary objectives are to assess the effect of irrigation treatments on soil health manifested by changes in soil physical and chemical properties, and on the manifestation of soybean diseases including but not limited to white mold.

Materials and Methods
A glyphosate-tolerant soybean variety ND 17009GT was seeded at the Nesson Valley Irrigation Site, Ray, ND (Longitude: -103.1061564, Latitude: 48.1634933) on May 24, 2023, under randomized complete block design with four replications. The seeding rate was 195,000 PLS/ac with row to row distance of 30 in and a gross plot size of 59’ X 50’.
There were 12 irrigation treatments:
1. Full irrigation (I)
2. Deficit irrigation during vegetative stage [(VE – V(n)]
3. Deficit irrigation during flowering stage [R1-R2]
4. Deficit irrigation during pod development stage [R3-R4]
5. Deficit irrigation during seed filling stage [R5-R6]
6. Deficit irrigation during maturity stage [R7-R8]
7. Deficit Irrigation during vegetative + flowering stages
8. Deficit irrigation during vegetative + pod development stages
9. Deficit irrigation during vegetative + seed filling stages
10. Deficit irrigation during vegetative + maturity stages
11. Deficit irrigation during seed filling + maturity stages, and
12. Rainfed (R)
Soil water contents at six different depths (from 6” to 36”) were recorded using a neutron probe. Unmanned aircraft systems equipped with multispectral, thermal, or RGB cameras were flown over the experimental field at different dates to assess canopy temperature (CT), normalized difference vegetation index (NDVI), and normalized difference Red Edge (NDRE).

Research Results/Outcomes
The aerial imagery captured on July 25, 2023, highlighted discernible differences in soybean growth across various treatments. Figure 1 presents representative aerial images depicting four distinct irrigation regimes. Notably, optimal growth was observed under full irrigation (Fig. 1a), with a slight decrease noted under deficit irrigation during the flowering stage (Fig. 1c). Growth was significantly impeded under deficit irrigation during the vegetative stage (Fig 1d), and soybeans subjected to rainfed conditions (Fig. 1b) exhibited a detrimental impact on growth. Figure 2 illustrates the soybean crop as of August 2, 2023, following its complete destruction by a hailstorm on the evening of August 1, 2023.

Figure 1. Aerial image depicting soybean growth under different irrigation regimes. (Aerial imagery captured on July 25, 2023, by Gautam Pradhan): a) Full irrigation; b) Rainfed; c) Deficit irrigation during flowering stage, and d) Deficit irrigation during vegetative stage.

Figure 2. Devastating effect of hailstorm on soybean that occurred on August 1, 2023. (Aerial imagery captured on August 2, 2023, by Gautam Pradhan).


Discussion and Conclusion
The differential impacts of irrigation treatments on soybean growth were evident. However, assessing their impact on grain yield and quality was impeded by hailstorm damage.

View uploaded report

View uploaded report 2

Determination of Optimum Irrigation Amount and Timing for Enhanced Soybean Yield, Quality, Water Productivity, and Soil Health 2024
(Executive Summary)
PI: Gautam Pradhan, NDSU Williston Research Extension Center
Co-PI: Tyler Tjelde, and James Staricka, NDSU WREC

Why the research is important to ND soybean farmers
The research envisages determining the optimum amount and timing of irrigation for soybeans under semiarid conditions. The insights obtained from this research regarding appropriate irrigation amounts and timing will assist soybean producers in western North Dakota in applying the precise amount of water at the right moment. The ultimate advantages will include improved yield, quality, water productivity, and soil health, as well as reduced leaching, environmental pollution, and disease occurrence, leading to increased farm profits.

Research Conducted
Materials and Methods
A glyphosate-tolerant soybean variety ND 17009GT was seeded at the Nesson Valley Irrigation Site, Ray, ND (Longitude: -103.1061564, Latitude: 48.1634933) on May 24, 2023. The seeding rate was 195,000 PLS/ac with Row to Row distance of 30 in and a gross plot size of 59’ X 50’. There were 12 irrigation treatments: (i) Full irrigation, (ii) Deficit irrigation during vegetative stage [(VE – V(n)], (iii) Deficit irrigation during flowering stage [R1-R2] stage, (iv) Deficit irrigation during pod development stage [R3-R4], (v) Deficit irrigation during seed filling stage [R5-R6], (vi) Deficit irrigation during maturity stage [R7-R8], (vii) Deficit Irrigation during vegetative + flowering stages, (viii) Deficit irrigation during vegetative + pod development stages, (ix) Deficit irrigation during vegetative + seed filling stages, (x) Deficit irrigation during vegetative + maturity stages, (xi) Deficit irrigation during seed filling + maturity stages, and (xii) Rainfed (R)

Findings of the research
The aerial imagery captured on July 25, 2023, highlighted discernible differences in soybean growth across various treatments. Notably, optimal growth was observed under full irrigation (Fig. 1a), with a slight decrease noted under deficit irrigation during the flowering stage (Fig. 1c). Growth was significantly impeded under deficit irrigation during the vegetative stage (Fig 1d), and soybeans subjected to rainfed conditions (Fig. 1b) exhibited a detrimental impact on growth. The anticipation to observe the influence of these growth patterns and treatment effects on grain yield and quality was unfortunately disrupted by a hailstorm that occurred on the evening of August 1, 2023, which completely destroyed the entire crop (Fig 2).

Benefits/Recommendations to North Dakota soybean farmers and industry
The hailstorm damage of the entire trial prevented us from noting any project benefits and recommending irrigation technology to North Dakota soybean farmers and industry.

Caption for figures
Figure 1. Representative aerial images depicting soybean growth under different irrigation regimes. (Aerial imagery captured on July 25, 2023, by Gautam Pradhan): a) Full irrigation; b) Rainfed; c) Deficit irrigation during flowering stage, and d) Deficit irrigation during vegetative stage.

Figure 2. Devastating effect of hailstorm on soybean that occurred on August 1, 2023. (Aerial imagery captured on August 2, 2023, by Gautam Pradhan).

According to USDA FSA Crop Acreage Data of 2020, there were about 276,982 acres of irrigated cropland in North Dakota, and soybean was the second largest irrigated crop (63,686 acres) preceded by corn (87,124 acres) and followed by beans (27,366 acres) (USDA-FSA, 2020). According to USDA's 2013 Farm and Ranch Irrigation Survey (USDA-ERS, 2020), about 82 percent of irrigated farms in North Dakota are using “condition of a crop by observation” followed by 56 percent using the “feel of the soil” as means of deciding when to apply water. One of the reasons for these practices is the lack of information on appropriate timing and amount of irrigation for a given crop, including soybean. Information on the appropriate amount and timing of irrigation from this research will help western ND soy producers to apply the judicial amount of irrigation at the proper time. The ultimate benefits will be an enhanced yield, quality, water productivity, and soil health, and decreased leaching, environmental pollution, disease incidence; thus, a higher farm profit.