Objectives:

This research is a continuous project from our field experiments on automatic soil moisture sensor-controlled drip irrigation for mulched tomato and watermelon in 2019-2020 but focuses on the simulation of the soil water dynamics using the Hydrus-2D model. The Hydrus-2D model is a finite element model for simulating the water, heat and solutes in soil. The specific objectives of this proposed research are to: 

1. Simulate the soil water dynamics for four mulches using Hydrus-2D model under the non-irrigation situation using the measured soil moisture and potential data by TDR, TEROS 21, Hydra probe, and watermark sensors at 5, 15, 30 and 45 cm in 2020 and 2021. 
2. Simulate the soil water dynamics for tomato and watermelon for four mulches using Hydrus-2D model under drip irrigation using the field data in 2019 and 2020.  
3. Evaluate and compare the field measured and model simulated soil water dynamic data for tomato and watermelon crops.  
4. Extend the model results for different soils and crops.  

Progress:

An automatic soil moisture potential sensor-controlled drip irrigation was developed to increase the water use efficiency and vegetable productions under different mulches. Two-year field experiment was conducted in Fargo, ND to test the irrigation system under different mulches. During the field experiment, 96 soil water potential sensors and 96 soil temperature sensors were installed in each plot to monitor the soil water potential and soil temperature at 15 and 30 cm depth.

In 2020, a field experiment was conducted to monitor the surface and subsurface dynamics under clear plastic mulch, black plastic mulch and landscape fabric mulch along with the no mulch treatments. To monitor the soil moisture variation under the surface were monitored by installing several soil moisture and soil water potential sensors at 5, 15, 30 and 45 cm depths. Surface dynamics were monitored by measuring air temperature and relative humidity at different heights from the surface, wind speed, surface temperature measurement and net radiation. During this experiment, surface and subsurface dynamics were measured for different mulches i.e., clear plastic mulch, black plastic mulch and landscape fabric mulch along with no mulch treatments. Using all these instruments, surface and subsurface dynamics were measured under different mulches during a rainfall event and sunny days.

WEM-B controller testing for watermelons using drip irrigation under black mulch

A field experiment was conducted to calibrate WEM-B controller for watermelon production in Fargo silty clay soils. From Vaddevolu et al., 2021, drip irrigation under clear plastic mulch created the favorable conditions for the watermelon crop. In this study, WEM-B controller was tested at different thresholds i.e., 5, 7, 8 and 9 along with no irrigation under clear plastic mulch and no mulch treatments. During the field experiment, soil moisture, soil water potential and soil temperature at 15 and 30 cm were monitored using CR1000 datalogger. Also, rainfall, groundwater table data, yield, fruit quality parameters like pH, electrical conductivity, temperature, and brix (%) were measured to determine the best growing conditions for the watermelon crop in Fargo silty clay soils.

Publications/Presentations/ Trainings

Vaddevolu, U.B.P., J. Lester, X. Jia, T.F. Scherer, and C.W. Lee. 2021. Tomato and watermelon production with mulches and automatic drip irrigation in North Dakota. Water 13(14): 1991. https://doi.org/10.3390/w13141991.

Vaddevolu^$, U.B.P., and X. Jia. 2021. Soil moisture sensor-controlled drip irrigation for watermelon production in North Dakota. 2021 South Dakota Student Water Conference, October 19, 2021. [Oral].

Vaddevolu^$, U.B.P., X. Jia, C. Lee., T. F. Scherer, and J. Lester. 2021. Automated drip irrigation for tomato and watermelon production in the Red River Valley. 2020 ASABE International Meeting, July 12-15, 2020. Virtual Meeting. [Oral].

Vaddevolu^$, U.B.P., X. Jia, T. F. Scherer, and C. Lee. 2021. Vegetable production under different mulches using an automatic soil water potential-based drip irrigation system in North Dakota. ASABE Red River Valley section meeting. [Oral].

Scherer^$, T.F., X. Jia^$, C.W. Lee, U.B.P. Vaddevolu., J. Lester, and D. Lin. 2021. Automatic drip irrigation for specialty crops. Master Gardeners lunch meeting. October 20, 2021, Fargo, ND. Virtual Meeting. [Oral invited].

Jia, X., K. Almen^$, U.B.P. Vaddevolu^$., and J. Lester^$. 2021. Water and soil research update. Department of Agricultural and Biosystems Engineering Seminar. February 26, 2021, Fargo, ND. Virtual Meeting. [Oral].

Vaddevolu, U.B.P., J. Lester, T. F. Scherer, C. Lee, and X. Jia. 2020. Automatic sensor-controlled drip irrigation under mulches for tomato and watermelon productions. 2020 ASABE International Meeting, July 12-15, 2020. Omaha, NE. Paper No. 2001035.

Vaddevolu, U.B.P., X. Jia, T. F. Scherer, and C. Lee. 2020. Automatic sensor-controlled drip irrigation under mulches for tomato and watermelon productions. 2020 ASABE International Meeting, July 12-15, 2020. Omaha, NE. Virtual Meeting. Presentation by Vaddevolu

Vaddevolu, U.B.P., and X. Jia. 2020. Two-stage calibrations for massive watermark potential sensors in guiding irrigation scheduling. 2020 ASA-CSSA-SSSA International Annual Meeting, Nov. 9-13, 2020, Phoenix, AZ. Virtual Meeting. Presentation by Vaddevolu.

USDA selected our research among the funded projects and wrote a blog about our research (https://www.usda.gov/media/blog/2020/08/17/specialty-crop-block-grant-program-and-automation-explored)

Completed a short course on HYDRUS software conducted by Dr. Jirka Simunek.

Submitted an abstract to present about research at the 2020 North Dakota Water Quality Monitoring Conference, which was postponed.

Presented the research to growers/farmers/students through field days, outreach, and education programs.