Planting date plays a significant role in crop production. Early or late planting may decrease grain yield and quality of a crop due to increased biotic (insect, disease, weed), and abiotic (frost, drought, and high temperature) stress. Western North Dakota has a semi-arid climate with annual precipitation of <15 inches (excluding this year's data), which is 5 inches lower than the eastern part of the state. There is a need of determining optimal soybean planting dates and soil temperature for the western part of North Dakota that provide optimum growing period, decrease chances of frost and/or drought damage, and enhance grain yield. We are proposing to repeat an experiment conducted in 2019-20. The outcomes of this research will validate our previous years' findings. The research results will be communicated to clienteles through presentations at field days, workshops, and publications in electronic and printed formats. This project will enable us to provide pertinent information to producers of semi-arid western ND on a suitable soybean planting date and soil temperature that increase soybean yield, quality, and secure a profitable future.

a. To find out an optimal soybean planting date for western ND.
b. To determine an optimal soil temperature (at 4" depth) for planting soybean at western ND.

1. A technical report on the outcomes of the project.
2. An Executive summary of the project.

Updated November 29, 2021:

View uploaded report

Updated August 19, 2022:

View uploaded report

View uploaded report 2

Determining suitable planting date and soil temperature for enhanced growth and yield of soybean under no-till semi-arid condition
(Executive summary – 2021/22)
Principal Investigator: Dr. Gautam Pradhan, NDSU Williston Research Extension Center
Co-Investigators: Dr. Jerald W. Bergman and Dr. James W. Staricka, NDSU WREC

Research Conducted
Two glyphosate tolerant varieties (‘ND17009GT’ and ‘ND18008GT’), either treated with fungicide Obvious @ 4.6 oz/100 lb seed or untreated, were planted on seven different dates (3rd, 10th, 17th, 25th, and 31st of May, and 7th and 14th of June 2021) under no-till dryland conditions.

Why the research is important to ND soybean farmers
Soybean acreage has been steadily increasing in ND, including the western part of the state, which has an exceptionally drier climate (ppt: <15 in/year) than the eastern part (ppt: >20 in/year). There is a lack of soybean production management guidelines suitable for no-till dryland producers of western ND. Determining suitable planting dates and soil temperature is crucial to avoid abiotic and biotic stress and to have a sustainable higher soybean yield and farm income under no-till dryland conditions.

Final findings of the research
2021 was an extreme drought year. From 2020/10/01 to 2021/09/30, we received 9.5 inches of annual precipitation, which was 4.5 inches lower than the 65-year average. The month of June 2022 accounted for ~40% of the 9.5 inches of precipitation.
The effect of seed treatment was not evident on soybean. Soybean planted on June 14th had at least 1.3 times higher plant stand and 1.1 times above ground biomass than other planting dates (Fig. 1A, 1B). Soybean planted on June 14th had 0.9 lb/bu more test weight than the May 17th planting and 1.3 to 1.9 lb/bu higher than all other planting dates (Fig. 1C). Soybean planted on June 14th yielded 16 bu/ac grains, three bushels more than the May 17th planting and six to seven bushels higher than all other planting dates (Fig. 1D). Variety ND17009GT had per acre 5300 more plants, 1.9 lb/bushel more test weight, and 1.8 more bushels grain yield than ND18008GT (Fig. 2A, 2C, 2D).


Benefits/Recommendations to North Dakota soybean farmers and industry
The results from this year showed that a season-long drought might result in a massive decline in soybean yield (avg trial yield: 10.9 bu/ac in 2021 vs. 30 bu/ac in 2019). The relatively higher per acre plant stand and yield from the June 14th planting (16 bu/ac vs. 9-13 bu/ac) indicated that a good rainfall at an appropriate time may make a big difference in the performance of soybean. The results also showed that the variety ND17009GT performs better under severely dry conditions than ND18008GT for plant stand, grain yield, and test weight.

The information on optimal planting dates and soil temperature from this research will ensure sustainable higher soybean yield under semi-arid no-till conditions and thus secure a more profitable future for western ND soy producers.