8:00am-8:15am
Changes in Soil Health Indicators and Microbial Communities Following Conversion of an Unmanaged Sandy Soil to Potato Production
Carl Rosen, University of Minnesota

               Potatoes are typically grown on sandy soils supplemented with irrigation in the Upper Midwest U.S. to ensure high tuber yield and quality.  Soil disturbance is necessary for planting and harvesting, and fumigation is often used to control soil-borne diseases.  To evaluate the impact of potato production on soil health variables, pathogen loads, and soil microbial community structure we compared two adjacent potato fields (Old and New) with different histories.  Both fields were on a Mosford-Hubbard loamy sand soil. The Old field had 40+ years of potato history with soil fumigation in the past 10 years, while the New field was converted from trees, shrubs, and grasses in 2017 and was first used for potatoes in 2019.  Soybeans were planted in both fields in 2018. The 'Goldrush' cultivar was grown in both fields in 2019 and 2021. Soil samples were collected at planting and 60 days later each year from 20 square grids in each 5.7-ha field. Soil health indicators including soil carbon fractions, chemical properties, and physical properties, as well as soil Verticillium propagules and root-lesion nematodes were measured. In addition, soil microbial community structure was determined based on bacterial 16S and fungal ITS rRNA sequence data.  While disease pressure was low and yields did not differ between the fields, there were significant differences in soil health indicators and microbial community structure. Soil organic matter in the New field was twice that in the Old field.  The New field had a higher abundance of Candidatus Udaeobacter and a lower abundance of Sporosarcina than the Old field.  More Penicillium and Gibellulopsis were present in the Old field, while more Pseudogymnoascus, Plectosphaerella, and Clonostachys were found in the New field.  These results demonstrate how soil health indicators and microbial community structure can be altered when natural fields are converted to potato production.  

8:15am-8:30am
Effect of Various Cover Crops on Soil Health of Potato Fields
Ruijun Qin, OSU

               Cover crops are often reported to promote soil health and enhance the yield of subsequent crops. However, in the Columbia Basin, the predominant options for cover crops are typically limited to wheat or occasionally mustard, so there is a need to develop more cover crop options for enhancing crop sustainability and soil health. In a field with the Adkins sandy loam soil, we carried out a field trial with 11 treatments, including barley, brassica, clover, kale, pea plus fava mix, rye, ryegrass, triticale, turnip, vetch, and non-cover crop control. The experimental design followed a randomized complete block design with four replicates. The cover crops were sown in October 2021 and terminated in April 2022, after which the fields were transitioned to potato cultivation and harvested in September 2022. Results showed that cover crops reduced sulfur, manganese, and C: N ratios but increased iron levels compared to the control before cover crop termination. Following potato harvest, soil pH, calcium, and C: N ratios decreased, whereas iron, total nitrogen, organic nitrogen, and organic nitrogen release increased in the cover crop treatments compared to the control. There were no differences observed in potato yield, internal defects, or specific gravity between the cover crop treatments and the control. The research findings from this project suggest that incorporating cover crops into potato rotation systems can have a positive impact on soil health parameters without compromising potato yield or quality.

8:30am-8:45am
The effects of disease management strategies on the potato soil microbiome, yield, and Verticillium wilt in West Central MN
Kimberly Zitnick-Anderson, North Dakota State University

               Soil health plays a crucial role in sustainable agriculture, disease suppression, and enhancing crop production. However, the role and importance of soil health indicators, including the soil microbiome, remains limited for potato. The objective of this study was to examine how crop rotation and soil amendments affect the soil microbiome, Verticillium wilt severity, and tuber yield/quality. Research plots were established and fumigated in the fall of 2018 in West Central Minnesota. Six paired treatments of rye cover crops, mustard bio-fumigation, turkey manure amendments, and standard grower treatments were nested within 2- and 3-year potato rotations with field pea, corn, and wheat. The 3-year rotation was planted to potatoes in 2019 and 2022; the 2-year rotation was planted to potatoes in 2020 and 2022. The standard grower treatments were fumigated again prior to planting potatoes in 2022. Soil samples were collected yearly from each plot. 16s and ITS amplicon sequencing was performed on DNA extracted from sampled soil. Plots were visually evaluated for Verticillium wilt development. Tuber yield, grade, and quality attributes were recorded post-harvest. The 3-year potato rotation resulted in higher marketable yield, lower Verticillium wilt, and increased bacterial and fungal α-diversity when compared to the 2-year rotation. Analysis of bacterial and fungal β-diversity indicate microbiome dissimilarities between the 2- and 3-year potato rotations, and across the 4 years the study was conducted. These findings suggest that increasing potato rotations from 2- to 3-years improves overall sustainability of the cropping system. Although differences between potato rotation lengths were observed, the effects of specific treatments on tuber yield and quality, and Verticillium wilt were not detected in this 4-year study.

8:45am-9:00am
Relationships among thermo-stability, potato tuber yield, soil health indicators and nematodes. 
George W. Bird, Michigan State University

               The relationships among thermo-stability, soil health indicators, nematodes and potato tuber yields were evaluated in 2017, 2018 and 2019. Season-long thermo-stability was measured using sensors mounted on a drone flown multiple times throughout the growing seasons, beginning before primary tillage and ending after potato harvest. The data were used to generate maps where zones identified as hot and stable had temperatures consistently 5o C higher than zones described as cold and stable. The thermo-stability maps include four categories: hot and stable, medium, and stable, cold, and stable, and non-stable. Multiple geo-positioned soil samples for soil health and nematode analyses were collected prior to primary tillage.  The samples were evaluated for four physical, four chemical and four biological soil health indicators at the Cornell University Soil Health Laboratory and for nematode community structure at the Michigan State University Plant Diagnostic Laboratory. The pre-plant geo-positioned soil sample locations were used as sites for hand-dug tuber yield estimates.  One circa fifty-acre commercial potato field was evaluated each year.  The 2017 field was in Mecosta County and the 2018-2019 fields in Montcalm County.  Tuber yields in all three years and fields were significantly greater (P=0.05) in cool and stable zones compared to hot and stable zones; 449 cwt per acre versus 340 cwt per acre, respectively.  In general, the physical, chemical, and biological soil health indicators were higher in cool and stable compared to hot and stable zones. Pratylenchus penetrans (penetrans root-lesion nematode) was present in all three fields.  High population densities of a Dorylaimus sp. were associated with hot and stable zones in the Mecosta County field.  

9:00am-9:15am
Effect of the Application of Biochar, Organic Manure, and Inorganic Fertilizers on Potato Productivity and Soil Quality
Tajamul Hussain, Hermiston Agricultural Research and Extension Center, Oregon State University

               Excessive applications of inorganic fertilizers to maximize crop yields often lead to increased nutrient losses resulting in soil and environmental impacts. Biochar and organic manures as soil amendments have potential to improve soil properties and reduce environmental effects. However, the scientific evidence on the application of these amendments in the Columbia Basin of Eastern Oregon is limited. Therefore, two-year field experiments were conducted on the Adkins fine sandy loam soil in Hermiston, Oregon during 2017 and 2018 to evaluate corn and potato yields and soil quality parameters under different applications of biochar, organic manure, and chemical fertilizers. The experiments followed randomized complete block design with four replications and the treatment combinations included, a chemical fertilizer application (NPK), co-application of NPK and woodchip biochar at 50%, 100%, and 200% rate, co-application of NPK and coconut biochar at 100% rate and application of manure at 100% and 50% rate as well as a non-fertilized control treatment. Results from the potato experiments indicated that the application of biochar and manure did not significantly impact on total or marketable yield compared to NPK treatment and total yield for potato ranged 32–37 tons acre-1. Soil properties differed significantly over three soil layers while organic matter, magnesium, ammonium nitrate (NH4+), sulfur, and boron exhibited significant differences among applied treatments. Biochar and manure application positively impacted on soil by reducing nitrate leaching whereas manure amendment showed a positive effect in mitigating soil acidification compared to NPK. Findings of this study provide scientific evidence on the impacts of biochar and manure applications in sandy soil and are useful in adjustment of biochar and manure application rates for future investigations. Future studies should consider long term evaluations for exploring the potential of using biochar and manures in the irrigated fields in the Columbia Basin of Eastern Oregon.

9:15am-9:30am
Liquid Phosphorus Fertilizer Placement Strategies to Improve Phosphorus Availability and Utilization in Potatoes.
Samuel YC Essah, Colorado State University, Department of Horticulture and Landscape Architecture, San Luis Valley Research Center

               "Phosphorus (P) is a poorly soluble plant nutrient. Therefore, P uptake by the potato crop is primarily through root interception and short distance diffusion. This limits the percentage of soil supplying P to potato roots. Placement of P fertilizer is a management variable that can influence P uptake and P use efficiency, thereby improving tuber yield and quality. Recent studies conducted at Colorado State University’s San Luis Valley Research Center, USA, has shown that blending orthophosphate fertilizers with 10-34-0 reduces required P fertilizer cost and improves P use efficiency, as well as increase potato tuber yield and quality, compared to using 10-34-0 as sole source of P fertilizer. Information on placement strategies of blended liquid P fertilizers for maximum use efficiency and tuber performance has not been well documented. Studies were conducted at Colorado State University’s San Luis Valley Research Center, with the objective of evaluating the effect of blended liquid P fertilizer placement strategy on Russet potato performance in the field. Three orthophosphate fertilizers each blended with 10-34-0 were evaluated under three placement methods (banding, in-furrow, and banding + in-furrow application). Banding of blended liquid P fertilizers increased medium size (4-10 oz) tuber yield by 22%, compared to in-furrow application. In-furrow application of blended liquid P fertilizers increased production of premium size (> 6 oz and > 10 oz) tuber yield by 8 and 49%, respectively, compared to banding application.Results from this study suggest that blended liquid P fertilizer placement strategy can enhance sustainable potato production.”

9:30am-9:45am
Effect of Potassium Fertilizer Rate and Source on Irrigated Potatoes
Ruijun Qin,OSU              

               Potassium (K) fertilization is a standard practice among potato growers in the Columbia Basin, where application rates typically range from 100 to 400 lb/ac, in the soils with available K levels of 50 to 300 ppm. However, little information is available on the effect of K fertilizer rate and source on the yield and quality of different potato cultivars currently grown in the region. To address this knowledge gap, trials were conducted over two years in a producer's field near Boardman, Oregon. The study investigated two K fertilizer sources (muriate of potash and sulfate of potash) and five application rates ranging from 0 to 800 lb K2O/ac, across three potato cultivars including Clearwater Russet, Russet Burbank, and Umatilla Russet. Tuber yield and quality were assessed upon harvest. Results showed that the K fertilization significantly increased the tuber yield of >4 oz and >6 oz. Although varied with the years and K sources, the lowest total yields were also shown in the treatment with K application. Higher K rates tended to decrease the tuber-specific gravity, suggesting a potential impact on tuber quality.  The potato yield and quality were not affected by K sources but were highly impacted by the year and cultivars. The research findings provide valuable insights into optimizing K fertilization strategies to enhance potato yield and quality, thus contributing to the sustainable management of potato production in the region.