Research & Evidence

The Science Behind the Sensors

Published university and USDA research validating the sensor technology we deploy. These are not our case studies — they are the peer-reviewed science that proves this approach works.

Transparency note: The studies below are published research from universities and government agencies — not TerraVue USA customer installations. We reference this work because TerraVue USA deploys the same sensor technologies (soil moisture, leaf wetness, soil temperature, tile drain monitoring) validated in these studies. All sources are cited. We believe in letting the science speak for itself.

Central Iowa (Story & Boone Counties)2,000 acres studiedCornCorn/Soy Rotation

Sensor-Driven Fungicide Timing Protects Corn Yield During Tar Spot Outbreaks

Iowa State University Extension & Outreach — Integrated Crop ManagementView source

!The Challenge

Tar spot (Phyllachora maydis) has spread rapidly across Iowa since 2018, causing yield losses of 20-60 bushels per acre in severe outbreaks. The challenge for growers is timing: fungicide applications are only effective when applied preventatively before infection establishes, but spraying on a calendar schedule wastes money in low-risk years and may miss the actual infection window. ISU research has shown that tar spot infection requires extended leaf wetness (7+ hours) at temperatures between 60-70°F — conditions that vary field-by-field based on topography, canopy density, and proximity to waterways.

Technology Used in This Research

In-canopy leaf wetness and temperature sensors placed at ear height across corn fields, feeding data to disease risk models based on ISU and Crop Protection Network research. Sensors track the cumulative hours of leaf wetness at temperatures favorable for tar spot spore germination, alerting growers when infection thresholds are reached. This is the same sensor technology TerraVue USA deploys.

Yield Impact

ISU trials documented that properly timed fungicide applications (VT-R2, triggered by disease risk models) protected 20-40 bushels per acre compared to untreated checks in moderate-to-high tar spot pressure years. At $4.50/bu corn, that is $90-$180/acre in protected yield.

Input Savings

Sensor-based timing reduced unnecessary fungicide applications by 1-2 passes in low-pressure years, saving $15-$25/acre per avoided application. In high-pressure years, timely application avoided the $90-$180/acre yield loss that results from spraying too late or not at all.

Operations

Field-level data replaced county-level scouting reports as the basis for spray decisions. Growers could prioritize fields with the highest infection risk rather than spraying all fields on the same schedule. Disease risk alerts provided 24-48 hours of lead time to mobilize application equipment.

→Why This Matters for Your Farm

ISU research confirms that sensor-based disease forecasting enables growers to spray the right fields at the right time — reducing cost in low-pressure years and protecting yield in outbreak years. The technology TerraVue USA deploys uses the same leaf wetness and temperature monitoring approach validated in this research.

Source: Mueller, D. & Robertson, A. — Iowa State University Extension ICM News; Crop Protection Network Publication CPN-2012. Fungicide efficacy trials published through ISU Integrated Crop Management program.

North-Central Iowa (Des Moines Lobe soils)3,000 acres studiedCornCorn/Soy Rotation

Soil Moisture Monitoring Reduces Nitrogen Loss from Saturated Soils by 10-25%

Iowa State University — Iowa Nutrient Reduction Strategy & N Management ResearchView source

!The Challenge

In Iowa's poorly drained Des Moines Lobe soils (Clarion-Nicollet-Webster association), nitrogen loss through denitrification is one of the largest controllable production costs. ISU research documents that saturated soil conditions cause denitrification losses of 2-5 lbs N/acre/day. A single 3-day saturation event can destroy $15-$25/acre worth of applied nitrogen. Without real-time soil moisture data, growers have no way to know which fields are losing nitrogen or when rescue applications are needed.

Technology Used in This Research

Multi-depth soil moisture sensors (8-inch, 16-inch, 32-inch) installed across representative soil zones within each field, with tile drain flow monitors. Sensors detect when root-zone saturation exceeds denitrification thresholds and alert growers within hours — enabling timely rescue nitrogen sidedress decisions. This is the same sensor and monitoring approach TerraVue USA deploys.

Yield Impact

ISU nitrogen management research shows that timely rescue sidedress applications (based on soil conditions rather than calendar) can recover 10-20 bu/acre of yield that would otherwise be lost to nitrogen deficiency. At $4.50/bu, that is $45-$90/acre in protected yield.

Input Savings

Real-time saturation monitoring enables targeted sidedress applications only on fields that actually lost nitrogen, rather than blanket applications across the entire operation. Research documents 10-25% improvement in nitrogen use efficiency, saving $10-$30/acre in avoided over-application on fields that did not need it.

Operations

Late Spring Nitrate Test (LSNT) decisions supported by real-time soil moisture history. Tile drain monitoring provides early warning of nitrogen movement below the root zone. Data supports Iowa Nutrient Reduction Strategy compliance and conservation practice documentation.

→Why This Matters for Your Farm

ISU research confirms that real-time soil moisture monitoring at multiple depths can identify nitrogen loss events as they happen, enabling rescue applications that protect yield while reducing overall nitrogen use. TerraVue USA deploys the same multi-depth sensing technology validated in this research.

Source: Sawyer, J. & Mallarino, A. — ISU Extension PM 2015 (Nitrogen Use in Iowa Corn Production); Iowa Nutrient Reduction Strategy Science Assessment (2013, updated 2017). Denitrification rates: Parkin & Hatfield, USDA-ARS National Laboratory for Agriculture and the Environment, Ames, IA.

Central Iowa (Multiple Counties)2,500 acres studiedCornSoybeans

Field-Level Soil Temperature Monitoring Optimizes Corn Planting Windows Worth $22-$120/Acre

Iowa State University Extension & USDA-NRCS Soil Climate Analysis NetworkView source

!The Challenge

ISU research documents that corn planting date is one of the highest-value management decisions Iowa growers make each year. Planting into soil below 50°F at seed depth risks poor germination, imbibitional chilling injury, and increased vulnerability to seedling diseases. Yet regional soil temperature reports (from county-level SCAN stations) often do not reflect actual conditions in individual fields — south-facing slopes warm days earlier than north-facing slopes, and well-drained knolls are plantable before poorly drained bottoms in the same section.

Technology Used in This Research

Soil temperature sensors at 2-inch and 4-inch depths across representative field positions (hilltop, mid-slope, bottom), paired with soil moisture sensors to assess trafficability. Real-time data streams to a planting-readiness dashboard that shows field-by-field conditions. This is the same sensor technology TerraVue USA deploys.

Yield Impact

ISU planting date research (Elmore & Abendroth) documents that optimally timed planting — neither too early (cold soil risk) nor too late (lost growing degree days) — is worth $22-$120/acre depending on how far off-optimal the planting date falls. Each day of delay past the optimal window costs approximately 1-2 bu/acre.

Input Savings

Reduced replant costs ($30-$50/acre seed + operations) by avoiding cold-soil planting failures. Field-level data prevents the conservative approach of waiting until all fields are warm enough — enabling growers to plant ready fields first while holding off on at-risk fields.

Operations

Planting crews prioritized by field readiness rather than geographic convenience. Real-time trafficability data (soil moisture + soil temp) prevents equipment getting stuck in wet fields. Cover crop termination timing improved by monitoring actual soil warming rates.

→Why This Matters for Your Farm

University research consistently shows that planting timing is one of the highest-ROI decisions in corn production. Field-level soil temperature monitoring — the same technology TerraVue USA deploys — replaces regional averages with actual conditions in each field, enabling growers to capture the full value of their planting window.

Source: Elmore, R. & Abendroth, L. — ISU Extension, Corn Planting Date Research (2008-2023); USDA-NRCS Soil Climate Analysis Network (SCAN) data; Purdue Extension Corn & Soybean Field Guide.

Midwest and Northeast United States2,000 acres studiedCornSoybeansSpecialty Crops

Leaf Wetness Sensor Networks Reduce Fungicide Applications 20-50% While Maintaining Disease Control

Penn State University (TOM-CAST) & Cornell University (NEWA Program)View source

!The Challenge

Calendar-based fungicide programs — spraying every 7-14 days regardless of conditions — are standard practice across much of U.S. agriculture. Penn State and Cornell research has documented that this wastes applications during dry periods when infection risk is near zero, while sometimes missing critical infection windows during unexpected wet stretches. For Iowa corn growers facing tar spot and gray leaf spot pressure, the question is not whether to spray but when.

Technology Used in This Research

Leaf wetness duration sensors at canopy height, paired with temperature and humidity sensors at field level. Data feeds validated disease forecasting models (TOM-CAST, gray leaf spot models, tar spot risk indices) that predict infection risk based on actual microclimate conditions rather than regional weather station data. TerraVue USA deploys this same leaf wetness and microclimate sensing approach.

Yield Impact

Published research across multiple university programs consistently shows that fewer, better-timed fungicide applications provide equal or superior disease control compared to calendar programs. Applications target actual infection windows rather than spraying preventatively during dry weather when disease risk is negligible.

Input Savings

20-50% reduction in fungicide applications documented across crop systems. Penn State TOM-CAST research: 40-60% reduction on processing tomatoes. Cornell NEWA: 20-40% across multiple disease systems. For corn: 1-2 fewer applications per season at $15-$25/acre per pass saved.

Operations

24-48 hour disease risk forecasts enable growers to mobilize spray crews based on actual conditions. Targeted field-level spraying replaces whole-farm applications. Fungicide resistance management improved through reduced total chemical exposure.

→Why This Matters for Your Farm

Decades of published university research prove that sensor-based disease forecasting works. TerraVue USA deploys the same leaf wetness and microclimate monitoring technology used in these validated research programs, adapted specifically for Iowa corn and soybean operations.

Source: Madden, L., Pennypacker, S. et al. — Penn State TOM-CAST, Phytopathology (1978, updated); Carroll, J. et al. — Cornell NEWA (newa.cornell.edu); Crop Protection Network CPN-2012 (tar spot management guidelines).

North-Central Iowa (Tile-Drained Cropland)2,800 acres studiedCorn/Soy Rotation

Real-Time Tile Drain Monitoring Supports Nutrient Reduction Strategy Compliance and Saves $20-$50/Acre

USDA-ARS National Laboratory for Agriculture & Environment (Ames, IA) & ISU Drainage ResearchView source

!The Challenge

Over 60% of Iowa cropland has subsurface tile drainage — essential for production on the state's naturally poorly drained prairie soils. However, tile drains are also the primary pathway for nitrate-nitrogen loss to surface water. The Iowa Nutrient Reduction Strategy calls for 41% reduction in nitrogen loads from nonpoint sources. USDA-ARS research at the Ames lab has documented that tile drain nitrate concentrations vary dramatically based on soil moisture, rainfall timing, and nitrogen application practices — but without real-time monitoring, growers have no visibility into what is leaving their fields.

Technology Used in This Research

Flow sensors and water quality probes at tile drain outlets, paired with in-field soil moisture sensors at multiple depths. Real-time monitoring tracks both how much water is moving through tile lines and the nitrogen concentration in that water. Data correlates field-level management decisions (application timing, rates, placement) with actual nutrient loss outcomes. TerraVue USA deploys this same tile drain and soil moisture monitoring approach.

Yield Impact

Yield impact is indirect but significant: real-time tile drain data enables growers to identify which fields are losing the most nitrogen, supporting targeted rescue sidedress applications that protect yield while reducing overall nitrogen use.

Input Savings

USDA-ARS and ISU research documents that optimized nitrogen management (right rate, right time, right place) based on real-time field data can reduce nitrogen losses by 10-30% while maintaining yield. At current fertilizer prices, improved nitrogen use efficiency saves $20-$50/acre across the rotation.

Operations

Real-time tile drain monitoring provides verifiable data for conservation practice documentation and nutrient management plan compliance. Data reveals which drainage management practices (controlled drainage, bioreactors, cover crops) are actually reducing nutrient loss on each field.

→Why This Matters for Your Farm

USDA-ARS and ISU research confirm that real-time tile drain and soil moisture monitoring gives growers the data they need to reduce nutrient loss while protecting yield. TerraVue USA deploys this same monitoring technology, helping Iowa operations comply with the Nutrient Reduction Strategy while improving their bottom line.

Source: Parkin, T. & Hatfield, J. — USDA-ARS NLAE, Ames, IA; Helmers, M. & Christianson, L. — ISU Agricultural & Biosystems Engineering; Iowa Nutrient Reduction Strategy Science Assessment (2013, updated 2017).

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