Program data review
      Back to home
      1. Knowledge Base
      2. MRV
      3. Program data review

      Cover Crop Verification

      Leveraging remote sensing to verify producer reported cover crops practices.

      🛰️ How are cover crops detected ? 

      Fields are evaluated for cover crops after harvest to before planting of the next commodity crop. The strength and extent of green cover is assessed between periods of senescence and emergence of commodity crops therefore the observation window to determine a cover crop is dynamic based on the crop cycles of the field. We require a minimum of 8 weeks between two commodity crops to avoid inclusion of temporary regrowth, weeds and volunteers in cover crop determinations. We also account for temporary regrowth, weeds and volunteers through regional parameters that reflect the level of growth in surrounding natural herbaceous vegetation.

      Monitor_cover_crop_detection_method

      Cover crop detection summary table

      Producer-reported cover crop practices during the program reporting period are compared with Monitor API observed practices. A prioritization framework is applied to categorize agreements, disagreements and aggregations of disagreements to determine their status based on their impact, severity, and confidence level. 

      Farmer practice Monitor practice Monitor confidence Considerations Conflict priority
      Cover crop Cover crop 3   ✅ verified
      No cover crop Any practice N/A   ✅ verified - not applicable
      Cover crop No cover crop 3   ❗Conflict
      Cover crop Potential cover crop 3 Emergence: `weak emergence` or `no vegetation` 🔶 Conflict
      Cover crop Potential cover crop 3 Emergence: `good emergence` or `strong emergence` 

      ⚠️ Warning - cover crop likely, but did not establish/thrive
      Cover crop Not applicable N/A   ⚠️ Warning - - perennial crop detected
      Any practice Any practice 1-2   🏳️ No data - Alternate verification method required
      Any practice No data N/A   🏳️ No data - Alternate verification method required

      *For MRV Customers: Only fields and practices marked with this flagged will be displayed in the program data review dashboard. 

      For MRV customers: Only MRV fields with signed contracts and complete data collection are analyzed.

       

      Step by Step process to verify practices

      This section is mostly relevant for API customers, or MRV customers wanting to understand more about Regrow's conflict flagging logic.

      Note - this logic is only applied to fields where a cover crop intervention was selected by the farmer, or where the farmer reported a cover crop practice.

      1. Align farmer-reported practice(s) with Monitor’s cover crops determination.

      To align the cover cropping practices, it can be helpful to anchor practices to a season. For example, assigning a farmer reported cover crop and a cover crop reported by Monitor to winter 2023 can be a helpful way to align the two events. Alternatively, grouping practices reported by the farmer into a harvest-to-harvest cultivation cycle can be a good way to align the cover cropping events as well.

      Considerations to keep in mind:

      • It’s helpful to collect the planting and termination dates of cover crops from farmers.

      • You may want to pre-filter fields to only those that have a cover crop practice reported by the farmer. There’s no need to run the verification analysis on fields if there wasn’t a target practice indicated.

      • Monitor only observes fields when there is at least 8 weeks between two commodity crops. If you farmers are planting short-season cover crops or catch crops, plan to use an alternative method of verification on those fields.

      2.  Check if Monitor detected the farmer-reported cover crop as a commodity.

      Monitor's CropID model is trained to detect all common commodity crops. This includes crops that can be grown as both a cover crop and a commodity (such as winter wheat and rye). When Monitor can detect the crop type, it will report it as a commodity crop. For example, if Monitor 'sees' winter wheat it will always be reported as a 'main crop' by Monitor even if it was planted as a cover crop. The PDR logic takes this into account.

      • Check if Monitor reported a commodity crop that matches (or is very similar to) the cover crop reported by the farmer.
      • If so, this can be considered a confirmed cover crop practice ✅

      3. Identify fields where Monitor had low confidence in the cover crop determination.

      Monitor may not provide a reliable cover crop determination when there is not enough high-quality data available to make a determination (ex: high frequency of cloud cover). This can show up in the Monitor field results in two ways:

      1. Cover crop confidence is 1 or 2 (on a scale of 1-3). Regrow recommends using Monitor determinations when the cover crop confidence is 3.

      2. The cover crop class reported by Monitor is no data, indicating that there was not enough remote sensing data available to make a determination.

      In these cases, we recommend using an alternative method of practice verification.

      4. Flag practices to review

      Background on cover crop data points

      When evaluating cover crop activity on a field, we look at the following data points reported by Monitor:

      1. Cover crop class: Cover crop classifications are a statistical summarization of the ‘greenness’ on a field, considering the emergence quality of the cover crop as well as the vigor and persistence over the crop crop period. To qualify as a cover crop, the field must meet or exceed regional greenness thresholds.

      • cover crop: A cover crop was detected, and it was established & persistent enough to meet or exceed regional greenness threshold (the crop was as green or greener than the surrounding area).

      • potential cover crop: Greenness was detected on the field during the cover crop observation, but it was not persistent enough or did not thrive to meet regional greenness threshold. This is usually the result of weed growth, volunteers, temporary re-emergence or cases where a cover crop was planted but did not establish.

      • no cover crop: A cover crop was not tracked. This is typically indicative of exposed soil.

      • no data: Not enough data was available to make a cover crop determination during the time period.

      • cover crop not applicable: A cover crop is not expected to be planted on the field because a perennial commodity was detected.

      2. Mean NDVI: The mean NDVI is the average monthly greenness over the cover crop observation period. For example, if there are 6 months in the cover crop observation, the NDVI for each month is averaged to give a score for the field.

      This is especially useful for understanding 'potential cover crop', as it can be used to understand how strong/prevalent the green signal was.

      3. Emergence Quality Score: A key metric that evaluates how well a cover crop emerged during the first two months of the observation period. This score helps distinguish between crops that initially emerged strong but later died (e.g., due to early winter kill) and those that had weak emergence and failed to establish. The score includes the following discrete values: no vegetation, weak emergence, good emergence, and strong emergence.

      Decision tree for flagging practices

      The section below explains how we arrive to the summary table described at the top of the page.

      1. The first step is to identify fields where the farmer reported practice and the Monitor detected practice agree. For example, if Monitor reports a determination of cover crop for the field, and the farmer reports that they planted a cover crop during the same time period, there is agreement. These fields can be considered verified. ✅

      2. If there is a disagreement between the farmer-reported practice and Monitor:

        1. First, identify fields where the farmer-reported practice is more conservative than the Monitor-reported practice. For example, if the farmer reports no cover crop and Monitor reports potential cover crop or cover crop, the farmer practice is more conservative. This typically happens if Monitor picks up weed growth over the off-season. Fields in this category can be considered verified. 

        2. Then, check fields where Monitor reported a potential cover crop practice. This classification indicates that there was something green growing on the field, but it wasn’t ‘green’ enough to meet the threshold for calling it a cover crop. Typically, this means that the field’s greenness wasn’t greener than the average of the surrounding region. This type of disagreement doesn’t necessarily indicate there’s a conflict with the farmer’s report. If the farmer reported a cover crop practice, and Monitor reports potential cover crop it could be an indication that the cover crop did not establish strongly, or thrive for the entire period.

          You can use the emergence quality and NDVI mean from Monitor for additional agronomic context to help guide decision making.

          Monitor cover crop class

          Emergence quality

          Ok to verify?

          Recommended next steps:

          Potential cover

          good emergence, strong emergence

          Possible verified

           

          Require additional proof from the farmer that the green cover was a planted cover crop, such as field images or seed receipts.

          Potential cover

          weak emergence or no vegetation

          Additional verification

          Risk to over-reporting carbon outcomes

          Require additional proof from the farmer of cover crop planting.

          If theres proof of practice, we recommend additionally shortening the growing period of the cover crop used for quantifying carbon outcomes, to reduce risk of over-estimating carbon impact.

          Internal: How much to shorte
           

        3. Then, look at fields where Monitor reports no cover crop and the farmer reports that there was a cover crop practice.

          Pro tip: Check the commodity crop that the farmer planted first. Some winter crops will be detected by Monitor as a commodity crop, and therefore won’t be reported as a cover crop. This is true for winter wheat, rye, barley, oats, and other cereal grains. If the farmer reported one of these types of cover crops and Monitor reported it as a commodity crop, you can consider the practice verified (as long as it’s not harvested for sale). ✅

        4. Otherwise, if Monitor does not detect a cover crop, this is the strongest type of disagreement and is considered a true conflict. ❌

      Why do cover crop conflicts occur?

      The most common cause of conflicts results when farmers attempt to plant a cover crop & seed the field, but the crop does not emerge or establish. A few common reasons for this:

      • Drought/dry season meant the cover crop did not get the water needed to grow

      • Early frost winter-killed the cover crop sooner than expected

      Note: you could also see a ‘potential’ cover crop when the farmer didn’t plant one, in cases of weed growth or short-term commodity regrowth.