Tillage Verification

Leveraging remote sensing to verify producer reported tillage practices.

🛰️ How are tillage events detected ? 

Monitor evaluates fields for tillage activity in the time period before a commodity crop is planted and after the crop is harvested. Therefore, in most cases there will be two tillage practice determinations (pre-plant and post-harvest) for each commodity crop Monitor detects.

Read more. 

Conflict detection summary table

Producer-reported tillage 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. 

Legend:

	Indicates an agreement.
	Regrow detected a more regenerative, or less intensive, practice than the grower reported.
	Indicates that a disagreement has occurred, but it is not significant or impactful enough to prioritize. This generally applies to disagreements with low confidence or minimal consequences.
	Indicates disagreements, or aggregations of disagreements, that have been prioritized and require attention, typically because they result in an underestimation with a high degree of confidence. For MRV Customers: Only fields and practices marked with this flag will be displayed in the program data review dashboard.
	If data is not available or valid from either the grower or Monitor API for the same practice, that practice is marked as Invalid Data and no comparison is attempted.

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

Step by Step process to flag conflicts

1. Align farmer-reported practice(s) with Monitor’s tillage practice(s).

Monitor reports tillage practices in 3 classes: Conventional till, Reduced till and No till. Aligning on definitions of tillage practices, and how it relates to on-field tillage events can be helpful when getting started. Here’s a general explanation of the three tillage classes reported by Monitor and how they align with farming practices:

• Aligning tillage activity is much easier if dates of tillage events are collected from farmers, but anchoring around pre-plant and post-harvest practices is a good way to create alignment

• We encourage to have farmers explicitly report ‘no till’ practices, rather than omitting tillage activity if a field was not tilled. If farmers do not explicitly report ‘no till' practices, you may have to make assumptions during practice verification if tillage activity is missing.

2. Identify fields where Monitor had low confidence in the tillage practice determination.

Monitor may not provide a reliable tillage practice 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. Residue confidence is 1 or 2 (on a scale of 1-3). Regrow recommends using Monitor determinations when the tillage confidence is 3.

2. The tillage practice reported by Monitor as 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.

3. Flag practices to review

Background on residue percentage:

Monitor uses the amount of residue observed on a field as a proxy for tillage practice. Looking at the residue percent can provide additional context that’s helpful in determining whether there is truly a conflict with the farmer’s reported practice. 

There are various types of tillage methods and implements that result in wide gradients of tillage intensity and disturbance.  The USDA has provided classifications that relate residue observed on fields to tillage intensity, providing guidance that can be applied across projects and regions:

Decision tree for flagging practices: 

1. Typically, the first step in verifying tillage practices is to identify fields where Monitor and the farmer agree. If the farmer-reported practice aligns with the Monitor tillage practice, that practice can be considered verified
2. If there is a disagreement between the farmer-reported practice and Monitor:

1. 1. Determine if the farmer-reported practice is more intense or less intense than Monitor. For example, the farmer practice is more intense if the farmer reports reduced till and Monitor reports no till.

      1. If the farmer practice is less intense than Monitor’s practice, we recommend proceeding with the farmer’s reported practice, considering it verified because it’s the more conservative practice (so long as the practice is in an intervention year). ➖

      2. If the farmer-reported practice is more intense than Monitor’s practice, you can consider the crop type and residue percentage to determine if there is an actual conflict.
         As mentioned above, Monitor uses the USDA recommendations for approximating tillage practice from residue on a field. This is a conservative approach to predicting tillage practice. However, this doesn’t account for expected differences in the amount of biomass produced by different types of crops. For example, cotton produces significantly less biomass than corn, and therefore leaves less residue on a field. Using the same residue threshold to approximate tillage practice for fragile/low-biomass crops as non-fragile crops may not be agronomically reasonable. To account for these expected differences in residue production and persistence, you can optionally use the following adjusted residue thresholds for fragile/low-biomass crops. Note: be sure to reference the crop that actually produced the residue, as it may be different than the crop in the intervention year. For example, residue left on the field before the commodity crop planting is produced from the previous commodity.
         If the residue percentage reported by Monitor falls within the adjusted practice range, and it aligns with the farmer reported practice, it can be considered verified.
         

         Tillage practice	Residue percent
         Common crops in this category	Soybeans, winter wheat, cotton, cereal grains, potatoes, canola, sugarbeets, sunflowers
         Conventional Till	0-15% residue
         Reduced till	15-30% residue
         No Till	30% + residue

      3. The residue percentage reported by Monitor is a summary of the residue over the entire tillage observation period. There’s an uncertainty range around the estimated value, meaning that the actual amount of residue on the field at the time of tillage could fall around the Monitor-reported value.
         If the residue percentage reported for the practice is on the border of the thresholds described above for the farmer-reported practice, you can consider the practice verified. We recommend allowing for +/- 5% difference in residue, since this is within Monitor’s variance range. For example, if the farmer reports reduced till on a corn field, and Monitor reports conventional till & residue percent = 28, we don’t consider that a conflict because 28% residue is within 5% of the threshold between reduced till and conventional till.

      4. Any practices that remain unverified at this stage can be considered ‘conflicts’. However depending on the severity of the discrepancies, some conflicts might be higher prioritythan others .

Why do tillage conflicts occur?

Often times tillage conflicts are the result of unplanned field management due to unfavorable weather conditions, or tillage activity that’s part of another management practice outside of field preparation.

• Loosening soil that gets compacted from driving machinery across the field often looks like reduced tillage via remote sensing

• Flood repair: Farmers often till their field when there is more precipitation/standing water than expected to improve soil drainage

• Incorporating fertilizer (especially anhydrous products) or organic amendments such as manure cause soil disturbance that looks like tillage

• Root vegetables: harvesting root vegetables and planting potatoes cause soil disruption that can look like tillage activity via remote sensing

• Residue removal/silage crops: removing residue, or harvesting the entire plant leaves little to no residue on a field. This looks like bare soil via remote sensing.

All of these practices result in soil disturbance that may impact soil carbon.