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. 

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

Step by step process to identify tillage conflicts

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

The first step is to align farmer & Monitor data based on timing to ensure the right events are being evaluated. Monitor observes fields for tillage activity based at two key time periods in the cultivation cycle: post-harvest (following the harvest of a commodity) and pre-plant (before the planting of the current commodity). Regrow suggests to align farmer-reported tillage events to this time cycle for equivalent evaluation.

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:

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.

When the post-harvest or pre-plant tillage evaluation falls into this category, 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 on fields to tillage intensity, providing guidance that can be applied across projects and regions:

*Common crops in this category include: Soybeans, winter wheat, cotton, cereal grains, potatoes, canola, sugarbeets, sunflowers

Decision tree for flagging practices: 

1. Start by verifying tillage practices 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 optionally check if the practice is on the border of getting classified into another practice. 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.

1. 1. 1. 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.