Why we use tarp controls

Tarp controls let us compare sprayed and unsprayed crop side by side.
This shows if the spray recommendation worked — and how much the nutrient status improved.

Each tarp gives us two extra data points:

• One from the treated area
• One from the unsprayed area under the tarp

This helps validate the spray and improve long-term nutrient planning.
Tarp controls are part of the pilot and are 90% covered by PRIA’s advisory subsidy.

Before you spray

To take part in tarp control:

• Sign the Farmer Participation Agreement
• Then sign the Tarp Control Advisory Agreement in ePria
  (This must be done before your first tarp-controlled spray)

We’ll create the ePria contract and check your eligibility before the first spray control. We will let you know as soon as we have it prepared. .

Each farm and field in the pilot will receive 4 tarp control evaluation reports throughout the season.
For each report, we apply for 3 hours of advisory service support through PRIA.
You only pay the 10% co-payment — the rest is covered by the subsidy.

What you need

• One tarp (around 4×3 meters) per field
• Tent pegs or weights to hold it in place
• 2 flags or markers to mark the corners
• Your phone to send a GPS pin (Google Maps or OneSoil)

When to do it

Only set up the tarp after you’ve received a spray recommendation.
Once the timing looks good for spraying — and before the sprayer goes out — follow the steps below.

Step-by-step

1. Lay down the tarp
   Pick a spot that represents the field’s general condition — not near field edges or unusual patches.
   Lay the tarp over the crop and fix it with pegs or weights.
2. Spray the field as usual
   Spray right over the tarp — it will block the foliar application underneath.
3. Remove the tarp
   Same day or next morning.
   This leaves a small patch of crop that hasn’t been sprayed.
4. Mark the corners
   Place a flag at opposite corners of the control area.Now when the leave samples will be taken from the space between the flags, to make sure only untreated leaves are sampled. 
5. Send the GPS pin to CropVise
   Use Google Maps or a scouting pin in OneSoil.
   If you forget, just send it as soon as you can — but it’s best to do it the same day.

What happens next

CropVise will:

• Send someone to take sap samples from:
  • The unsprayed tarp control area
  • A sprayed area about 15 meters away (to avoid overlap or drift)
• Compare both samples in your report
• Show how well the spray worked and how the crop responded

Every tarp helps improve both your in-season recommendations and your long-term nutrient planning.

It takes just a few minutes to set up, but gives us the data we need to make better decisions for your crop and soil.