Process For Estimating Crop Yield




The walnut has been dated as far back as at least 7000 B.C.  The ancient Romans called it “Jupiter’s royal acorn” for its large shell and explicit dark to light color which made it known as the “royal nut” as it was often reserved for the upper class.  In time, the English found these delicate nuts and traded the walnut through ports around the world, thus making the “English Walnut” known throughout the world. (

It is believed that the first walnuts cultivated in the United States were by Franciscan Fathers in the late 1700’s in California.  Given that California’s climate is similar to the Middle East and Mediterranean, the walnuts flourished.  Today, the San Joaquin Central Valley is the primary growing region for walnuts and the state of California accounts for 99% of the US supply and 2/3 of the world’s production. (

As with any crop grown, there are many factors that can affect the growers yield such as: temperature, water availability, pests, and diseases.  It is predicted that the acreage and tonnage of walnuts will increase to meet the increase in consumer demand for this healthy and delicious nut.  Therefore, a walnut farmer in today’s industry cannot miss the opportunity to have a healthy producing orchard.

Any farmer will tell you, it is difficult to estimate crop value before harvest.  There are several aspects of this difficulty including:

  1. Historical patterns do little to account for present day conditions
  2. There is no way to readily obtain real time information for crop yield estimation
  3. There is no way to effectively communicate this real time information.


With todays drone technology it is possible to help walnut farmers to determine the estimated percent of their trees that are healthy and producing, but cannot estimate the amount of meat within the nut. The Process For Estimating Crop Yield, or Remote Forecasting system, can be another tool in the walnut farmer’s toolbox to allow for estimating the potential yield and value of the nuts on their trees.



Special features

  • Provides an estimated crop value months in advance of USDA reports
  • Detects higher producing trees vs. lesser producing trees
  • Provides a tree by tree analysis of productivity
  • Potential to be used on other nut species
  • Potential to be used to monitor crop health throughout the season




The goal of any farmer is to produce the best, most profitable crop yield each year.  The eternal battle against pests, plant diseases, too much or too little rain, and Mother Nature in general must be fought and if not won, then at least a détente must be reached.  The ever expanding capabilities of drones must be taken advantage of, whether in spraying for pests and diseases, checking the moister content of the soil, or monitoring the temperatures in the fields and orchards.  While all of this is helpful, it doesn’t help the farmer to estimate the all important final yield which will determine financial success or failure each season.  The Process For Estimating Crop Yield can take the current technology a step further and help by providing an insight into just how productive the orchard is early enough to allow the famer to correct a problem before the problem is too advanced to correct and save the crop.


The Process For Estimating Crop Yield begins with arranging for an unmanned aerial vehicle (UAV or drone) with a digital single-lens reflex high speed multi spectral camera fitted with a near-infrared (NIR) filter.  There are an estimated 144 companies that provide drone enabled surveying of agricultural fields who can provide the basic equipment and personnel to perform the scan.  If you are building your own system you will need equipment for the command center: tables, chairs, flight computer, and drone equipment: UAV, landing pad, controller, first-person view goggles, radio, camera and trigger, and batteries for all.

The scan should be performed between May 1 and July 29th, on a day with great sunlight, few clouds and calm winds between 10am and 2pm for optimal light.  The goal is to fly over fields when the trees are at the peak of health which is in the summer time.  The time of year is just as important as the time of day to receive the most optimal light to make the data interpretation very accurate.  When the day has been chosen, the flight plan can be built with mission planning software on the flight computer to map the area to be scanned. Once the drone is set with the attached camera, all systems are go for flight.  The systems auto-pilot can take over after takeoff allowing a two man team to monitor the equipment and watch the sky to ensure a safe flight. The most important piece of equipment is our censor which is a DSLR high speed multi spectral camera that has been fitted with a NIR filter capable of taking a digital photo every second at a clarity of two centimeters in detail from an altitude of four hundred feet to take the normalized difference vegetation index (NDVI) images of a field of walnuts, forming a map of the field from the NDVI images.

The NIR NDVI images are sent off and processed by a team of certified professionals that specialize in NDVI data processing.  The data is interpreted based upon the ratio of the field that is of High NIR signature.  Once the data is finished processing the user can interpret a mosaic showing the health of the trees based on a color scale.  If 90 percent of the field shows a high NIR signature that means the field is functioning at a 90 percent capacity.

Next, we calculate the meat yield.  The walnut grade is determined by its variety, the most common being the Chandler variety which is graded out of 47.  To calculate the meat yield, multiply the capacity and the yield.  47 multiplied by 90% equals a meat yield quality grade of 42.3.  Since environmental conditions and farming practices are the main two influences of plant health only one field of each variety is needed to give a meat yield assessment.

For quantity, we need a maximum weight, or amount that was kept and shipped.  The farmer should be able to provide their best record year, meaning the most kept.  That number will stand for a 100 percent health rating (a very high meat yield); maximum weight means tons per acre.  For example, if 2.2 tons per acre was the maximum weight the farmer ever had on record, than take the tons per acre – 2.2 tons – multiplied by the health assessment – 90 percent – which equals 1.98 tons per acre.  Then, multiply 1.98 tons per acre by the amount of acres in that field.  That gives the total weight in tons.

To be clear, from every load of walnuts that is shipped out for processing, 100 randomly chosen nuts are examined from each load for quality and graded on the afore mentioned scale.  They then average the total grades from each load giving the final meat yield, which is what the farmer is paid upon. It is this final meat yield that we can see in the summer time, many months before harvesting.

The flights using the Process For Estimating Crop Yield, or Remote Forecasting, can help to evaluate the health quality of the trees, in orchards seven years or older for accuracy, and the health quality of the trees reveals the quality of the nuts that will be harvested and shipped.

The Process For Estimating Crop Yield also has potential for evaluating other perennial nut species, only needing to find the “peak time” for the particular species and its specific harvest time, thus expanding the potential market for this technique.


An additional benefit of the Process For Estimating Crop Yield is that is can be used for “health checks”.  This would be additional flights after peak season, perhaps once a month, allowing the farmer to continue to track the crops overall health as the year goes on, as well as tracking the weight so the farmer can estimate how many tons could be left on the trees after the harvest is complete.  The farmer can simply request a “health check” at any time they choose.  This can determine if a second pick is worth doing.  To be clear this is done only to track the weight, the meat yield at “peak time” always remains the same.


For example, if a farmer has a low health rating at peak time and sees his crop further decaying later thanks to a “health check” flight, then the farmer would be advised to think about harvesting the crop a little sooner than normal to help save the weight and to ensure the meat yield remains where it was at the peak time.  The same goes for the opposite, if a farmer with a high health rating at peak time discovers later, thanks to a health check flight, that his crops health is holding on, then a farmer would be advised to go a little later than normal to maximize the weight along with the strong meat yield.


Materials needed to produce the Process for Estimating Crop Yield:


  • DSLR camera converted for NDVI to detect  plant stress – Red Green NIR for data processing
  • Data processor such as Drone Deploy
  • Multirotor aircraft made to carry DSLR cameras
  • Flight batteries and charging equipment
  • Flight controller – Pixhawk Orange Cube is ideal for mapping
  • Radio for control
  • Laptop for planning missions and uploading images
  • Landing pad
  • Trigger for the camera – Seagull System recommended
  • Table and chairs for the command center



The Process For Estimating Crop Yield  is covered by United States Utility Patent: 11,625,793



For additional information, licensing opportunities, and a full prospectus on the Process For Estimating Crop Yield  contact:


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