Verification Strips

Roberto N. Barbosa, Burns, Dennis

An example of corn verification nitrogen strips demonstration.

An example of NDVI data captured using satellite imagery.

Producers’ use of verification strips in a field as a comparison with their standard application rate is a way to define management strips or learn what precision ag has to offer on their farm. A verification strip is a single-rate application applied as one or two passes placed at one or more locations in the field. Yield monitor data are collected from the strips and sorted out using polygons created from the verification-strip application. The amount of information available about the field (soil type, fertility, elevation, ECa data) reflects on the analysis carried out on the yield data.

Producers who have no other precision ag equipment except a yield monitor can use this demonstration to learn what to look for on yield maps and how to use the data to improve their own operations. It is easier for a producer who has little experience with precision ag to learn from one strip location in the field. An example of a simple demonstration of this type is nitrogen-rate strips for corn or cotton. At a point in the field, the producer lowers the nitrogen rate by 20 lbs. of N and applies a round. He then raises the N rate to 20 lbs. over his standard N rate and applies a round. The producer marks the strip locations and resets to his standard N rate and continues across the field. GPS points are taken on each end of the field to designate the rate strips (farmer standard, -20 lbs N, + 20 lbs N, farmer standard), and application polygons are created. After yield data have been collected and placed in the corresponding application strips, the producer can look for variations among the strips. If more information other than the producer’s knowledge of the field is available, the data could be compared according to those parameters. The objective of this demonstration is not to find a nitrogen rate but to educate the producer in what his equipment can show about his crop and encourage him to expand the use of precision ag in future cropping operations.

With multiple strip applications across a field, a producer can use the results along with other field information to create management zones. Depending on the product applied, the producer can create prescription applications to apply only to the zones where returns are justified or where the rate is best utilized for the highest return. An example is multiple applications of a nematicide in a cotton field. Using the yield data and other indicators, the zones (treated and untreated) would be defined by the returns from the nematicide application.

With a yield monitor, a producer can work in fields on his own farm to increase his profitability through increasing his knowledge of what is happening in those fields. Whatever their goal for using verification strips, producers must realize that precision ag is an ongoing process and data collected each year will help them refine their operations.

If a producer would like to use this demonstration on his farm, he can contact one of the geo-spatial agents for the LSU AgCenter to assist in setting it up and following through with the analysis of the yield data.
11/21/2009 3:17:44 AM
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