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Variability In Weather Affects Key Decisions

By: Andy Nadler

Agricultural Meteorologist, Farmers Edge

One of the greatest challenges in farming is dealing with variability. Soil varies from one field to the next and within a single field. Input and commodity prices change from day-to-day. While these factors will affect productivity, management, and marketing decisions, variability in the weather can completely dictate whether a crop succeeds or fails.

Not only does the weather vary over time, but also from one location to the next. Every farmer knows that the weather is never consistent across the farm. Over the past three years, we at Farmers Edge have been aggressively expanding our weather network to better equip the farmer to deal with this variability. We’re almost at 4000 weather stations!

Contrast this to conventional practices that use weather information from public sources – mainly weather stations located near larger cities or at airports. Weather conditions within the vast areas between those stations gets estimated using various techniques, some more sophisticated than others. Unfortunately, without on-the-ground monitoring, it is difficult to determine how close these estimates are to what occurred.

Take the example below. This map is from FarmCommand – Weather Manager. The map shows some grower fields along with the locations of three local Farmers Edge weather stations. Each station is within approximately 2 miles of one another.

The chart shows the monthly rainfall totals at each station. Notice the differences in rainfall, particularly in June, where Stations 2 and 3 differ by 31 mm (1.2”)! This amount can have serious impacts on soil moisture, yield, nutrient dynamics, even disease, over a small area. Only with field-centric weather can a farmer adapt their management to reflect what is happening in the field.

From May through August, the total rainfall at Station 1 is 193 mm, Station 2 is 174 mm, and Station 3 is 223 mm – a range of 78 mm (3.1”)! If one were to assume that the weather conditions at the airport can adequately represent the variability of such a local area, they would be mistaken.

If one were to base their crop management decisions on regional weather values, they would be neglecting the variability that is always present. Clearly, the choice of weather sources – field-centric versus regional – will influence the accuracy of prediction.

We believe that information collected from the actual field produces the most accurate results – period. Whether it’s historical weather conditions, soil sampling, nitrogen recommendations, growth stage predictions, or disease risk, better and more site-specific information will produce more field-specific results.

Now that’s smart farming!