Acres & Assets | Nurturing the Next Crop

Operating a combine during the harvesting of the current crop is a good time to assess what is working and what isn’t working when it comes to optimizing yields for the next season.  Prior to the advent of yield maps, grid soil sampling, and other technologies, one of the best vantage points to size up the crop outcome and field potential was while sitting in the combine cab.  But today, there are many more ways to assess the current crop and make plans on how best to nurture the next crop.

When running the combine through grain crops prior to today’s various technological advances, I could visually see and experience variations within fields and the factors limiting crop yields.  I could see crop height grow shorter in the places with lower quality or eroded soils and in areas that ponded water sometime during the growing season.  The threshing noises of the combine would grow quieter in those places where yields were lower and once into a better crop, the noise level would pick up again as more crop and grain went through the combine.  

I not only observed variations and yield limiting factors while running the combine, but also during all the other trips over the field doing tillage and planting.  What mattered most was deciding what could be done for the next crop to mitigate or eliminate the yield dragging problems.  Did I need to put in a waterway or terraces to stop erosion or drainage tile to take care of the wet spot.  I also looked at other yield limiting factors such as low fertility or a ph level out of balance.

Today’s farmers have many more tools and much more information at their disposal to address yield limiting factors and to better nurture the next crop.  To assess limiting factors, farmers and their advisors can turn to the yield maps generated during harvest, detailed soil maps,  productivity assessments for each field, and fertility tests.   Nurturing a crop to its fullest potential takes informed decision making and then doing the right things at the right times.  One of the first and most important steps in optimizing yields is knowing the fertility needs of each field.  The begins with good soil test information.  

How fields are sampled and tested for nutrients and ph levels has changed dramatically over the span of 50 years.  When I started farming, it was common to combine small amounts of soil taken from several places across a 40 acre field into one representative sample which would be taken to the county extension office for readings on just two nutrients and the ph level.  The results from this one sample would then guide the amount of fertilizer or lime spread at a uniform rate across the whole 40 acres.  

The next jump in soil testing that I started doing was to take multiple soil samples from identified areas of a field with similar soil types and tilth.  Then I could use the test results to apply phosphorus, potassium, and lime in varying amounts to similarly grouped segments of the field.  The thinking was to match the yield potential of specific soil types to the needed fertility to produce the best yields.  This took extra work to map out the field with the test results and then apply the fertilizer myself according to the different rates.  

During the 1990’s the current soil sampling technique was developed in which several soil probes were taken from small areas (typically two acres more or less) which were gridded out over a field through GPS programs.  Soil test results are plotted within each grid which provides a much more detailed analysis of the fertility available in the soil across differing areas of the field. Target yield goals and maximum application rate information are entered into a program that has the soil test results by the grid.  A spread map can then be generated from the information that will vary the rate of fertilizer applied in each grid.  Variable rate application is used for potash and phosphate fertilizers and lime.

Soil sampling and testing is not a 100% accurate science nor is the level of fertility in a field an absolute indicator of final yields.  New techniques and practices are being developed that will continue to improve fertility optimization.  Farming practices, timing of planting, weed control, temperatures during the growing season, and the timing and amount of rainfall all have an impact on crop yields no matter the fertility levels in a field.  However, having optimum levels of major nutrients and some micro nutrients helps improve the odds for the best yields.  Proper fertility helps plants survive and yield better during weather extremes whereas if fertility levels are low, plants will not be as healthy during weather challenges resulting in lower yields.  

Nurturing next year’s crop starts in the combine with a farmer’s observations and for many producers, yield maps and information from the current crop.  In the planning for next year, a farmer will look at soil tests and agronomic recommendations to apply the right amount of fertilizer, not more and not less, required to optimize yields.  Other decisions will follow during the fall and winter leading up to planting time in the spring.  All are aimed at nurturing a crop to its fullest and most efficient potential.