What Does My Soil Test Say?
Apr 02, 2019
Maybe your fields are finally dry enough to plant , or maybe they are still underwater. Whichever scenario you are in , you are probably wondering how the weather this spring has affected your soil. The best way to find out what is in your soil is by soil sampling , and more specifically , by grid soil sampling. Why?
A grid soil sample provides valuable information to help you place the right amount of nutrients in the right place on the right field. The result is a smart fertility decision , and making smart decisions means more money in your pocket at the end of the season. Whether you are starting a fertility program on new land or wanting to know how much nitrogen or sulfur your field lost due to rain in the off-season , soil sampling will provide a baseline for the field and help you set realistic goals for this year’s harvest.
So where do you begin? Evaluate your soil analysis sheet. There’s a lot of information on one page , so let’s start with the basics!
pH , Nutrients , and Ratios
When reading a soil analysis , pH should be the starting point. Most field crops have an optimal pH range of 5.5-6.5 where nutrient uptake is optimized. If your pH is lower than 5.5 , it may be time to spread lime. This is when you should look at the soil pH and the buffer pH to figure out lime requirements. After pH , the nutrients will be listed. The results are usually listed in parts per million or lbs. per acre and can be used to make a recommendation based on crop planted and your 2019 yield goals. As a general rule , if the results are listed in ppm , you can multiply ppm by two to get pounds per acre.
Once you’ve reviewed the individual nutrient needs , the next step is to take a look at the nutrient ratios. If one nutrient level gets too high in the soil it could affect the uptake of other nutrients. Consider this scenario: In parts of the Mississippi Delta , high magnesium levels are found in the soil which are antagonistic for potassium uptake. In this case , extra potash may be needed to help keep a proper balance. This balance is why a soil test may show adequate levels of a nutrient in the soil , but the same nutrient in a plant tissue sample is deficient. The Mulder’s Chart shows how nutrients affect each other antagonistically or synergistically.
![Mulders.jpg Mulders.jpg](https://storageatlasengagepdcus.blob.core.windows.net/atlas/all-media/greenpoint/news-and-insights/agronomy-news/2019/april-june/mulders.jpg)
Cation Exchange Capacity
Now what about the line that says Calculated Cation Exchange Capacity? A soil analysis also shows cation exchange capacity , often referred to as CECs. CECs are important when making fertilizer applications , chemical application rates , and—with organic matter—can give an understanding of water holding capacity.
A cation is a positively charged ion. Common cations in soil include hydrogen , aluminum , iron , calcium , magnesium , potassium , zinc , ammonium and sodium. A soil’s CEC is the ability of that soil to hold and attract cations. The higher the CEC , the more cations a soil will hold. High clay content and organic matter cause CECs to increase over their sandier soil/low organic matter counterparts as there are more exchange sites or more places a cation can bind on soil colloids. Though it may be the smallest section of a soil analysis , CECs play a major role in determining soil pH , and the timing and rates of fertilizer and residual herbicides.
Are you ready to know what’s in your soil? Contact your local GreenPoint AG for your soil sampling needs , and we will provide a variable rate prescription through Incompass®.
A grid soil sample provides valuable information to help you place the right amount of nutrients in the right place on the right field. The result is a smart fertility decision , and making smart decisions means more money in your pocket at the end of the season. Whether you are starting a fertility program on new land or wanting to know how much nitrogen or sulfur your field lost due to rain in the off-season , soil sampling will provide a baseline for the field and help you set realistic goals for this year’s harvest.
So where do you begin? Evaluate your soil analysis sheet. There’s a lot of information on one page , so let’s start with the basics!
pH , Nutrients , and Ratios
When reading a soil analysis , pH should be the starting point. Most field crops have an optimal pH range of 5.5-6.5 where nutrient uptake is optimized. If your pH is lower than 5.5 , it may be time to spread lime. This is when you should look at the soil pH and the buffer pH to figure out lime requirements. After pH , the nutrients will be listed. The results are usually listed in parts per million or lbs. per acre and can be used to make a recommendation based on crop planted and your 2019 yield goals. As a general rule , if the results are listed in ppm , you can multiply ppm by two to get pounds per acre.
Once you’ve reviewed the individual nutrient needs , the next step is to take a look at the nutrient ratios. If one nutrient level gets too high in the soil it could affect the uptake of other nutrients. Consider this scenario: In parts of the Mississippi Delta , high magnesium levels are found in the soil which are antagonistic for potassium uptake. In this case , extra potash may be needed to help keep a proper balance. This balance is why a soil test may show adequate levels of a nutrient in the soil , but the same nutrient in a plant tissue sample is deficient. The Mulder’s Chart shows how nutrients affect each other antagonistically or synergistically.
![Mulders.jpg Mulders.jpg](https://storageatlasengagepdcus.blob.core.windows.net/atlas/all-media/greenpoint/news-and-insights/agronomy-news/2019/april-june/mulders.jpg)
Cation Exchange Capacity
Now what about the line that says Calculated Cation Exchange Capacity? A soil analysis also shows cation exchange capacity , often referred to as CECs. CECs are important when making fertilizer applications , chemical application rates , and—with organic matter—can give an understanding of water holding capacity.
A cation is a positively charged ion. Common cations in soil include hydrogen , aluminum , iron , calcium , magnesium , potassium , zinc , ammonium and sodium. A soil’s CEC is the ability of that soil to hold and attract cations. The higher the CEC , the more cations a soil will hold. High clay content and organic matter cause CECs to increase over their sandier soil/low organic matter counterparts as there are more exchange sites or more places a cation can bind on soil colloids. Though it may be the smallest section of a soil analysis , CECs play a major role in determining soil pH , and the timing and rates of fertilizer and residual herbicides.
Are you ready to know what’s in your soil? Contact your local GreenPoint AG for your soil sampling needs , and we will provide a variable rate prescription through Incompass®.