Farms.com Home   Ag Industry News

What is an acceptable change in soil test levels?</

While a small change in these levels shouldn’t raise an alarm, be sure to follow up if you see a significant change

By Patrick Lynch
Farms.com

If you are soil sampling you should track how levels change over the years. Ideally, the same person or lab should take the samples year after year. Then you can see if the levels change.

If a lab is working at top efficiency, there can be a 25 per cent difference in the results from one day to the next. Thus, any test number could be plus or minus 12.5 per cent. Thus, a soil test of 50 could be plus or minus 12.5 per cent, so could be 44 to 56.

So if your soil test level for P has dropped from 56 to 42 ppm that would be a 25 per cent drop. At those high levels a 25 per cent drop is no problem. Both levels are very high. Neither levels are responsive – except for a starter.

On the other hand, if you soil is testing 12 ppm P, a 25 per cent variation would mean it could be 9 to 15 ppm. Again, no big problem, since at 10 or 14 ppm you should be applying more than removal rate.

Same for K. A soil testing 100 could be 90 to 125. At these levels you should be applying at least enough to cover removal rates – and possibly a bit more. If you are testing 300 for K and drop to 250 – no problem.

But if your soil is testing 28 for P and suddenly drops to 14, there is a problem.

What if I have an unreasonable change in soil test levels?

If your soil test levels for P have dropped from say 28 to 14 or risen from 14 to 28, you need answers. If you have ruled out all possible explanations for change in soil test levels – such as you did not apply sludge or high poultry manure rates, used a plastic pail, and sampled at the same depth as the last time – call the lab.

Most labs keep soil samples for a few weeks after analyzed. If something doesn’t make sense, call the lab and ask for a repeat analysis.


Trending Video

How American Farmers Harvest 9.97 Million Tons of Rice by Machine

Video: How American Farmers Harvest 9.97 Million Tons of Rice by Machine

How American Farmers Harvest 9.97 Million Tons of Rice by Machine

Step into the world of large-scale rice farming with this eye-opening farming documentary! Discover how American farmers harvest 9.97 million tons of rice by machine, utilizing advanced agricultural technology to maximize efficiency and productivity. This video takes you on a journey from the rice fields to the processing stage, showcasing the innovative techniques that help meet global food demands.
Watch as American farmers harvest 9.97 million tons of rice by machine, using state-of-the-art harvesters designed to work swiftly and precisely. This farming documentary explores the entire rice production process, from planting and irrigation to harvesting and milling. See how automation and AI-driven machinery assist farmers in reducing labor costs while improving yield and sustainability.
This farming documentary also highlights the environmental considerations and resource management techniques used to ensure sustainable rice production. By focusing on how American farmers harvest 9.97 million tons of rice by machine, the video demonstrates the balance between technological advancements and responsible farming practices.
Whether you’re an agriculture enthusiast, a fan of modern machinery, or simply curious about where your food comes from, this farming documentary provides an in-depth and engaging experience. See how American farmers harvest 9.97 million tons of rice by machine, transforming raw grains into a staple food for millions. Don’t miss this must-watch exploration of the incredible innovations shaping the future of rice farming in this insightful farming documentary!