For comparison I sent soil samples from the garden and field to International Ag Labs. International Ag Labs does a great job helping their clients develop better soils, not just increase NP&K levels.
There are a couple of test they run that most labs don't. The first is the Formazan Test. This test will tell you how well your soil will digest fertilizer, amendments, and residue. The other is ERGS (energy released per gram of soil). This measures the amount of energy in the soil available for plant growth.
International Ag Labs also computes a Soil Index. The Soil Index measures the overall quality of this soil. It is represented as a 0-100 score on the soil with the potential to show negative numbers if the soil is extremely hostile to growing plants. The Soil Index is simply the total of all points (positive or negative) from all the measurements and ratios on the soil test. The desired level is 50 and greater.
These tests confirm the test from Midwest Labs, low pH 6.5 in the garden, 4.9 in the field. The test also confirms low calcium availability in the field; half of what is available in the garden. Also phosphorus is very low in the field. By having the Formazan test, and the ERGS test done, this gives us a better idea of how to make adjustments to the field.
Recommendations from Midwest Labs, tells us that we need 3.5 tons of ag lime (at a 90% ecce) to make the pH change (remember First Things First, fix your pH). However since most aglime is a 50% ecce, and 25% drifts away you will need close to 8 tons of aglime to change the pH.
The Formazan and the ERGS shows that the digestive capacity of the soil will not handle 3.5 tons of aglime. Applying that much lime to the field will not increase yield for years! It may show a pH and calcium increase in the lab, but plant available calcium will still be low.
Applying lime at a level the soil can handle is the best way to increase yields. You would not add 250 lbs of Nitrogen at one shot to sandy soil with a CEC of 4; it would not be able to store all than N. It would be wasted, this is the same concept with liming.
SuperCal 98G makes it easy and cost effective to lime for increased yields and profits. Applying 3-8 tons of aglime may make a pH change but ROI will be measured in decades. Make your inputs and fields work harder, get better returns, faster on your money, add SuperCal 98G to your fertility program.
The Ag Labs test for the field also recommends gypsum. You may ask why? We addressed this situation in our blog, Improving Water Infiltration. Low salt content reduces structure, creating small pore space, and less permeability. The other reason to add gypsum is, it adds soluble calcium for plants, something this field is lacking. SuperCal SO4, pelletized gypsum makes it easy to spread high quality gypsum.
On a final note, don't be satisfied with ""adequate"" or ""good enough"". In today's agriculture maximizing every acre of land is essential.
The Blogronomist is maintained by Craig Dick, head blogronomist and VP of Sales and Marketing. Here you will find a wide array of blog articles from Craig and expert guests on topics related to soil and crop health, farming, and so much more. If it’s not here, ask us!