Introduction

Many of our customers use Chandler Biocat 1000 to manage problems with excess crop residue above the soil surface. These benefits include fewer problems with residue clogging planting and tillage equipment, less wear on tires, reduced pressure from weeds and volunteer corn, and diminished habitat for residue-borne diseases and insects. These customers also noticed improvement in their soil health and fertility, but these changes were harder to measure in past. Thanks to new tools like the Solvita CO2 respiration test, we can now precisely measure the biological impact of the Chandler products. In this paper, we report the results from three separate on-farm tests conducted in 2016 and 2017. In each case, Biocat 1000 was applied to corn stalks at 16 ounces per acres, which costs about $10 per acre. The first study shows the early benefits from a spring application, and the other studies show the full-season value of residue decay.

Corn Stalks Treated in the Spring (Champaign County, IL)

Test Summary: One of our long-term customers applied Chandler Biocat 1000 (16 ounces per acre) to most of his corn stalks in mid-May, 2017, and parts of the field were left untreated. He planted no-till soybeans one week later, and all of the beans received an in-row (2 X 2) treatment of Chandler Soil (8 ounces per acre). Five weeks later, the farmer noticed there was less residue in the areas treated with Biocat 1000, and the treated corn stalks and cobs were very brittle. To measure the differences in decay activity across the field, we collected soil samples from the treated and untreated plots one week later. The average soil test results from the treated and untreated plots are:

Biological activity measureTreatedUntreatedIncrease
Solvita CO2-C respiration110.6 ppm88.3 ppm+25.3%
Soil health score29.421.4+37.4%
Soluble carbon186.5 ppm202.4 ppm-7.8%
Total available nitrogen57.6 ppm49.2 ppm+17.1%
Mineralizable nitrogen82.6 #/acre69.1 #/acre+19.5%
Total available phosphorus48.5 ppm44.2 ppm+9.7%
Inorganic potassium165.0 ppm166.5 ppm-0.9%

Remarks: The conditions for biological decay were very favorable in eastern Illinois during May and June, and Chandler Biocat 1000 still generated over 25% more microbial activity in the treated plots. Note that there was less soluble carbon in the treated plots because the larger microbial populations consumed more carbon as energy. Although more microbial activity also requires more nitrogen, the decay organisms released more N than they need, and the treated plots had more nitrogen and phosphorus after six weeks. There is almost no change in the potassium values because much of the K is in the lower corn stalk that takes longer to decay. If we value the additional N and P released at commercial fertilizer prices, we find that the value added by Biocat 1000 in just six weeks is worth about two times the product cost:

NutrientAmount Added by Biocat 1000Fertilizer Value
Nitrogen30.2 pounds per acre$10.59
P2O519.9 pounds per acre$7.94
Total fertilizer value of additional nutrients released by Biocat 1000 in 6 weeks$18.53

Corn Stalks Treated in the Fall (central Michigan)

Test Summary: During late October, 2016, Chandler Biocat 1000 was applied to corn stalks in half of the field at 16 ounces per acre, and the entire field was treated with Chandler Soil at 16 ounces per acre. Soybeans were planted in May, 2017. We collected soil samples from the plots in September, 2017:

Biological activity measureTreatedUntreatedIncrease
Solvita CO2-C respiration71.0 ppm66.4 ppm+6.9%
Soil health score13.711.4+20.2%
Soluble carbon242.3 ppm217.7 ppm+11.3%
Total available nitrogen28.7 ppm22.6 ppm+27.0%
Mineralizeable nitrogen42.6 #/acre32.7 #/acre+30.3%
Total available phosphorus31.1 ppm27.8 ppm+11.9%
Inorganic potassium264.0 ppm209.0 ppm+26.3%

Remarks: Although most of the decay activity was finished by early September, the treated plots had higher levels of CO2 respiration, soil health, and soluble carbon. The untreated plot had good nutrient levels because it had been sprayed with Chandler Soil, and the soil had more than half of the N and P and all of the K required to produce 200 BPA corn. However, Biocat 1000 released even more nutrients from the residue over the 10 months after treatment. If we value the additional N, P, and K released at commercial fertilizer prices, we find that the value added by Biocat 1000 in 10 months is worth about six times the product cost:

NutrientAmount Added by Biocat 1000Fertilizer Value
Nitrogen22.9 pounds per acre$8.02
P2O514.8 pounds per acre$5.93
K2O132.0 pounds per acre$46.20
Total fertilizer value of additional nutrients released by Biocat 1000 in 10 months$60.15

2016 Corn-on-Corn Residue Trial (Hancock County, IL)

Test Summary: Chandler Soil and Biocat 1000 were applied to corn stalks (16 ounces per acre of each product) during the first week of May, 2016, and three treated and three untreated plots were planted to corn one week later. In early September, we collected soil samples from the plots, and the average test results are:

Biological activity measureTreatedUntreatedIncrease
Solvita CO2-C respiration110.9 ppm108.0 ppm+2.7%
Soil health score78.851.4+53.3%
Soluble carbon691.6 ppm162.2 ppm+326.4%
Total available nitrogen334.2 ppm99.8 ppm+234.9%
Mineralizeable nitrogen164.9 #/acre147.7 #/acre+11.6%
Total available phosphorus30.0 ppm28.1 ppm+6.8%
Inorganic potassium130.0 ppm116.0 ppm+12.1%
Harvested corn yields205.0 BPA200.0 BPA+5.0 BPA

Remarks: By early September, the biological activity in all plots remained high (over 100 ppm CO2), and there was only a slight difference in CO2 because the decay activity was largely complete. Based on the other measures, there had been more active decay in the treated plots during the season. In particular, the soil health score in the treated plots was over 50% higher, soluble carbon was over 300% higher, and available N was over 200% higher. Also, the treated plots produced 5 BPA more corn.