The problem explained by you is not directly related to peroxdase, but it is due to Soil Sickess. Some books are avaialble now soil sickess and it has benn reported in several cop spp and even Fruit trees and forestry trees, where it is called Replanting Problem. You can contact me at [email protected] and visit the website www.allelopathyjournal.org

Prof. S.S.Narwal

Horseraddish produces peroxidase in high yields to deal with the natural production of hydrogen peroxide during normal metabolism. It is more likely that if peroxidases are accumulating in the soil, they are directly due to the presence of horseraddish itself and should have no detrimental effects as they deal with strong chemical oxidisers. It is highly possible that the soil is mineral deficient as MA suggests. However, if the addition of Sulfur has been taking place over several seasons, it is also possible that the soil has been acidified due to the production of sulfuric acid by microorganisms (chemoautotrophs). Check the soil pH and compare to the optimal growing conditions for Horseraddish. You may need to buffer your soils with a lime agent etc.

Thank you for all of your responses. MA and KH, the soil that we grow the horseradish on is usually very high in organic matter. Usually any where from 25 to 56 percent organic matter. So the sulfur is usually very high, 120 pounds/acre. Calcium is 3000 to 5000 ppm. Boron is 1.2 to 2.5 ppm. The pH is usually on the high side, 7.0 to 7.5. The fields that we grow the horseradish on are in a rotation with wild rice. The horseradish is planted in the Fall and then harvested the Fall of the second year. The fields are then planted to wild rice and flooded with water from a river. Wild rice is grown for 2 to 3 years and then the fields are planted back into horseradish. So our rotation is 2 years horseradish, then 3 years of wild rice. The fields are then planted back into horseradish in the Fall of the 3rd year of wild rice. Normally our yields have been averaging 6 ton/acre and have been as high as 9 ton/acre. Now our yields are averaging 3 to 4 ton/acre and have been as low as 1 ton/acre. We harvest 300 acres of horesradish annually. Thank you for your input!

Michael - Thank you for your detailed answer. I have never seen specific numbers for horseradish. The numbers you gave for the nutrients, are they specific for horseradish? I knew of balancing P and K, but not the other nutrients that you mentioned. I did order your book "The Ideal Soil". I am anxiously awaiting the arrival of the book. It sounds like you have a lot of good stuff in your book!