Always read and follow label directions.
Jonathan and Patrick’s Crop Report
The Cropwalker newsletter is a venture between Jonathan Zettler and Patrick Lynch. We have chosen not to have sponsors or advertisers. We believe that readers want information that is factual, informative, timely and easy to read. That is why we will be running this as membership-based newsletter. Currently it is free and will be for another two weeks. Going forward we will publish one free issue a month for our subscribers, with the other issues available only to our members.
You can sign up to become a member at:
1. Reminders of certain repetitive topics such as seeding depth, yield loss with delayed planting or replants, how to tell when frost kills a plant
2. Latest in season thoughts on fungicide timings, products for certain diseases, tank mixes
3. Suggest which product from main line companies control which weeds, such as lambs’ quarters in IP beans, dandelion, volunteer corn, etc…
4. Reminders of safe fertilizer rates in starters, and broadcast
5. Comparison of relevant in season products such as sulphur sources for wheat
6. Attempt to stay current on in-season crop issues such as aphids, leafhoppers, and western bean cutworm
We will focus articles on the main field crops; corn, soybeans, forages and winter wheat.
What Rates of Phosphorous and Potassium is Needed to Change Soil Test Levels
It takes about 25-50 lbs./ac of P2O5 to move a soil test one point. The higher numbers are for heavier soils such as Brookston clays and lower are for silt loam soils. Thus, if a soil test drops 5 points it is equivalent to removing 150 – 250 lbs./ac P2O5 (290 – 480 lbs./ac MAP) without replacing any P2O5. A 3-crop rotation of 200 bushels corn, 60 bushels of soybeans, and 100 bushels wheat would remove about 240 lbs./ac P2O5. It takes about 8-12 lbs./ac of K20 (13 – 20 lbs./ac Red Potash) to move the soil test level one point. The same crops remove about 340 lbs./ac K20.
4R Nutrient Management
I was recently asked what the 4Rs stand for, here they are in summary. The comments are my own opinion in layman’s terms.
1. Right Place – it is placed where it will get a response
2. Right Time – it is at a time the plant will respond to it
3. Right Source – it is a source that has high likelihood of response, compared to the alternatives
4. Right Rate – it is a rate that is appropriate for crop response/long term fertility objectives
Reducing Phosphorus Movement
Based upon my readings and meetings attended, it comes down to 1 thing. Phosphorus must come into contact with soil. A few of the studies involved tillage to get soil contact, but that doesn’t have to be the case. The issue with no-till acres is that the top layer of the soil becomes supersaturated with phosphorus over time, and is unable to hold additional phosphorus when broadcast on the soil surface. If you want to practice 4-R nutrient management in a no-till or limited tillage system, it is imperative to have the ability to band phosphorus, both for crop response and to limit off-site movement.
Every field is different in some respects, but they all have a few limiting factors that you can’t manage your way out of. So the question is what are those factors on your fields? Will share more thoughts in the next issue.
Stop researching every aspect of it and reading all about it and debating the pros and cons of it … Start doing it. -