OFA AGM
The Manitoulin North Shore Federation of Agriculture Annual Meeting and Dinner will be held on October 3 at 6:30 pm at the Mindemoya Community Centre. This is a new location this year. For additional details please contact Mack Emiry.
Deciphering fertilizer recommendations
Why is it that you sometimes receive different fertilizer recommendations from the same soil test results? Agronomists and farmers may use different assumptions and objectives when determining how much fertilizer and manure to apply. The main approaches for determining fertilizer application rates from a soil test result include: 1. Sufficiency; and 2. Build-up (or draw-down) and maintenance. Sufficiency Approach: The sufficiency approach rate is the most economic during the year of application. The value of the yield response is expected to pay for the cost of the fertilizer within that year. The sufficiency approach is designed to minimize the cost of fertilizer relative to yield within a given year. It requires frequent soil testing and annual fertilization, unless the soil test is high. It is most suitable for short-term decisions, including annual land rental agreements or limited cash flow. It is associated with a low risk of over-fertilization. Recommendations in OMAFRA Publication 75, Agronomy Guide, use the sufficiency approach. Build-up and Maintenance: Sometimes also known as “target and maintenance” it is a longer-term approach that targets an ideal soil test value to meet the crop needs. Then over time, “builds-up” or “draws-down” the soil test to this level and then maintains it. 1. For build-up of a low testing soil to target level, the rate is calculated by determining and adding: The crop removal amount estimated from the expected yield, and the additional fertilizer needed to increase the soil test to the target level over time. 2. Once in the target range, the soil test level is maintained by applying the amount removed by the crop. 3. Above the target level, no fertilizer is applied, allowing soil level to draw down to the target range. Suggested target soil tests levels are 15 ppm P and 125 ppm K. Within ranges (12 – 18 ppm P, 100 – 150 ppm K) the recommended fertilizer rate for maintenance would be the same as crop removal. For suggested crop removal rates, refer to Table 9-14, Publication 811, Agronomy Guide.
