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Red clover, alsike clover & birdsfoot trefoil fertilizer recommendations
These legume crops, if properly inoculated, can take enough nitrogen from the atmosphere that they won't need fertilizer N after the crop is established. A small amount (less than 25 lb. N/ acre) may aid in getting successful establishment on sandy soils. Crops won't need fertilizer N for establishment on soils that are not sandy.
Table 1 summarizes the phosphate suggestions for these crops. The potash guidelines are in Table 2. You can topdress phosphate and/or potash fertilizers on established stands annually. The suggested rates of these two nutrients can also be broadcast and incorporated before seeding. This management practice may help in achieving a satisfactory stand.
In table 1 use one of the following equations if you want a phosphate guideline for a specific soil test and a specific expected yield:
- Recommended P2O5 = [20 - (1.0) (Bray P in ppm)] (Expected yield)
- Recommended P2O5 = [20 - (1.4) (Olsen P in ppm)] (Expected yield)
Table 1: Phosphate fertilizer guidelines
| Expected yield | P soil test: 0-5 parts per million (ppm) Bray and 0-3 ppm Olsen | P soil test: 6-10 ppm Bray and 4-7 ppm Olsen | P soil test: 11-15 ppm Bray and 8-11 ppm Olsen | P soil test: 16-20 ppm Bray and 12-15 ppm Olsen | P soil test: 21+ ppm Bray and 16+ ppm Olsen |
|---|---|---|---|---|---|
| 2 tons per acre | 35 lbs. of P2O5 per acre | 25 lbs. of P2O5 per acre | 15 lbs. of P2O5 per acre | 0 lbs. of P2O5 per acre | 0 lbs. of P2O5 per acre |
| 3 tons per acre | 55 lbs. of P2O5 per acre | 40 lbs. of P2O5 per acre | 25 lbs. of P2O5 per acre | 10 lbs. of P2O5 per acre | 0 lbs. of P2O5 per acre |
| 4 tons per acre | 70 lbs. of P2O5 per acre | 50 lbs. of P2O5 per acre | 30 lbs. of P2O5 per acre | 10 lbs. of P2O5 per acre | 0 lbs. of P2O5 per acre |
| 5 tons per acre | 90 lbs. of P2O5 per acre | 65 lbs. of P2O5 per acre | 40 lbs. of P2O5 per acre | 15 lbs. of P2O5 per acre | 0 lbs. of P2O5 per acre |
Table 2 summarizes potash recommendations for red clover, alsike clover and birdsfoot trefoil. Use the following equation if you want a potash guideline for a specific soil test and a specific expected yield:
Recommended K2O = [53.28 - (0.333) (Soil test K in ppm)] (Expected yield)
Table 2: Potash fertilizer guidelines
| Expected yield | K soil test: 0-40 ppm | K soil test: 41-80 ppm | K soil test: 81-120 ppm | K soil test: 121-160 ppm | K soil test: 161+ ppm |
|---|---|---|---|---|---|
| 2 tons per acre | 95 lbs. of K2O per acre | 65 lbs. of K2O per acre | 40 lbs. of K2O per acre | 15 lbs. of K2O per acre | 0 lbs. of K2O per acre |
| 3 tons per acre | 140 lbs. of K2O per acre | 100 lbs. of K2O per acre | 60 lbs. of K2O per acre | 20 lbs. of K2O per acre | 0 lbs. of K2O per acre |
| 4 tons per acre | 185 lbs. of K2O per acre | 135 lbs. of K2O per acre | 80 lbs. of K2O per acre | 25 lbs. of K2O per acre | 0 lbs. of K2O per acre |
| 5 tons per acre | 230 lbs. of K2O per acre | 165 lbs. of K2O per acre | 100 lbs. of K2O per acre | 35 lbs. of K2O per acre | 0 lbs. of K2O per acre |
Other nutrients
These legumes will respond to the application of lime if the soil pH is less than 6.0. Lime suggestions for these crops have not been well defined. We suggest an application of 3,000 lb. ENP per acre for crops grown on acid soils. The lime should be broadcast and incorporated before seeding.
Except for the need for sulfur (S) when these crops are grown on sandy soils, other nutrients are not needed in a fertilizer program. Use an annual broadcast application of 25 lb. S per acre when these crops are grown on sandy soils.
Reviewed in 2018