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WW-00792 Revised 1993
| Table 1. The effect of banded and broadcast phosphate on corn yield when soil test levels for P are low. |
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| Phosphate Applied lb P2O5/acre |
Placement | Yield bu./acre |
| 0 | - | 122 |
| 40 | starter | 146 |
| 100 | broadcast | 148 |
| Soil test P (Bray and Kurtz #1) = 6 ppm; study conducted at the Southwest Experiment Station, Lamberton |
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| Table 2. Soybean yields as affected by the rate of phosphate applied (1986-1988 ave.) |
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| Location | ||
| Phosphate Applied | Waseca | Lamberton |
| lb./acre | - - - - - bu./acre - - - - - | |
| 0 | 31 | 27 |
| 23 | 33 | 29 |
| 46 | 35 | 30 |
| 69 | 36 | 30 |
| 92 | 37 | 32 |
| Soil Test P (ppm): | 5 | 3.5 |
| (Bray and Kurtz #1) | ||
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| Table 3. Interpretation of plant analysis values for phosphorus. | |||||
| Crop | Plant part and sampling stage | deficient | low | sufficient | high |
|---|---|---|---|---|---|
| - - - - - - - - - % P- - - - - - - - - | |||||
| corn | whole plant; 12 in. height | - | - | .40 | > .80 |
| ear leaf at tasseling | < .16 | .16 | .25 | > .50 | |
| small grain | Top leaves, boot stage | < .16 | .16 | .21 | > .50 |
| alfalfa | upper 1/3 of plant, early bloom | < .16 | .16 | .25 | > .70 |
| sunflowers | 5th leaf at flowering | < .15 | .15 | .30 | > .50 |
| Adapted from Soil Testing and Plant Analysis, Soil Science Society of America (1973). Values subject to modification as research develops. | |||||
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