| Autor: |
Wedin, W. F., Vetter, R. L., Scholl, J. M., Woods, W. R. |
| Zdroj: |
Agronomy Journal; November 1967, Vol. 59 Issue: 6 p525-528, 4p |
| Abstrakt: |
In southern Iowa, pastures renovated with birdsfoot trefoil but containing white clover were compared over an 8‐year period (1956–1963) with unimproved pastures and also with Kentucky bluegrass—white clover pastures fertilized with nitrogen (N) and phosphorus (P) (fertilized grass). A 2.7‐fold increase in beef produced per hectare resulted for pastures renovated with birdsfoot trefoil over unimproved pastures. A 1.7‐fold increase was obtained for fertilized grass over the unimproved. Average daily grain for yearling steers was significantly greater at 0.76 kg/day for pastures renovated with birdsfoot trefoil, as were grazing days and beef production (423 kg/ha) (P < 0.01) over fertilized grass. In addition, growth and grazing of birdsfoot trefoil pastures were more favorably distributed over the season. Considering renovation of pastures vs. N purchased annually for grass pastures, renovation with birdsfoot trefoil is strongly favored. Unimproved pastures require little expenditure but do not produce cheap forage if cost of land, fencing, etc., are considered. The extensive use of permanent pastures should be rejected because each site amenable to improvement may eventually need to be used at the level where all controllable inputs are maximized. Although pastures renovated with birdsfoot trefoil were superior to fertilized grass pastures, the decline in contribution by the legume in renovated pastures suggests need for research at higher levels of fertility and management than those used in these studies. |
| Databáze: |
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