The fertility requirements of Bedford silt loam
1934
Walker, G.P.
Liming has proved an important factor in raising yields of all crops to paying levels in 16 years of field plat tests on Bedford silt loam. After liming, phosphorus was indicated as the principal plant food need of this soil for a number of years. Without manure or potash its effect is dropping rapidly in recent years. Nitrogen in spring and fall was effective on wheat. Increasing the spring application from 6 to 15 pounds per acre has produced a 5-bushel increase per acre. Potash in addition to phosphate showed little or no effects on wheat, soybeans, or clover. It was ineffective on corn in earlier years but has become increasingly important during the past 10 years where no manure has been used. Manure has produced fair increases on corn and only small increases on the other crops in the rotation unless supplemented by phosphate. A system of returning the manure produced, supplemented by 700 pounds of commercial fertilizer in the 4-year rotation on limed land has maintained yield levels of 31 bushels of corn, 9.5 bushels of soybeans, 14 bushels of wheat, and about a ton of clover hay per acre above the production levels of untreated Bedford silt loam over a 16-year period.
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