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Show Nitrogen plus phosphorus sustains grass Grass will use large amounts of nitrogen, but it also requires some phosphorus to sustain growth. A balance of phosphorus phosphor-us must be present in the soil if the grass is to fully utilize the nitrogen that has been applied. ap-plied. Clover and alfalfa (legume (le-gume plants) are heavy feeders feed-ers of phosphorus, but they fix their own nitrogen from the air. Applying phosphorus to a grass legume pasture or hay field serves a dual purpose. It provides the phosphorus re- uii emtiiua ui. uoui Liie grass and legumes and by stimulating the legume growth, these plans fix more nitrogen from the air and make it available in the soil for the grass to use. On the Ivan Kerbel ranch, a series of fertilizer field plots were installed on a grass legume le-gume hay field (90 gross, timothy, smoothbrome, orchard, and 10 legumes, red clover, and alsike clover). One plot had only nitrogen applied, 80 pounds of nitrogen per acre, and the remainder of the plots had various rates of nitrogen and phosphate applied in several sev-eral combinations. Where no fertilzer was applied, the yield was .97 tons per acre. With hay valued at $22.00 per ton, his gross return per acre would be $21.34. An application of 80 pounds of nitrogen per acre increased the yield to 3.39 tons. The hay value would be worth $74.58. After subtracting the cost of the fertilizer, $9.60, the farmer's return has increased to $64.98 per acre. By applying the same amount of nitrogen, with 40 pounds of phosphorus, the yield was increased another one and a half tons above the plot where only nitrogen was applied. |