Show GRAIN SOYBEANS DEPLETE THE SOIL but if plowed under they increase soil nitrogen by PROF GEORGE D suit soil chemist Cb emitt al ex station purdue uni many farmers do not realize that soybeans harvested for grain are a soil exhausting rather than a soil building crop if soybeans are plowed under or cut for hay and the manure is returned to the soil they do increase the soil nitrogen and thus increase the corn or wheat yields that follow in the rotation but harvested for commercial purposes such as oils plastics etc they represent a drain on the soil A crop of 20 bushels of soybeans harvested for commercial purposes removes 15 pounds of phosphate equivalent to 75 pounds of 20 per cent super phosphate and 20 pounds of potash per acre soybeans are certain to play an increasingly important part in the present war effort at present very little information hasteen has been obtained on how to provide a profitable means of directly fertilizing soybeans at the time of seeding but experiments peri ments now in progress at purdue university involving plowing under phosphate and potash indicate that effective means are being found with a favorable price outlook a greater acreage will be planted to soybeans this year farmers will find it advantageous to fertilize the crop unless their soils have been adequately treated previously in the rotation based on experience at the university the following suggestions may be of value if the soil is acid lime it adequately this winter this is important for otherwise the fertilizer will be lost in many cases about three tons per acre will be effective then just before plowing the ground for soybeans broadcast about pounds of 0 20 20 or pounds of 0 12 12 and plow under do not use any fertilizer when planting the beans the benefits from the lime will last at least 10 years although it has been found prof profitable bitable to in about six years indicative of the importance of plowing down fertilizer for soybeans was a test at the purdue experiment peri ment station last year on an unfertilized plot the soybean yield was bushels of grain or pounds of hay an acre when an equivalent of 1000 pounds of 4 10 25 had been broadcast and disked into the topsoil immediately before seeding the yield increased only 19 bushels but when this same amount was broadcast and plowed under the yield per acre was bushels of grain or pounds of hay when lime at the rate of three tons per acre was used with the fertilizer and plowed under the yield was bushels of grain or pounds of hay per acre |