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Show Find Phosphorus Test Worth While Reveals Great Variation in the Makeup of Soils to Grow Legumes. By C. M. LInsley, Soils Extension Specialist, University of Illinois. WNU Servlco. Vast changes now being made In cropping systems on farms will be less risky If farmers test their soils for available phosphorus, as well as for limestone, before seeding legumes and other crops. Tests made on thousands of acres of farm land throughout the state have shown that soils vary tremendously In their available phosphorus content, as well as in acidity. Consequently, there is a great variation In the ability abil-ity of soils to produce legumes, since these crops have definite phosphorus requirements as well as certain lime needs. It has been estimated that some 1,800,000 acres of Illinois land is being be-ing taken out of grain production and that a large proportion of this acreage acre-age Is being seeded to legumes. The only sound basis for making such adjustments ad-justments Is to use the phosphorus test along with the soil acidity test. These two tests together will show : (1) what legume is best adapted to a given piece of land ; (2) what land might be best suited to grow a certain kind of legume, and (3) whether any phosphorus or limestone need be applied ap-plied for the successful growing of legumes. The test described was developed four years ago by the experiment station sta-tion of the agricultural college, and it is coming into new prominence now because of the widespread shifts In production. All that is required for making the test is the phosphorus testing solution and a tin rod, together with a set of vials with corks and a rack to hold them. A small sample of the soil is shaken up in a vial of the solution, and if the soil is low in available phosphorus, phos-phorus, the solution remains uncolored. As the phosphorus content of the soil increases, the color of the solution changes to blue of different shades, depending upon the amount of phosphorus phos-phorus present. |
