Show L Soil Needs Nitrogen I How lime clover and crop residues residues residues resi resi- dues increase the soils soil's nitrogen and organic matter supply and thus boost crop yields is shown by the chart below This drawing summarizes summarizes summarizes izes results of tests at the Dixon soil experiment field by University of Illinois agronomists All three plots in the tests were limed and the crop rotation on each included corn oats and wheat One plot had no clover The small grain straw was removed and the cornstalks were burned This plot produced a year four-year average of 57 bushels per acre The second plot had the same NO UMENO CLOVER CORNSTALKS BURNED coN COON 57 57 ST BU Bli UME UME ET CLOVER CLevER CORNSTALKS TAU 5 BURNED cow COON 81 8 BU AJ LIME SWEET LIME CLOVER OAT COT AND WHEAT STRAW PLOWED UNDER CORN CORN- 88 BU BIJ m m treatment except that sweet clover was seeded in th the nd under as a r g-r green manure crop for orn The increased nitrogen and organic matter from the clover boosted the corn yield 24 bushels On the he third plot sweet clover was grown and in addition the cornstalks cornstalks corn corn- stalks talks oats straw and wheat straw were returned to the soil The extra matter nitrogen and other plant foods thus saved and returned in the crop residues gave the soil what it takes to yield 88 bushels of Df f corn per acre |