Effect of Nitrogen Source on Corn and Bromegrass Production, Soil pH, and Inorganic Soil Nitrogen
1972
Power, J. F. | Alessi, J. | Reichman, G. A. | Grunes, D. L.
Little information is presently available on the effects of N source on dryland crop production in the Northern Plains. Therefore a field experiment was conducted for 4 years to assess the relative merits of ammonium sulfate, ammonium nitrate, calcium nitrate, and urea applied annually at 55 and 110 kg N/ha to both corn (Zea mays, L.) and bromegrass (Bromus inermis, L.) grown on a fine sandy loam (pachic haploboroll) with surface pH of 6.5 and no free carbonates. Plants were harvested at maturity and soils were periodically sampled for water content, inorganic N content, and pH. Corn production was highest for ammonium sulfate and ammonium nitrate at 110 kg N/ha. Leaf tissue at silking from all fertilized corn contained over 2.8% total N. Soil inorganic N accumulating during the first 3 years under corn was leached below the root zone by 514 mm of precipitation during the fourth growing season. At the 110-kg N rate, bromegrass production was lowest with urea, possibly because of ammonia volatilization. Nitrate sources of N greatly enhanced early season growth of bromegrass. All fertilizer N applied was immobilized in the bromegrass ecosystem, prohibiting any carryover or leaching of soil nitrate. Soil pH changes due to fertilization were not reflected in plant growth.
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