Defoliation and Fertilizer Nitrogen Effects on Nitrate-nitrogen Profiles in Maize1
- D. R. Hicks and
- R. H. Peterson2
Corn (Zea mays L.) vegetative tissue remaining after hail damage is often utilized for forage. Environmental stresses may cause levels of nitrate-nitrogen (NO−3-N) in plant tissue that are toxic to ruminants. This study was conducted to determine the effect of leaf blade removal (simulated hail damage) and N fertilization of the soil on the NO−3-N profile of corn fodder.
Leaf blade removal of 0, 50, 100% was imposed at tasseling on the corn hybrid ‘Dekalb XL45A’ grown in soil fertilized with either 115 or 230 kg N/ha. Plants were sampled approximately weekly for 6 weeks after defoliation.
Both stalk and total fodder NO−3-N concentration increased as either level of defoliation or N rate increased. Stalks of nondefoliated plants contained up to over 4,500 ppm (dry matter basis) NO−3-N while stalks of plants having 50 and 100% of the leaf blades removed contained up to 5,000 and 5,500 ppm NO−3-N, respectively.
When completely defoliated, fodder NO−3-N concentration was as high as 1,900 ppm for corn receiving 115 kg N/ha. Fodder of 100%-defoliated plants receiving 230 kg N/ha contained as much as 2,300 ppm NO−3-N.
These results suggest that corn fodder NO−3-N concentration increases due to the defoliation caused by hail. Thus hail damage to corn fodder may increase the chances of NO−3-N toxicity to animals, especially when high rates of fertilizer N are used.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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