Foliar Applications of Nutrients on Maize. I. Yield and N Content of Grain and Stover1
- F. E. Below,
- R. J. Lambert and
- R. H. Hageman2
Crop yield response to foliar fertilization has been variable, but few studies have utilized detailed plant analyses of field grown maize (Zea mays L.) hybrids known to differ in C and N metabolism and content to establish a role for foliar fertilization especially in plant and grain development. Field studies were conducted in 1981 and 1982 to determine whether foliar application of N would delay the remobilization of leaf N and leaf senescence thereby maintaining photosynthesis and increasing productivity. In 1981, N-P-K-S (12 kg N ha−1 per treatment) was applied to plants of five hybrids at 7 days before and 12 days after anthesis. In 1982, urea (two equal applications for a total of 67 kg N ha−1) was applied to three hybrids (B73 × Mo17, Pioneer brand 3382, and Farm Services brand 854) at 12 and 6 days before anthesis and 9 and 15, and 25 and 32 days after anthesis to give treatments 1, 2, and 3, respectively. Soil type was Drummer silt loam (fine-silty, mixed, mesic Typic Haplaquoll) in 1981 and a Flanigan silt loam (fine, montmorillonitic, mesic Aquic Arqiudoll) in 1982. In 1981, grain yield and N content, and the accumulation of dry weight and reduced N by the whole plant were unaffected by the spray treatments. In 1982, increases in whole plant N at physiological maturity in response to urea sprays were 0.1, 0.1, and 0.4 g N plant−1 for the 6rst spray, 0.5, 0.4, and 1.0 g N plant−1 for the second spray and 0.4, 0.5, and 0.5 g N plant−1 for the third spray for P3382, B73 × Mo17, and FS854, respectively. Grain yields of all hybrids were not affected by any treatment and significant increases in whole plant dry weight and grain yield of erect plants were noted only for FS854 (second treatment). Grain N of all hybrids was increased significantly by the thud treatment and for FS54 by the second treatment. Adverse effects of urea treatments were that stalk lodging was increased, and that the harvest indices for dry weight and N were not altered. Foliar application of N did not delay the remobilization of N from the leaves, and had little consistent effect on net photosynthesis or productivity. The use of foliar N sprays for increasing grain yield of maize grown at soil N levels commonly used for commercial production is not recommended.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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