Nutrient Uptake of Maize Affected by Nitrogen and Potassium Fertility in a Humid Subtropical Environment

Nitrogen (N) and potassium (K) fertility management of maize (Zea mays L.) in the humid subtropical Mississippi Delta may differ from a temperate climate because of its use in rotation with cotton (Gossypium hirsutum L.), soil temperatures rarely falling to 08C, and heavy winter rains that facilitate nutrient losses. An experiment to determine the [N] (concentration 1⁄4 [ ]), phosphorus [P], [K], calcium [Ca], magnesium [Mg], iron [Fe], manganese [Mn], zinc [Zn], and copper [Cu] and their total contents plant of maize grown in rotation with cotton, using N fertility levels of (134, 179, 224, 269, and 314 kg N ha) in combination with K fertility levels of (0, 45, 90, and 134 kg K ha) was conducted in 2000 and 2001 at Tribbett, MS. Ear leaves, immature ears, and husks collected at growth stage R2 and grain and stover collected 21 days after R6 were dried, weighed, and analyzed for nutrient concentration. Plots were also harvested for yield, kernel weight, grain bulk density, and harvest index (HI). Increased [N] values of about 1.3 mg g occurred in all organs except the stover between 134 and 314 kg N ha N fertility. Stover [N] increased approximately 3.0 mg g within the same N fertility range. Total N content of ear leaves, grain, and stover increased by about 11.0, 550.0, and 730.0 mg plant, respectively, with N fertility increased from 134 to 314 kg N ha. Yields, kernel weights, grain bulk densities, and harvest indices also increased with added N fertility. Several micronutrient concentrations and contents increased as N fertility increased. Received 8 August 2004, Accepted 10 May 2005 Address correspondence to H. Arnold Bruns, USDA-ARS, Crop Genetics and Production Research Unit, Box 345, Stoneville, MS 38776, USA. E-mail: abruns@ars. usda.gov Communications in Soil Science and Plant Analysis, 37: 275–293, 2006 Copyright # Taylor & Francis Group, LLC ISSN 0010-3624 print/1532-2416 online DOI: 10.1080/00103620500408829