U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
Date of this Version
March 1995
Abstract
Most corn planted in the United States is a single-cross hybrid; therefore the seed is produced on inbred lines. Inbreds are known to be less productive than the resultant hybrids; however, growers and seed companies want to maximize seed production. To this end growers attempt to keep mineral nutrition, especially nitrogen, non-limiting. Low production potential and high N fertilization rates can result in the likelihood of groundwater contamination. Key to proper N application is knowledge of the N response of inbred lines. The purpose of this research was to determine the yield and N uptake response of a group of representative inbred lines of corn to applied N, and to show that chlorophyll meter technology developed for hybrid corn is appropriate for inbreds in seed production fields. High levels of residual N, following a crop of soybean, resulted in no response to applied N. However, following inbred corn, yield, N uptake, kernel size, and salable seed (kernels passing a 26164-inch sieve but retained by a 16164-inch sieve) increased linearly with amount of applied N. Number of kernels per plant also increased as applied N increased. Inbreds varied greatly in their optimum N rate for both grain yield and salable seed yield. The average optimum N application rate for grain yield (77 lb N/ac) was about 10% greater than for yield of salable seed (70 lb N/ac). Data show that chlorophyll meter methodology developed to aid N management in hybrid corn functions equally well for N management in hybrid seed fields and its use should help seed producers optimize N use and reduce potential for groundwater contamination.
Comments
Published in Clean Water - Clean Environment - 21st century: Team Agriculture - Working to Protect Water Resources. Conference Proceedings, Volume 2: Nutrients. March 5–8, 1995. Kansas City, Missouri. American Society of Agricultural Engineers, 1995, pp. 243-246.