|Mosier, Arvin - U OF FLORIDA, GAINESVILLE|
Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 11, 2005
Publication Date: November 6, 2005
Citation: Halvorson, A.D., Mosier, A.R., Reule, C.A., Bausch, W.C. 2005. Nitrogen and tillage affects on irrigated continuous corn yields. American Society of Agronomy Abstracts. CD-ROM Publication. Technical Abstract: No-till (NT) irrigated production systems can potentially reduce soil erosion, fossil fuel consumption, and greenhouse gas emissions compared with a conventional till (CT) system. Tillage (CT and NT) and N fertilization effects on irrigated, continuous corn yields were evaluated for 5-yr on a clay loam soil to determine the viability of NT and N needs for optimum yield. Grain yields were significantly increased by N fertilization each year in both tillage systems, with a 16% higher yield in with CT than NT at maximum yield. Grain yields were near maximum with an available N (soil + fertilizer N) level of 276 and 268 kg N ha-1 with CT and NT, respectively. Nitrogen fertilizer use efficiency tended to decrease, but not always significantly, with increasing N rate in both systems, averaging 43% over N rates and years for both systems. Total N required to produce one Mg grain at maximum yield averaged 19 and 20 kg N Mg-1 grain in CT and NT systems, respectively. Corn residue returned to the soil increased with increasing N rate with no difference in residue production between tillage systems. The NT system had the same size plant for grain production as the CT system. Lower grain yield with NT probably resulted from slow early spring development and delayed tasseling compared to CT due to lower spring soil temperatures in NT. NT, irrigated, continuous corn production has potential for replacing CT systems in the central Great Plains area, but some type of reduced tillage, such as strip-tillage, may improve grain yields in the conservation tillage system. NT corn responded to available N supply similarly to CT corn. Current N fertilizer recommendations based on yield may need to be modified for NT to account for lower yield potential.