Nitrogen Fertilizer Management and Recommendations for Wheat Production in Central Mexico
- Agustin Limon-Ortega * and
- Eduardo Villaseñor-Mira
The current N fertilizer recommendation for wheat (Triticum aestivum L.) production in the central highlands of Mexico is to apply 71 lb N per acre. However, this N rate appears to exceed current crop needs. Therefore, research activities in farmers’ fields to estimate the optimum N rate and timing were initiated in 1999 and continued until 2002. A field trial was conducted at eleven location-years representing the major wheat production areas of central Mexico. Four N rates were applied (0, 36, 63, and 89 lb N per acre) under three N timing strategies; basal at planting, end of tillering-early jointing, between 30 and 60 days after planting, and split (one third at planting and the remaining two thirds at the end of tillering-early jointing). To estimate the critical N fertilization rates for optimum grain yield in each environment, yield data was fitted to a linear plateau model on N fertilization rates. Results indicated that the critical N rate for optimum wheat production is lower than current N fertilizer recommendation. According to the regression model used, predicted critical N fertilization, that explained 47% of the optimum grain yield variability, ranges from 28 to 66 lb N per acre. For grain yield goals below 45 bu/acre (± 3.1 bu/acre), farmers do not have to apply N fertilizer. For grain yield goals above this threshold, farmers have to apply 2.6 lb N per acre for every additional bushel expected. Nitrogen fertilizer application at the end of tillering-early jointing (Feekes scale 6) showed a tendency to increase grain yield by means of increasing the number of spikes per unit area.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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