Nitrogen Fertilizer Management and Recommendations for Wheat Production in Central Mexico

Abstract

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.

Rainfall as a Limiting Factor for Wheat Grain Yield in Permanent Raised‐Beds

“…Therefore, a fine‐tuning of N to overcome the effects of the stabilization period is not much an issue for an average of 2360 kg ha −1 wheat crop. Actually, other reports have indicated that N fertilizer for rainfed environments with a grain yield potential of 3000 kg ha −1 or less, N fertilizer may not be needed as grain yield increase is minor (Limon‐Ortega and Villasenor‐Mir, 2006).…”

Agronomic and physiological aspects of nitrogen use efficiency in conventional and organic cereal-based production systems

“…Critical periods of N demand vary in crops and adjusting fertilization timing according to crop N requirements may reduce the risk of N loss and excessive N fertilizer application (Fageria and Baligar, 2005). For instance, the critical timing of N demand in spring wheat is between double ridge to terminal spikelet phases (between 20 and 45 days after seeding) (Limon-Ortega and Villaseñor-Mir, 2006), while in maize it ranges from 35 to 45 days after seeding (Richie et al, 1986). In malting barley, adjusting the amount of split-N application is necessary to ensure good malting quality (Baethgen et al, 1995).…”

Soil Erosion Issues in Agriculture

“…According to Schillinger (2005), the number of heads is generally the most important yield component and is primarily affected by management practices such as seeding rates and N inputs (Zhang et al, 2007). One way to optimize tillering and yield component formation is through the timing of N application (Weisz et al, 2001;Limon-Ortega & Villaseñor-Mir, 2006). A regression analysis with grain yield suggests that attaining 350 heads/m 2 is key to achieving about 3500 kg/ha of wheat in the Mexican Plateau (Limon_ortega, 2011).…”