Global Maize Project in Mexico: Toluca, México

The corn producing areas of tropical Latin America provide a diverse set of climatic conditions that result in a wide range of yield potentials and consequently nutrient requirements. In tropical areas, latitude and altitude have a profound effect on yield. For these reasons, it is necessary to determine yield potential and attainable yield under the best known management practices. It is also necessary to quantify the effect of such management on nutrient use efficiency, particularly N. The study was conducted at Tolcula, Mexico State, at an altitude of 2,370 meters above sea level. The experiment will be in the field for at least 10 years. Treatments in 2009 were: 1) best crop management including all needed nutrients and optimal plant population (with amounts adjusted each year according to past results achieved); 2) farm practice including all changes made by farmers during the study period; 3) treatment 1 without N application; and 4) treatment 1 with N application in 2 of 3 consecutive years.

Although drought affected this site, best crop management + N and 90,000 plants/ha produced the highest yield of 7.6 t/ha, while the same plant density under best crop management - N produced 5.2 t/ha. Farmer practice + N and 70,000 plants/ha produced 7.0 t/ha, while the same plant density under farm practice - N produced 4.8 t/ha. The yield potential using the “Hybrid-Maize” model and NASA weather data was 13.7 t/ha. IPNI-29