Americas and Oceania Group - International Plant Nutrition Institute

Americas and Oceania Group
Mexico and Central America: Dr. Armando Tasistro
Global Maize Project in Mexico: Celaya, Guanajuato
Project Leader: Roberto Paredes, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP),
Colonia Roque Celaya, Guanajuato. E-mail: rparedesm59@prodigy.net.mx, paredes.roberto@inifap.gob.mx
Project Cooperator: Benjamin Zamudio
The study started in 2009 in Celaya, State of Guanajuato, Mexico, at 1,830 meters above sea level. The
treatment design included a combination of two management systems (plant populations) (Farmers’ practice
[FP] and a higher population [EI]) and three N fertilization regimes (0-N, 300 kg N/ha applied two out of
three years, and 300 kg N/ha applied every year). In 2011, the six treatments were: 1) 120,192 seeds/ha, 0-N;
2) 120,192 seeds/ha, 300 kg N/ha (0 N in 2009; 300 kg N/ha in 2010); 3) 120,192 seeds/ha, 300 kg N/ha (300
kg N/ha applied both in 2009 and 2010); 4) 90,580 seeds/ha, 0-N; 5) 2) 90,580 seeds/ha, 300 kg N/ha (0-N in
2009; 300 kg N/ha in 2010); 6) 90,580 seeds/ha, 300 kg N/ha (300 kg N/ha applied both in 2009 and 2010).
The first three treatments are considered as an intensification of the last three, which represent the traditional
farmers’ practice.
Yields responded to N, regardless of its application sequence. The application of 300 kg N/ha increased
grain yields from an average of 1.9 t/ha to 10.9 t/ha, a reflection of significantly greater Harvest Index, more
ears/ha, and larger ears with heavier kernels. Partial Factor Productivity and Agronomic Efficiency were 36
and 30 kg grain/kg N, respectively. No significant differences in grain yield could be detected between the
intensive and traditional management options, although plant population at harvest differed significantly
between them: 91,600 vs. 68,900 plants/ha, respectively. By harvest time, the plant population under both
management systems had decreased by 24% on average, which is higher than normal, especially under
experimental conditions. Most of that loss (15%) had taken place by the third week after crop planting.
IPNI-28
Global Maize Project in Mexico: Toluca, México
Project Leader: Benjamín Zamudio, González Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias
(INIFAP), Toluca, México. E-mail: zamudio.benjamin@inifap.gob.mx
The study was started in 2009 in Toluca, State of México, at an altitude of 2,370 meters above sea level.
The objective was to compare the effects of six combinations of plant populations and fertilizer applications.
Half of the treatments—labeled as intensive management—included high plant populations and the
application of a complete fertilizer formula (90 kg P 2 O 5 /ha, 90 kg K 2 O/ha, 44 kg MgO/ha, 50 kg S/ha, and
3 kg Zn/ha). The other half of the treatments were similar to current farmers’ practices with regards to plant
population and fertilizer application (30 kg P 2 O 5 /ha and 30 kg K 2 O/ha). Three N fertilizer application regimes
were combined with the management systems just described: 0-N, 300 kg N/ha applied two out of three
years, and 300 kg N/ha applied every year with the intensive management, and 0-N, 180 kg N/ha applied two
out of three years, and 180 kg N/ha applied every year, with the farmers’ management.
The 2011 season was very bad, with lack of rain at the beginning; followed by flooding, hail storms,
and a devastating early frost in the first week of September. The yield levels were therefore lower than in
the previous years. Yield under intensive management (3,594 kg/ha) was significantly higher than under
traditional management (2,699 kg/ha). This result mirrored the differences in plant population at harvest:
80,208 and 62,691 plants/ha in the intensive and farmers’ management treatments, respectively. Under
intensive management, yields with N (3,906 kg/ha) were 31% higher than without N (2,971 kg/ha), whereas
no significant effects from N could be detected under the traditional management. Partial Factor Productivity
IPNI Interpretive Summaries 43