Even though precipitation was lower than normal early in the season for both years, the low yields in 2011 could be a consequence, not only of the low precipitation during the flowering period, but also the permanent precipitation deficit and the elevated temperatures throughout the season.

During the 2012 growing season, above-normal precipitation values were observed during the months of May and June, and maximum temperature was below normal for the months of June and July. These specific climatic conditions could favor pollination and grain filling.

According to the research, plant population has a strong effect on final yield, but the interaction between populations and the environment defines final yield.

As plant population increases, competition between plants for resources (light, water, and nutrients) increases.

The 2011 and 2012 growing seasons are good examples of the plant response to the environment, states the report.

During the 2011 growing season, a negative yield trend towards high population was observed with yield decreasing as plant populations increased, and that was independent of the planting date.

The precipitation deficit and the high temperatures observed in the 2011 season strongly affected the high plant population treatments (26,000 and 30,000) compared to the low population treatments (18,000 and 22,000).

Under the 2011 environmental conditions, the best corn production choice was the 22,000 plant population.

In 2011, changes in planting date had an overall impact on yield, but did not influence the yield response to plant population.

Corn planted on the April 12 (three and a half weeks later than the standard planting date) performed better than the standard planting date (March 17) which might be due to the rainfall and temperature observed during flowering.

Corn planted on March 17 received less precipitation during the period of flowering than the crop planted on the April 12.

There was also a sharp increase in maximum temperature after flowering of plants corresponding to the first planting date (March 17) compared to the second planting date which may have affected pollination and grain filling.

The increase in precipitation around mid‐July certainly favored ear development of the plants from the second planting date (April 12) which were harvested at the end of August, compared to the first planting date harvested in the first week of August.

In 2012, yield increased as plant populations increased, but reached a maximum at 26,000 seeds for both planting dates. The positive yield response to increases in planting density could be due to water availability from precipitation during the months of May, June and July.

Although there were yield differences between planting dates for all plant population treatments, the greatest difference was observed for the 26,000 plant population treatment.