Site Specific Nutrient Management for Soft Corn Varieties in the Highlands of Guatemala


08 Feb 2010

2009 Annual Interpretive Summary

Five experimental sites were established at Alta Verapaz to initiate a site-specific management project in farm fields within the highlands of Guatemala. A simple experiment was designed to compare a balanced treatment based on local experience against plots with individual omission of N and P. All experimental plots were planted with a population of 62,000 plants/ha arranged in rows 0.8 m apart and hills 0.4 m apart. Every hill received two seeds. This is a major change in crop management introduced in the experiment to ensure a uniform population. Farmers normally plant 40,000 seeds with 4 to 5 seeds in each hill, which are unevenly distributed in the field. Competition within the hills leads to only one or two plants producing a good corn ear and this reduces yield potential. The exploratory balanced treatment was 146-90-74 kg N-P2O5-K2O/ha + 26 kg MgO, 43 kg S, 1.1 kg Zn, and 2.4 kg B/ha. Results will determine attainable yield under this new crop and nutrition management and will be used to calculate rates needed to achieve a yield target for 2010.

Grain yield from the five sites ranged from 4.5 to 3.1 t/ha for the complete treatment, from 4.2 to 2.0 t/ha the P omission plot, and from 2.6 to 1.2 t/ha for the N omission plots. The high yield of 4.5 t/ha is a reasonable estimate of attainable yield for the soil and climatic conditions prevalent in Alta Verapaz and has becomes the target yield for 2010. This is an important improvement over yields normally obtained by the local farmers. A new rate of fertilizers will be calculated at each site which will be tested in 2010 besides a new set of omission plots.

This process will progressively fine-tune the fertilizer rates for the recommendation domain at Alta Verapaz. Improved crop and fertilizer management can lead to higher attainable yields, higher nutrient use efficiency, and a better economy for the local farmers. Guatemala-06