Exploration of Responses to Potassium in Western Uruguay

Several regions of Uruguay has recently shown K deficiencies and responses. This project looks to determine the different areas with K deficiency, evaluate responses in the main field crops, and provide information on K soil testing.

IPNI-2007-URY-2

29 Apr 2016

2015 Annual Interpretive Summary


This research is based on previous observations of K deficiency and responses to K fertilization in field crops grown within the northwestern Uruguay region. Data from the first three years of field work and other studies, including 50 experiments under wheat, barley, maize, soybean, sunflower, and sorghum, indicated a critical K concentration of 0.30 to 0.40 cmol/kg (i.e., soil test K [STK] of 117 to 156 ppm). Below this K concentration, there is a high probability of a positive yield response to K fertilization. Integration of soil survey data with this field work has allowed researchers to estimate that an area of 4 million ha is potentially K deficient in Uruguay.

Field work in the 2014-15 growing season included field experiments evaluating K response in annual crops and pastures, and the continuation of the long-term experiment established on 2011. Responses in grain yield were observed at the long-term experiment, but not at the annual crops experiments.

Results of the project and K management strategies have been presented at several meetings organized by companies and farmer’s associations, and at the technical meeting organized by the No-Till Farmer‘s Association of Uruguay (AUSID). A peer-reviewed publication on delineation of management zones has been derived from the project and is published at http://www.fagro.edu.uy.