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Contribution of organic phosphorus in predicting soybean response to phosphorus fertilization


The use of organic P fraction in soil test P for soybean under no-till could improve the accuracy to predict the response of crops to P fertilization. Bray P is the most commonly used soil test in the Pampas Region of Argentina. However, previous local reports showed small or no soybean yield response to P fertilization in sites with Bray P below critical levels. This lack of fertilizer response could be due to P supply from organic fractions not taken into account by Bray P.

A recent article published in the Soil Science Society of America Journal assessed the contribution of P indices including organic-P fractions in predicting soybean response to P fertilization compared with Bray P. The study included an on-farm network of P fertilization experiments conducted in the Pampas Region of Argentina.

soil samples in jars

Relative soybean yield correlated with bioavailable and mineral-associated soil phosphorus. Bioavailable P did not enhance soil test P performance compared with Bray P. However mineral-associated P fraction improved the accuracy of predicting soybean yield response to P fertilization.

Studies in progress seek to increase the accuracy of soil test P for no-till soybean crops to develop better P fertilization practices and optimize P fertilizer efficiency.

Read the full article in SSSAJ. Free preview Jan 11 - Jan 18