Long-term Nutrient Management Network for Southern Buenos Aires Province

In 2007-08, IPNI and Agroservicios Pampeanos (ASP) established a network of field experiments with the objectives of: 1) determining direct and residual responses to N, P and S, 2) evaluating recommendation methods for N, P and S fertilization, and 3) identifying the level of deficiency and potential responses to other nutrients such as K, Mg, B, Cl, Cu, and Zn. Four sites were planted to full season soybean at Olavarria, Pieres, Tandil, and Tres Arroyos sites during the 2011-12 growing season.

Soybean check yields varied from 1.2 to 3.3 t/ha, and NPS fertilized yields varied from 2.0 to 3.8 t/ha. Phosphorus responses were significant at Olavarria (+373 kg/ha, +13%) and Tres Arroyos (+320 kg/ha, +19%) sites, while P and S responses were significant at Tres Arroyos (+809 kg/ha, +69%) and Tandil (+363 kg/ha, +11%) sites. Grain yield responses related well to low Bray-1 P levels and good weather conditions. No responses were observed to nutrients other than N, P and S. These sites will be planted to barley during the sixth season of evaluation in 2012-13. Argentina-27.