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. Three sites (Pieres, Tandil and Tres Arroyos) were planted to barley during the 2012-13 growing season.

Barley yields from unfertilized plots varied from 1.7 to 3.2 t/ha, and yields from NPS-fertilized treatments varied from 2.3 to 4.0 t/ha. A positive yield response to P was significant at the Tandil site (+434 kg/ha, +23%) and NPS response was significant at Pieres (+885 kg/ha, +28%). No responses were observed to nutrients other than N, P and S. No responses to applied fertilizers were observed at the Tres Arroyos site. Grain yield responses at Tandil and Pieres related well to low Bray-1 P concentrations and good weather conditions during the growing season. In these first 6 years of evaluation, which included soybean and barley crops, the NPS treatment outperformed the check treatment in increasing barley yields by 3.4 t/ha (+23%). These sites will be planted to soybean during the seventh season of evaluation in 2013-14.