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 nutrients other than N, P, and S, such as K, Mg, B, Cl^-, Cu, and Zn. Four sites were planted to wheat at Balcarce, Pieres, Tandil, and Tres Arroyos during the 2010/11 growing season.

Excellent climatic conditions during the 2010-11 growing season allowed high grain yields to be reached. Wheat check yields varied from 3,989 to 5,082 kg/ha, and NPS fertilized yields varied from 5,158 to 8,167 kg/ha. Responses were significant to NP at Balcarce (+2,797 kg/ha, +63%), Pieres (+1,492 kg/ha, +26%), and Tres Arroyos (+3,126 kg/ha, +61%); and to P at Tandil (+1,552 kg/ha, +43%). Grain yield responses were related to low soil nitrate-N, and 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 full season soybean during the fifth season of evaluation in 2011-12. Argentina-27