Interpretive Summaries:

Five experimental sites were planted to wheat/soybeans (full rotation: corn-wheat/soybeans), and six sites to full season soybeans (full rotation: corn-soybeans-wheat/soybeans). In wheat, significant responses to N were found at two sites, and to P at four sites. Nitrogen responses were related to low soil nitrate-N availability at planting (less than 60 kg/ha nitrate-N at 0 to 60 cm) and P responses were related to low Bray P-1 test levels (less than 15 mg/kg). For double cropped soybeans, one site showed significant responses to P and three sites responded to S. Sulfur responsive sites had soil sulfate-S lower than 10 mg/kg at planting. In full season soybeans, only one of the six sites showed significant responses to PS fertilization. In 2002/03, the experiments will either be planted to corn or to wheat/soybeans.

Farmers in the CREA groups of southern Santa Fe grow approximately 185,000 ha of annual crops within an agricultural area of approximately 600,000 ha where they are leading farmers. ARGENTINA-12