Establishing a Plant Nutrition Network for the CREA Region in Southern Santa Fé

On-farm field experiments establish as a long-term network in 2000, to evaluate responses to N, P, and S in wheat, soybean, and maize in the southern Santa Fe and Southeastern Cordoba regions. Evolution of soil properties are evaluated periodically in teh different treatments.


29 Apr 2016

2015 Annual Interpretive Summary

The Regional Consortium of Agricultural Experimentation (CREA), a farmers' organization based in Southern Santa Fe, has established a network of field experiments with the objectives of: 1) determining direct and residual responses to N, P, S, and where indicated, to K, Mg, B, Cu, and Zn), 2) evaluating recommendation methods for N, P and S fertilization, 3) identifying the degree of deficiency and potential response to nutrients other than N, P and S, and 4) evaluating the evolution of soil quality under contrasting nutrient management practices. In 2014/15, the two sites under corn-wheat/soybean (C-W/S) rotation were planted to corn, and the three sites under corn-soybean-wheat/soybean (C-S-W/S) rotation were planted to wheat/soybean.

Adequate climatic conditions across the five sites resulted in high grain yields in all three crops. Corn grain yield responses were significant to NS and to P at Balducchi, and to NPS at San Alfredo. Responses to NPS averaged 5.6 t/ha (+75%) for both sites. Wheat grain yield responses were significant to applications of N and P at La Hansa and to N, P, and S at La Blanca and Lambare. Average grain yield response to NPS at the three sites was 2,290 kg/ha (+86%). Response to other nutrients (K, Mg, B, Cu, and Zn) was significant only at Lambare. Double-cropped soybean, planted after wheat, reached record yields and showed significant responses to NPS, an average yield response of 1,545 kg/ha (+49%). Responses to N were related to available N at planting (soil + fertilizer N) for corn and wheat. Corn yields of 10 to 12 t/ha might be reached with 144 to 271 kg N/ha; while wheat yields of 4 t/ha would be reached with 140 kg N/ha. Significant relationships were observed between Bray P-1 soil P concentrations and P responses, with critical P concentrations ranging between 11 and 19 ppm Bray P-1 for the three crops. Below these critical levels, P responses are highly probable. Responses to S were related to pre-plant soil sulfate-S test (0-20 cm), with a critical level of 10 ppm for corn and double-cropped soybean.

For the 2015/16, sites will be cropped to wheat/double cropped soybean under the C-W/S rotation, and to corn under the C-S-W/S rotation.