Deliverables/Results:

• Residual effects of previous fertilizations were observed for nitrate-N, Bray 1 P, and sulfate-S
• After 8 yeras of experimentation, the Check plots show the depletion of soil N, P, and S reserves; reaching only 64% of the wheat yeild of the NPS treatment.
• Wheat yields in 2008 were greatly affected by the severe drought that affected the region, and also by freezing on jointing stages.
• Significant responses were to P and NPS at La Blanca, to NS and NP at La Hansa, and to PS and NP at Lambaré.
• Water use efficiency (WUE) increased when N, P and/or S defeiciencies were eliminated, averages of 4.9 kg/mm for the Check and 7.3 kg/mm for the NPS treatment.
• Considering 22 of the 31 sites of the six wheat seasons evaluated, a significant relationship between wheat yield and soil nitrate-N + fertilizer n at planting was established. Wheat yields of 4000 kg/ha might be reached with soil N availability of 130-140 kg N/ha.
• P responses are highly probable at sites with soil Bray 1 P lower than 15 ppm, and no responses were observed at sites where soil Bray 1 P was greater than 20 ppm.
• S responses were not related to soil sulfate-S availability.

To see the full 2008 Wheat Report, please click here,
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