Site-Specific Quality Management in Wheat Results from the 2003 Field Trials in Argentina

BONGIOVANNI, R.; MÉNDEZ A.; ROBLEDO, C.W.; BRAGACHINI, M; PROIETTI, F.; SCARAMUZZA, F.; SPERANZA, F.; NISI, J. E.

Wheat Production in Stressed Environments

SPRINGER

Año: 2007; p. 203 - 208

Wheat fields in the semiarid region of Argentina are spatially variable in soil nitrogen (N) fertility and crop productivity. By accounting for spatial variation in soil N levels, variable-rate fertilizer application may improve crop yield and quality, and N use efficiency within fields. Therefore, there is interest in applying variable rates of fertilizer N across the landscape. The general objective of this research is to determine relationships among yield, protein and N rates using spatial regression analysis to yield monitor data as a means to optimize variable rate nitrogen fertilizer strategies in wheat for high protein levels in grain. The data were drawn from an on-farm N trial of 10.2 ha within a 44 ha field conducted in Manfredi, Córdoba, Argentina in 2003. The experimental design was a complete block strip trial that included two different types of soils in terms of landscape (hilltop and lowland) and two different antecessor crops (corn and soybeans). The fertilized strips were wider than the combine platform width, with zero N application as the control, and five other rates of N (12, 37, 62, 88 and 112 kg ha-1). Grain samples were collected directly from the grain flow of a combine harvester, analyzed for quality in the laboratory and converted into a GIS layer, together with the yield monitor data. Yield and grain quality variability was observed across the field, and among treatments. The combination of yield maps, soil moisture and protein content can help to determine management zones in order to maximize economic benefit. This approach offers opportunities to optimize grain protein on a site-specific basis by accounting for spatial variability of N fertility within individual fields