Time of nitrogen application affects nitrogen use efficiency of wheat in the humid pampas of Argentina

Abstract

. 2008. Time of nitrogen application affects nitrogen use efficiency of wheat in the humid pampas of Argentina. Can. J. Plant Sci. 88: 849Á857. Nitrogen (N) fertilization is an important management practice to increased grain yield; however, it is imperative to increase nitrogen use efficiency (NUE) in order to diminish risks of environmental pollution. The objective of this study was to determine the effect of fertilization times on wheat grain yield, grain N accumulation and grain N recovery efficiency (RE) in different sites and years at the south-eastern wheat belt of the Pampas. The experiments were a factorial combination of N rates and fertilization times (sowing and tillering). Grain yield ranged from 1600 to 7900 kg ha(1 and fertilization at tillering increased grain yield compared with fertilization at sowing (5465 vs. 5110 kg ha(1 ), similar behavior was observed for grain N accumulation (95 vs. 86 kg ha(1 ) and RE (0.41 vs. 0.32). Predicted grain yield by CERES-Wheat model for different N rates and fertilization times was correlated with observed grain yield (r 2 00.71). While fertilization at tillering significantly increased grain yield, CERES-Wheat model estimated nitrate leaching losses that ranged from 12 to 62 kg N ha(1 and from 7 to 16 kg N ha(1 for fertilization at sowing and tillering, respectively. However, denitrification losses ranged from 1.2 to 3.9 and from 0.5 to 2.4 kg N ha (1 for fertilization at sowing and tillering, respectively. Leaching losses for fertilization at sowing are a consequence of water excess early in the growing season and would be the main N loss factor. Therefore, N application at tillering is an appropriate strategy to improve NUE in the south-eastern wheat belt of the Pampas.

Delineation of management zones to improve nitrogen management of wheat

“…Peralta et al, 2014, found that NUE in similar field with barley crop varied between 1.3 and 18 kg of grain per kg N applied, which decreased as the applied N rate increased. Barbieri et al (2008) and Velasco et al (2012), found values similar to the present study, although they did not identify MZ. These authors mentioned that the low average values of NUE may be attributed to water stress during the growing season since in years without water stress, values of NUE were greater (see Fig.…”

“…In fields with spatially variable N needs, this practice leads to frequent mismatches between N fertilizer rate and crop N need. Over-application of N increases the probability of NO 3 -N leaching below the root zone (Aparicio et al, 2008;Barbieri et al, 2008) while underfertilization limits yields and may restrict economic returns (Scharf and Lory, 2002). Efficient N fertilizer management is critical for profitable crop production and long-term soil and environmental quality.…”

Alternatives for Nitrogen Diagnosis for Wheat with Different Yield Potentials in the Humid Pampas of Argentina

“…A similar behavior for that relationship was observed when NO 3 − -N content was determined at 0-40 cm deep (Figure 3). Lower yield related to N application at planting might be explained primarily by the occurrence of greater N loss by leaching and, to a lesser extent, by denitrification (Picone, Videla, and García 1997;Barbieri, Sainz Rozas, and Echeverría 2008). Greater NUE for N applications at tillering compared to planting have been also reported by other authors (Melaj et al 2003;Videla et al 2004;López Bellido, López Bellido, and López Bellido 2006;Barbieri, Sainz Rozas, and Echeverría 2008).…”

“…The greater proportion of soils are Typic Argiudolls, with loam texture at the surface layer, loam to clay loam at subsurface layers, and sandy loam below 110 cm deep, and Petrocalcic Paleudoll, which presents discontinuous layers of petrocalcic horizon below 0.8 m and greater clay contents at subsurface layers than Typic Argiudolls. More details of weather and soils in that area were described in Barbieri, Sainz Rozas, and Echeverría (2008).…”

Testing the use of an analytical and mechanistic C3 - biomass accumulation model for precision fertilization

“…When applying the nutrients this way, the synchrony between nitrogen availability and crop nitrogen demand , Shanahan et al 2008, Hancock et al 2011 can be enhanced and the threat of water soluble nutrients leaching to water systems can be decreased , Barberi et al 2008, Singh et al 2008, Basso et al 2011, Walsh et al 2013). Many studies have used split applications with predefined application rates (Esala 1991, Peltonen 1995, Olesen et al 2000, Asseng et al 2001, Kuisma 2002, Singh et al 2008, Basso et al 2009, Basso et al 2011, Hancock et al 2011) but observing the current growth conditions in defining the second application rate has also been suggested (Asseng et al 2001, Hakojärvi and Hautala 2010, Basso et al 2011, Walsh et al 2013.…”