Nitrogen mineralization indicators under semi-arid and semi-humid conditions: influence on wheat yield and nitrogen uptake
2018
Martínez, Juan M. | Galantini, Juan A. | Duval, Matías E. | Landriscini, María Rosa | García, Ramiro J. | López, Fernando
The objectives were i) to assess indicators for potential nitrogen (N) mineralization and ii) to analyze their relationships for predicting winter wheat (Triticum aestivum L.) growth parameters (yield and N uptake, Nᵤₚ) in Mollisols of the semi-arid and semi-humid region of the Argentine Pampas. Thirty-six farmer fields were sampled at 0–20 cm. Several N mineralization indicators, wheat grain yield and Nᵤₚ at physiological maturity stage were assessed. A principal component (PC) analysis was performed using correlated factors to grain yield and Nᵤₚ. The cluster analysis showed two main groups: high fertility and low fertility soils. In high fertility soils, combining PCs in multiple regression models enhanced the wheat yield and Nᵤₚ prediction significantly with a high R² (adj R² = 0.71–0.83). The main factors that explained the wheat parameters were associated with water availability and N mineralization indicator, but they differ according to soil fertility. Abbreviations: N: nitrogen; SOM: soil organic matter; POM: particulate organic matter; SOC: soil organic carbon; SON: soil organic nitrogen; POM-C: particulate organic carbon; POM-N: particulate organic nitrogen; Nₐₙ: anaerobic nitrogen; Nₕyd: hydrolyzable N; NO₃-N: cold nitrate; N₂₀₅: N determined by spectrometer at 205 nm; N₂₆₀: N determined by spectrometer at 260 nm; Pe: extractable P; Nᵤₚ: wheat N uptake; NO₃-N: inorganic N in the form of nitrate; FR: fallow rainfalls (March-Seeding rainfall); FLR: flowering rainfalls (October-December rainfall); GFR: grain filling rainfall (November rainfall); CCR: crop growing season rainfall (June-December rainfall); PCA: principal component analysis; PC: principal component; MR: multiple regression
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