Differential fertilizer nitrogen fates in maize cropping system among three soil textures based on 15N.

Understanding the differential fertilizer N fates among soil textures is important to optimize crop nitrogen (N) management for reducing N losses while enhancing crop yields and N use efficiency. In this study, two-year field experiments were conducted on three contrasting soil textures (clay, sandy and loamy soils) with an identical climate in Northeast China, to quantify fertilizer N fates in the maize cropping system and evaluate their responses to N rates (168, 240, and 312 kg N ha−1) under different soil textures using 15N tracer technique, further to model fertilizer N fates with soil properties using multiple linear regression. In two seasons, both grain yields and plant N accumulation were the highest on loamy soil, followed by clay soil, while the lowest on sandy soil. Compared with loamy and clay soils, the plant N accumulation derived from fertilizer (Ndff%) was significantly higher (47 %) on sandy soil in the 1st season, meanwhile its poor soil structure increased environmental N losses (ENL) while decreasing crop N recovery (CNR) and soil N residual (SNR); together with higher in-season ENL, this further significantly lower Ndff% (6%) on sandy soil in the 2nd season. Relative to loamy soil, the SNR on clay soil was significantly higher in both seasons due to the denser and heavier soil texture, but its CNR was lower in the 1st season while both CNR and ENL were higher in the 2nd season. Throughout two growing seasons, the total CNR of loamy, clay and sandy soil was 44 %, 34 % and 28 %, the total ENL was 41 %, 46 % and 64 %, and the final SNR was 15 %, 20 % and 8 %, respectively. With increasing N rates, total CNR decreased while final SNR increased on all three soils, and ENL increased in the 1st season but decreased in the 2nd season. Moreover, the N responses of CNR and SNR were higher on sandy soil, indicating that its fertilizer N fates were more susceptible to N rates. Therefore, crop N management strategies are required to be adjusted according to differential fertilizer N fates among soil textures. By establishing the model between fertilizer N fates with soil properties and N rates, we provided a promising approach to understand and predict fertilizer N use and loss for precisely optimizing N managements on different soil textures. [Display omitted] • Crop 15N recovery was higher on loamy soil (43.8 %) relative to clay soil (34.4 %) and sandy soil (28.1 %). • Soil 15N residual was higher on clay soil (19.6 %) relative to loamy soil (14.9 %) and sandy soil (7.6 %). • Total 15N loss was higher on sandy soil (64.3 %) relative to clay soil (46.0 %) and loamy soil (41.2 %). • The higher Ndff in 1st year but the lower Ndff in 2nd year were obtained on sandy soil than other soils. • Modelling the relationships between fertilizer 15N fates and the soil structure and N rates. [ABSTRACT FROM AUTHOR]