title: [Utilization rate of fertilizer N and dynamic changes of soil NO3(-)-N in summer maize field in semi-humid area of Northwest China].
abstract: A field experiment on manual loessial soil was conducted to study the dynamic changes of NO3(-)-N in soil profile, utilization rate of fertilizer N, and relationships between N application rate and soil residual N accumulation during the growth period of summer maize under different N application rates (0, 45, 90, 135, and 180 kg hm(-2)). The results showed that in the whole growth period of summer maize, the NO3(-)-N concentration in the soil profile was the highest in 0-20 cm layer, and increased with increasing N application rate. The NO3(-)-N concentration in 0-60 cm soil layer changed significantly, but no significant change was observed in 60-100 cm soil layer. In the growth season of summer maize, soil NO3(-)-N accumulation presented a fluctuated decreasing trend due to the N uptake by crop and the precipitation. The N utilization rate (NUR) increased with increasing N application rate when the application rate was less than 135 kg hm(-2), but tended to decrease when the application rate exceeded 135 kg hm(-2). With the increase of N application rate, the N agronomy efficiency (NAE) decreased but the N physiology efficiency (NPE) increased. There was a significant positive correlation between soil residual N accumulation and N application rate (R2 = 0.957**, n = 5). The grain yield under N application was significantly higher than that without N application (P <0.05), and there existed a significant positive correlation between grain yield and N application rate (R2 = 0.934**, n = 5). In our experiment, the optimal application rate of fertilizer N was 135 kg hm(-2), which could harmonize the relationship between economic benefits and environment.
authors.affiliation: State Key Laboratory of Soil Erosion and Dry Land Farming on Loess Plateau, Northwest A & F University, Chinese Academy of Sciences, Yangling 712100, Shaanxi, China. ynf2411@126.com
authors.forename: Ya-ning
authors.initials: YN
authors.lastname: Fan
authors.forename: Shi-qing
authors.initials: SQ
authors.lastname: Li
authors.forename: Sheng-xiu
authors.initials: SX
authors.lastname: Li
mesh_terms: D002681:China; D005308:Fertilizers; D006813:Humidity; D009566:Nitrates / Q000032:analysis / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D012621:Seasons; D012987:Soil / Q000032:analysis*; D003313:Zea mays / Q000254:growth & development / Q000378:metabolism*
chemical_list: D005308:Fertilizers; D009566:Nitrates; D012987:Soil; D009584:Nitrogen