施氮模式对玉-麦周年轮作系统产量和氮吸收利用的影响

为明确适宜豫北平原夏玉米-冬小麦一体化种植的高效施氮管理模式,2016—2017年分别在豫北典型高产田区河南省鹤壁市和中产田区河南省原阳县开展了夏玉米-冬小麦周年轮作不同施氮模式对夏玉米与冬小麦产量、氮素吸收和利用效率影响的田间试验。共设5种处理:不施氮肥(T1)、普通尿素按210 kg(N)?hm?2一次性基施(T2)、普通尿素分次施用且总施氮量同T2(T3)、控释尿素与普通尿素配比氮素减量施用(T4)和控释尿素与普通尿素配比氮素足量施用(T5)。分别于夏玉米和冬小麦关键生育期测试叶片SPAD值、植株与籽粒氮含量及生物量等氮营养指标,并于成熟期测定产量和产量构成因子,分析计算植株氮积累量与吸收利用特征。结果表明,处理间,高、中产区夏玉米与冬小麦产量、产量构成因子及氮素营养指标整体变化趋势均为T5T4T3T2T1。产区间,各处理夏玉米和冬小麦产量性状及氮营养指标均表现为高产区显著优于中产区。综合各处理平均值,高产区夏玉米产量、植株氮含量和氮素积累量相比于中产区分别平均提高58.0%、19.2%和47.1%,冬小麦增幅则分别为34.7%、33.3%和85.9%。氮利用效率方面,高、中产田在氮肥表观利用率、氮肥农学效率和100kg籽粒需氮量变化趋势均表现为T5T4T3T2T1,处理间差异显著;氮素收获指数则与此相反。豫北平原夏玉米-冬小麦周年轮作制在作物稳产甚至增产条件下,采用尿素与缓释氮肥掺混配施的氮肥优化施用模式不仅可有效减少肥料用量,还能显著提升肥料利用率,降低氮肥损失。

Effects of nitrogen application methodologies on yield and nitrogen use efficiencies in a summer maize (Zea mays)-winter wheat (Triticum aestivum) rotation system

This research was conducted to explore an appropriate nitrogen (N) management pattern for a summer maize (Zea mays)-winter wheat (Triticum aestivum) rotation system (SM-WW) and to study the effects of N application methodologies on crop yields and N use efficiencies in a SM-WW in high and medium yield areas of Henan Province, North China. An appropriate N management strategy was analyzed and established in this study. The detailed N application strategies for the SM-WW were as follows:(i) no N application (T1); (ii) one-off application of urea with the rate of 210 kg(N)·hm^-2 (T2); (iii) fractional application of urea with the rate of 210 kg(N)·hm^-2 (T3); (iv) combined application of controlled-release N fertilizer with urea at the rate of 180 kg (N)·hm^-2 for wheat and 195 kg (N)·hm^-2 for maize (T4); (v) combined application of controlled-release N fertilizer with urea at the rate of 210 kg(N)·hm^-2 for wheat and maize (T5). The Soil-Plant Analyses Development (SPAD) chlorophyll meter (Minolta Camera Co., Japan) was used to determine SPAD values. Plant and/or grain N content and biomass were measured at different growth stages for the SM-WW and used to calculate different N indicators. Results showed that N fertilization methodologies could significantly affect the yield, yield components, and N indicators among the five treatments, with the overall trend being T5 > T4 > T3 > T2 > T1. Moreover, the yield and N parameters in high-yield area were significantly higher than those in medium-yield area. Compared with the medium-yield condition, the average values among the five treatments for yield, plant N content, and accumulation increased by 58.0%, 19.2%, and 47.1% for maize and 34.7%, 33.3%, and 85.9% for wheat, respectively, under high-yield conditions. Regarding the N use efficiencies, from T1 to T5, apparent N use efficiency, agronomic N use efficiency, and N absorption amount for producing 100 kg of grain were increased both in the high-and medium-yield areas. However, the opposite trend was found for N harvest index. The results showed that an optimal N fertilization treatment, such as T4 or T5, had great potential in improving N use efficiency without adversely affecting grain yield and could be an appropriate model of N nutrient application during the SM-WW in Henan Province, China.