不同氮效率春玉米品种临界氮浓度稀释曲线建立与验证

Construction and verification of critical nitrogen dilution curve for spring maize varieties with different nitrogen efficiencies

  • 摘要: 采用田间定位试验, 以山西省晋中地区春玉米各生育时期地上部干物质量与植株氮浓度的变化规律, 建立春玉米临界氮浓度稀释曲线模型, 为实现春玉米绿色增产与氮素管理提供理论依据。本研究以玉米品种‘郑单958’和‘大丰26’为试验材料, 设4个施氮量处理: 0 kg(N)∙hm−2 (N0)、120 kg(N)∙hm−2 (N120)、240 kg(N)∙hm−2 (N240)和360 kg(N)∙hm−2 (N360), 于2014—2016年在山西农业大学东阳试验基地开展3年定位施氮试验, 在春玉米拔节期(V6)、抽雄期(VT)、灌浆期(R2)和成熟期(R6)采集植株样品, 分析两个春玉米品种在不同施氮量处理下地上部干物质量、籽粒产量(以下简称“产量”)和各生育时期植株氮浓度, 以不同生育时期干物质累积量和植株氮浓度, 建立并验证两个春玉米品种的临界氮浓度稀释曲线模型。结果表明, ‘郑单958’氮素利用率高于‘大丰26’。两个春玉米品种在适宜施氮量条件下, 各生育时期地上部干物质量和产量均随施氮量增加呈增加趋势, 地上部干物质量在N240和N360处理间差异不显著, 产量在N240处理达最大值; 植物氮浓度随施氮量增加而增加, 随春玉米生育进程推进与地上部干物质量呈幂指数关系。依据春玉米地上部干物质量(Md)与其对应的植株氮浓度(CN)变化关系, 建立两个春玉米品种的临界氮浓度稀释曲线模型: ‘郑单958’ CN=30.457Md0.292, ‘大丰26’ CN=33.249Md0.333。相比‘大丰26’的模型参数, ‘郑单958’的模型参数a降低8.40%, 参数b降低12.31%; ‘郑单958’和‘大丰26’模型均方根误差(RMSE)分别为1.71 g∙kg−1和1.54 g∙kg−1, 标准化均方根误差(n-RMSE)分别为9.25%和8.27%, 表明模型稳定性较好。氮营养指数在同一生育时期随施氮量增加呈上升趋势, 随生育时期推进呈先增加后降低趋势, 与各生育时期的相对干物质量呈显著线性相关, 与相对产量呈显著的一元二次曲线关系。本研究建立的晋中地区两个春玉米品种临界氮浓度稀释曲线模型及各生育时期氮营养指数, 可用于春玉米生育时期营养状况的诊断和评估, 结合施氮量与产量的关系, 推荐该试验区域‘郑单958’施氮量为189.16~224.08 kg∙hm−2, ‘大丰26’ 施氮量为199.72~214.67 kg∙hm−2

     

    Abstract: This study investigated the effects of varying nitrogen application rates on spring maize to establish a critical nitrogen dilution curve based on variations in aboveground dry matter weight and plant nitrogen concentration at different growth stages. The objective is to provide a theoretical basis for the sustainable development and rational application of nitrogen fertilizers for spring maize in central Shanxi Province, China. Field experiments with the maize varieties ‘Zhengdan958’ (ZD958) and ‘Dafeng26’ (DF26) were conducted at the Dongyang Experiment Base of Shanxi Agricultural University from 2014 to 2016. Four nitrogen application treatments were tested: 0 kg(N)∙hm−2 (N0), 120 kg(N)∙hm−2 (N120), 240 kg(N)∙hm−2 (N240), and 360 kg(N)∙hm−2 (N360). Plant samples were collected at the jointing (V6), tasseling (VT), filling (R2), and maturity (R6) stages. The aboveground dry matter weight, yield, and plant nitrogen concentration at each growth stage were analyzed for both spring maize varieties under different nitrogen application rates. The critical nitrogen concentration dilution curve models for the two spring maize varieties were established and verified based on the aboveground dry matter weight and plant nitrogen concentration at various growth stages. Results indicated that ZD958 exhibited a higher nitrogen utilization rate than DF26. For both varieties, aboveground dry matter weight and yield enhanced with increasing nitrogen application rates at each growth stage. However, no significant difference in aboveground dry matter weight was observed between the N240 and N360 treatments, with the maximum grain yield being achieved under the N240 treatment. Under the conditions of suitable nitrogen application, plant nitrogen concentration increased with increasing nitrogen application, and showed a power exponential relationship with the growth period of the aboveground dry matter weight. Based on the relationship between aboveground dry matter weight (Md) and plant nitrogen concentration (CN) of spring maize, the critical nitrogen concentration dilution curve models were established as follows: for ZD958, CN = 30.457 Md−0.292, and for DF26, CN = 33.249 Md−0.333. Compared to the model parameters of DF26, parameter a of ZD958 decreased by 8.40%, and parameter b decreased by 12.31%. The model showed a linear correlation between the fitted and actual plant nitrogen concentrations, with root mean square errors (RMSE) of 1.71 g∙kg−1 and 1.54 g∙kg−1, and standard root mean square errors (n-RMSE) of 9.25% and 8.27%, respectively. The nitrogen nutrition index calculated from the critical nitrogen concentration curves increased with nitrogen application within the same growth stage, initially increasing and then decreasing with the growth period. There was a significant linear correlation between the nitrogen nutrition index and relative aboveground dry matter weight at each growth stage, while the relationship between the nitrogen nutrition index and relative yield followed a quadratic curve. These results suggest that the nitrogen nutrition index can be used to determine the nitrogen nutritional status of spring maize. In conclusion, the established critical nitrogen concentration dilution curve models and nitrogen nutrition indexes for the two spring maize varieties can be used to diagnose and evaluate the nutritional status of spring maize during its growth stages. Based on the relationship between nitrogen application rate and yield, it is recommended that the nitrogen application rate for ZD958 should be between 189.16 and 224.08 kg(N)·hm−2, and for DF26 between 199.72 and 214.67 kg(N)·hm−2.

     

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