摘要
【目的】基于花冠层可见光数字图像特征研究油菜开花过程对不同氮肥用量的响应规律,为实现氮素养分精准管理而提升油菜花用模式的经济和生态价值提供技术支撑。【方法】利用无人机采集不同氮肥梯度[N_(0)(0 kg/ha)、N_(90)(90 kg/ha)、N_(180)(180 kg/ha)、N_(270)(270 kg/ha)和N_(360)(360 kg/ha)]下油菜花冠层可见光数字图像,结合像素分割统计与CIELab颜色空间解析,通过花冠层像素面积指数(FAI)、理论花期(S_(f))、平均每日FAI累计量(M_(Ave))、FAI增长速率(V_(up))、FAI衰减速率(V_(down))及CIELab颜色空间b^(*)等参数,探究油菜开花过程对不同氮肥用量的响应规律。【结果】随着氮肥施用量的增加,油菜花期呈逐渐推迟且缩短的变化趋势,具体表现为理论始花期(E)、盛花期(F)、终花期(B)分别延迟42.7%~129.4%、10.3%~26.7%和0.0%~4.7%,S_(f)从25.1 d(N_(0)处理)缩短至12.3 d(N_(360)处理)。M_(Ave)随氮肥施用量的增加呈先增加后下降的变化趋势,在N_(180)处理下达峰值,较N_(0)处理提升了56.3%。各氮肥梯度处理的油菜盛花期花冠层图像CIELab颜色空间b^(*)均呈偏态分布,随氮肥施用量的增加,b^(*)分布的中位数和众数均呈先增加后下降的变化趋势,以N_(90)处理的花冠层黄色饱和度最佳(b^(*)的中位数为0.685,众数为0.804),而N_(270)处理和N_(360)处理的花色变淡。在油菜花期氮肥响应综合评价方面,以N_(90)处理和N_(180)处理的加权综合评分最高(0.60分)。通过构建氮肥施用量与S_(f)、M_(Ave)和b^(*)的拟合方程,得知桂北地区油菜S_(f)和M_(Ave)达到平衡且油菜花朵黄色饱和度较高的最佳氮肥施用量为118.9 kg/ha,适宜氮肥施用量区间在90~180 kg/ha。【结论】基于花冠层可见光数字图像特征可有效揭示油菜开花过程对氮肥施用量的效应机制,进而简化油菜开花动态研究。在当前气候多变的背景下,氮素缺乏或过量均会放大温度胁迫下花期群体不稳定性,而适量施用氮肥(90~180 kg/ha)能促使营养与生殖生长达到平衡,从而规避气候风险。
【Objective】This study aimed to investigate the response of rapeseed to different nitrogen application rates during flowering period based on visible-light digital image features of corolla,thereby providing technical support for accurate management of nitrogen nutrient to improve economic and ecological value of rapeseed flower utilization mode.【Method】Visible-light digital images of rapeseed corolla under different nitrogen gradient treatments[N_(0)(0 kg/ha),N_(90)(90 kg/ha),N_(180)(180 kg/ha),N_(270)(270 kg/ha),and N_(360)(360 kg/ha)]acquired by unmanned aerial vehicle were analyzed through pixel segmentation statistics and CIELab color space interpretation,and parameters including flower area index(FAI),theoretical flowering period(S_(f)),average daily FAI accumulation(M_(Ave)),FAI increase rate(V_(up)),FAI decrease rate(V_(down)),and CIELab color space b^(*)were determined to investigate response of rapeseed to different nitrogen application rates during flowering period.【Result】As nitrogen application rate increased,rapeseed flowering period was gra dually delayed and shortened.Specifically,theoretical initial flowering stage(E),full bloom stage(F),and final flowe ring stage(B)were delayed by 42.7%-129.4%,10.3%-26.7%,and 0.0%-4.7%respectively;S_(f)decreased from 25.1 d under N_(0)treatment to 12.3 d under N_(360)treatment.M_(Ave)increased first and then decreased with the increase of nitrogen treatments,peaking under the N_(180)treatment,which was 56.3%higher than that under the N_(0)treatment.The distribution of CIELab color space b^(*)of rapeseed corolla image during full bloom stage was skewed under nitrogen gradient treatments.The median and mode of b^(*)distribution increased at first and then decreased with the increase of nitrogen application rate.The yellow saturation of corolla was the best under the N_(90)treatment(median of b^(*)was 0.685 and mode was 0.804),while the flower color under the N_(270)and N_(360)treatments faded.In terms of comprehensive evaluation of rapeseed response to nitrogen fertilizer during flowering period,the highest weighted comprehensive score(0.60 points)was observed under the N_(90)and N_(180)treatments.By constructing a fitting equation of nitrogen application rate and S_(f),M_(Ave),and b^(*),the optimal nitrogen application rate that could balance S_(f)and M_(Ave)and yield highly saturated yellow color in northern Guangxi was 118.9 kg/ha,and the appropriate range of nitrogen application rate was 90-180 kg/ha.【Conclusion】Visible-light digital images of corolla effectively elucidate the response mechanism of rapeseed to nitrogen application rates during flowe ring period,further simplifying studies on rapeseed flowering dynamics.Given that under the background of shifting climate,nitrogen deficiency or excess can amplify population instability during flowering period under temperature stress,and appropriate nitrogen fertilizer application(90-180 kg/ha)can balance nutrition,reproduction,and growth,thereby mitigating climate risks.
作者
明日
张宗急
李云娟
曾忠文
毛玲莉
程芳丽
毛凤玲
钟丽
黄婕
廖洁
MING Ri;ZHANG Zong-ji;LI Yun-juan;ZENG Zhong-wen;MAO Ling-li;CHENG Fang-li;MAO Feng-ling;ZHONG Li;HUANG Jie;LIAO Jie(Guilin Branch of Guangxi Academy of Agricultural Sciences/Guilin Agricultural Science Research Center,Guilin,Guangxi 541006,China;Agricultural and Rural Affairs Comprehensive Service Center of Xing’an County,Guilin,Guangxi 541300,China)
出处
《南方农业学报》
北大核心
2026年第2期340-349,共10页
Journal of Southern Agriculture
基金
广西自然科学基金项目(2022GXNSFBA035444)
国家现代农业产业技术体系建设专项(CARS-12)。
关键词
油菜
花期
开花量
花色
氮肥
数字图像
rapeseed
flowering period
flowering quantity
flower color
nitrogen fertilizer
digital image
