Spectral estimates of the absorbed photosynthetically active radiation and light-use efficiency of a winter wheat crop subjected to nitrogen and water deficiencies†
Spectral estimates of the absorbed photosynthetically active radiation and light-use efficiency of a winter wheat crop subjected to nitrogen and water deficiencies†
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DOI：
10.1080/01431169008955130
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发表时间：
1990-10
期刊：
影响因子：
5
通讯作者：
S. Steinmetz;M. Guérif;R. Delécolle;F. Baret
中科院分区：
文献类型：
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作者：
S. Steinmetz;M. Guérif;R. Delécolle;F. Baret
摘要 建立了一个线性回归方程，将通过半球照片测量的冠层拦截的光合有效辐射 (PARi) 与归一化差值 ND 和 NIR/R 植被指数比值联系起来。根据该方程，NIR/R 用于估算作物周期期间的 PARi。针对作物的三个物候阶段计算作物吸收的 PAR 转化为生物量 (ϵc) 的效率。施氮肥是影响截光的主要因素。在孕穗阶段，氮水平较高的处理的 PARi 大约高出 15%。 ϵc 受氮肥和灌溉水平的影响，并随作物的物候阶段而变化。对于灌溉地块，εc 在从开花到软面团期间较高，而不是在从茎伸长到开花期间较高，正如大多数已发表的结果所表明的那样。水分胁迫是影响εc的主要因素。 ;ϵc 的最大减少是...
Abstract A linear regression equation is found relating the photosynthetically active radiation intercepted by the canopy (PARi), measured with hemispherical photographs, and both the normalized difference ND and the ratio NIR/R vegetation indices. On the basis of this equation, NIR/R is used to estimate PARi during the crop cycle. The efficiency with which the PAR absorbed by the crop is transformed into biomass (ϵc) is calculated for three phenological phases of the crop. Nitrogen fertilization is the main factor affecting light interception. At the booting stage, PARi is about 15 per cent greater for treatments with higher nitrogen levels. ϵc is influenced by both nitrogen and irrigation levels, and varies with the phenological phases of the crop. For the irrigated plots, ϵc is higher in the period going from anthesis to soft dough and not in the period from stem elongation to anthesis as most published results indicate. Water stress is the main factor affecting ϵc. The greatest reductions of ;ϵc are o...