Radiation-use efficiency and the harvest index of winter wheat at different nitrogen levels and their relationships to canopy spectral reflectance

Abstract

Abstract. Radiation-use efficiency (RUE, g/MJ) and the harvest index (HI, unitless) are two helpful characteristics in interpreting crop response to environmental and climatic changes. They are also increasingly important for accurate crop yield simulation, but they are affected by various environmental factors. In this study, the RUE and HI of winter wheat and their relationships to canopy spectral reflectance were investigated based on the massive field measurements of five nitrogen (N) treatments. Crop production can be separated into light interception and RUE. The results indicated that during a long period of slow growth from emergence to regreening, the effect of N on crop production mainly showed up in an increased light interception by the canopy. During the period of rapid growth from regreening to maturity, it was present in both light interception and RUE. The temporal variations of RUE APAR (aboveground biomass produced per unit of photosynthetically active radiation absorbed by the canopy) during the period from regreening to maturity had different patterns corresponding to the N deficiency, N adequacy and N-excess conditions. Moreover, significant relationships were found between the RUE APAR and the accumulative normalised difference vegetation index (NDVI) in the integrated season (R 2 = 0.68), between the HI and the accumulative NDVI after anthesis (R 2 = 0.89), and between the RUE grain (ratio of grain yield to the total amount of photosynthetically active radiation absorbed by the canopy) and the accumulative NDVI of the whole season (R 2 = 0.89) and that after anthesis (R 2 = 0.94). It suggested that canopy spectral reflectance has the potential to reveal the spatial information of the RUE APAR , HI and RUE grain . It is hoped that this information will be useful in improving the accuracy of crop yield simulation in large areas.

Association of digital photo parameters and NDVI with winter wheat grain yield in variable environments

“…The predictive value of NDVI for grain yield and other traits can be improved via some modifications in NDVI calculations, such as degree of NDVI reduction after anthesis (Hazratkulova et al, 2012), NDVI ratio before and after anthesis, and cumulative NDVI after anthesis (Li et al, 2011). There is value in relating spectral reflectance parameters to canopy and air temperature to reduce the effect of weather and differences related to maturity variation between genotypes (Kimball et al, 2012).…”

“…The optimal stages for measuring NDVI vary depending on the germplasm and environment (Marti et al, 2007;Li et al, 2011). Breeding programs usually pay little attention to field observations prior to heading, as there is limited Additional treatment for DYT: removal of aboveground biomass prior to stem elongation to apply more stress on crop.…”

Agronomic and physiological responses of Chinese facultative wheat genotypes to high-yielding Mediterranean conditions

“…In fact, reports on modern genotypes from Henan of plant heights between 0•70 and 0•80 m were not uncommon (Zhou et al 2007(Zhou et al , 2014. Sub-optimal plant heights in the Chinese cultivars may be associated with reductions in radiation-use efficiency (Li et al 2011). This may be the cause of Chinese cultivars from Henan having the tendency to suffer yield penalties when certain stresses affect culm growth.…”

Impact of water stress on radiation interception and radiation use efficiency of Soybeans (Glycine max L. Merr.) in Nigeria

“…The harvested biomass was oven dried at 70 °C for 24 h until constant weight (Farahani et al 2009;Li et al 2011). The DAB per unit area in each treatment was estimated.…”