Radiation interception, extinction coefficient and use efficiency of wheat crop at various irrigation and nitrogen levels in a semi-arid location

Abstract

Field experiments were conducted to study the effect of irrigation and nitrogen levels on radiation use efficiency (RUE), radiation extinction coefficient (κ) and temporal variation of leaf area index (LAI) and fraction intercepted photosynthetically active radiation (fIPAR). The LAI of wheat increased with increase in irrigation and nitrogen levels. The fIPAR also followed trend similar to LAI. The LAI and fIPAR showed logarithmic relationship with R2 value of 0.92 and 0.93 for the years 2013–2014 and 2014–2015, respectively. The κ value varied between 0.41 and 0.78 and was significantly affected by nitrogen levels but was not influenced by irrigation levels. The grain and above ground biomass (AGB) yields of wheat were not affected significantly by irrigation levels. However, application of 160 kg N ha−1 (N160) registered higher grain (12–33%) and AGB (22–25%) yeilds as compared to that with application of 40 kg N ha−1 (N40). Similar to AGB, the total intercepted photosynthetically active radiation (TIPAR) was not affected by irrigation levels but N160 treatment registered 9–20% higher TIPAR compared to N40 treatment. The linear relationship between TIPAR and AGB revealed that 83–86% variation in AGB yield of wheat can be explained by TIfIPAR. The RUE of wheat under three irrigations (I3) was 6 and 18% higher (P < 0.05) than the five (I5) and two (I2) irrigation treatments, respectively for the year 2013–2014. However, there was no significant effect of irrigation on RUE of wheat in the year 2014–2015. N160 treatment registered 5–13% higher RUE than the N40 treatment. Thus wheat may be grown with three irrigations (CRI, flowering and grain filling) and 160 kg N ha−1 for higher RUE without significant reduction in AGB of wheat compared to five irrigation levels in semi-arid location of Delhi region.

Dissecting Bread Wheat Heterosis through the Integration of Agronomic and Physiological Traits

“…Besides measuring agronomic traits, we also used NDVI measurements, a nondestructive and heritable method which provides information on leaf area and radiation intercepted by the canopy [65,66]. Monitoring NDVI all along the plant development allowed us to model the different phases and to identify "stay green" varieties, i.e., those with a delayed senescence, a trait that has been shown to impact positively yield in pure lines [34].…”

Study on Radiation Interception and Use in Some Mustard Varieties

“…The RUE of the seasonal changes (i.e., temporal) was calculated as the difference in the total crop dry weight between two consecutive measurements divided by the corresponding amount of PAR intercepted [10][11]. The seasonal mean RUE was computed as the slope of the linear regression of the cumulative biomass plotted against the corresponding amount of PAR intercepted [9].…”

Seasonal Variation in Photosynthetically Active Radiation Interception and Radiation Use Efficiency in Green Gram [Vigna radiata (L.)Wilczek] in Lower Gangetic Plain of India

“…This was due to greater LAI during these two growth stages. It was reported that higher PAR interception in wheat due to greater LAI [30].…”

“…The LAI has an immense importance in capturing the radiation falling over the canopies [22,30]. The foliage structure, canopy architecture and cloud condition regulate the availability of solar radiation to the crop canopy [31,32].…”