scholarly journals Net Aerial Primary Productivity Models for Alfalfa Varieties (Medicago sativa L.) Derived from the Red Vegetation Index

2021 ◽  
Vol 8 (3) ◽  
pp. 167-182
Author(s):  
Jose Luis Tiedemann

The present study is aimed at quantifying and comparing the net aerial primary productivity (NAPP) of two alfalfa varieties (Medical sativa L.) by determining the Radiation Use Efficiency (Ɛ) for each variety, estimating the NAPP though the Red Vegetation Index and relating it to the quantified NAPP. Significant differences between the individual NAPP of each variety were not found: G969 = 1564 g dm m-2 and M901 = 1636 g dm m-2 (T = 0.92; p>0.05). The Ɛ of the G969 was 0.56 g Mj-1 while that of M901 was 0.58 g Mj-1. Significant direct relationships between the quantified NAPP and that calculated using the Red Vegetation Index were found. The models obtained were: NAPPG969 = 506.06x – 343.25 (R2 = 0.88; p<0.001) and NAPPM901 = 420.28x + 37.82 (R2 = 0.98; p<0.001). The Ɛ values of the alfalfa varieties under study, determined at local level, reduce uncertainty when generating predictive models of productivity. The NAPP of alfalfa varieties can be non-destructively predicted using the Red Vegetation Index obtained by a reflex RGB digital camera. Keywords: radiation use efficiency, digital camera, canopy reflectance, RGB indices

1992 ◽  
Vol 72 (3) ◽  
pp. 689-698 ◽  
Author(s):  
D. J. Major ◽  
H. H. Janzen ◽  
R. S. Sadasivaiah ◽  
J. M. Carefoot

Eight wheat (Triticum aestivum L.) cultivars including soft white spring, hard red spring, Canada Prairie Spring (CPS) and durum types were grown on rain-fed and irrigated land from 1987 to 1990 at Lethbridge, AB, to assess the relationship between yield components and radiation-use efficiency. Canopy reflectance measurements were used to estimate seasonal absorption of photosynthetically active radiation (APAR). At maturity, yield components including tillers per plant, heads per plant, kernels per head and kernel weight were determined. Whole-plant phytomass and grain yield were also determined. Harvest index was determined from the ratio of grain yield to whole-plant (excluding roots) phytomass and radiation-use efficiency (RUE) was calculated from the ratio of whole-plant phytomass to APAR. Significant grain yield differences confirmed that soft white and CPS wheats yielded more and responded more to irrigation than hard red or durum wheats. The yield components that were consistently different among cultivars were kernels per head and kernel weight which would be expected to increase if a consistent supply of assimilate was available during grain filling. Soft white and CPS wheats had higher harvest indices than the hard red or durum wheats, particularly under irrigation. Whole-plant phytomass was closely related to APAR and there were few differences among cultivars for RUE. There was no difference in RUE between rain-fed and irrigated treatments, indicating that there was probably no crop water stress on the rain-fed plots. RUE estimates for 1988 were lower than for the succeeding years, indicating an environmental or edaphic stress in that year.Key words: Remote sensing, radiation-use efficiency, yield components


2009 ◽  
Vol 19 (2) ◽  
pp. 253-267 ◽  
Author(s):  
Martín F. Garbulsky ◽  
Josep Peñuelas ◽  
Dario Papale ◽  
Jonas Ardö ◽  
Michael L. Goulden ◽  
...  

Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 101-110 ◽  
Author(s):  
S. Sridhara ◽  
T.G. Prasad

SUMMARYA field experiment was conducted at Gandhi Krishi Vignana Kendra, University of Agricultural Sciences, Bangalore to study the effect of irrigation regimens on the biomass accumulation, canopy development, light interception and radiation use efficiency of sunflower. The treatments includes irrigating the plants at 0.4, 0.6, 0.8 and 1.0 cumulative pan evaporation. The results indicated that the aboveground biomass, canopy development, radiation interception and radiation use efficiency were influenced favorably by the irrigation regimens. Irrespective of the irrigation regimen, the radiation use efficiency of sunflower increased from 15 DAS to 75 DAS and then tended to decline. The decrease in RUE after anthesis is coupled with decrease in leaf nitrogen content. In general the RUE of sunflower ranged from 0.49 g MJ-1 to 1.84 g MJ-1 at different growth stages. The light transmission within the canopy increased exponentially with plant height and the canopy extension coefficient is found to be 0.8.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 351
Author(s):  
Adolfo Rosati ◽  
Damiano Marchionni ◽  
Dario Mantovani ◽  
Luigi Ponti ◽  
Franco Famiani

We quantified the photosynthetically active radiation (PAR) interception in a high-density (HD) and a super high-density (SHD) or hedgerow olive system, by measuring the PAR transmitted under the canopy along transects at increasing distance from the tree rows. Transmitted PAR was measured every minute, then cumulated over the day and the season. The frequencies of the different PAR levels occurring during the day were calculated. SHD intercepted significantly but slightly less overall PAR than HD (0.57 ± 0.002 vs. 0.62 ± 0.03 of the PAR incident above the canopy) but had a much greater spatial variability of transmitted PAR (0.21 under the tree row, up to 0.59 in the alley center), compared to HD (range: 0.34–0.43). This corresponded to greater variability in the frequencies of daily PAR values, with the more shaded positions receiving greater frequencies of low PAR values. The much lower PAR level under the tree row in SHD, compared to any position in HD, implies greater self-shading in lower-canopy layers, despite similar overall interception. Therefore, knowing overall PAR interception does not allow an understanding of differences in PAR distribution on the ground and within the canopy and their possible effects on canopy radiation use efficiency (RUE) and performance, between different architectural systems.


2016 ◽  
Vol 53 (2) ◽  
pp. 210-225 ◽  
Author(s):  
GUILHERME M. TORRES ◽  
ADRIAN KOLLER ◽  
RANDY TAYLOR ◽  
WILLIAM R. RAUN

SUMMARYSeed-oriented planting provides a manner to influence canopy structure. The purpose of this research was to improve maize light interception using seed-oriented planting to manipulate leaf azimuth across the row thereby minimizing leaf overlap. To achieve leaf azimuths oriented preferentially across the row, seeds were planted: (i) upright with caryopsis pointed down, parallel to the row (upright); and (ii) laying flat, embryo up, perpendicular to the row (flat). These treatments were compared to conventionally planted seeds with resulting random leaf azimuth distribution. Seed orientation effects were contrasted with three levels of plant population and two levels of hybrid specific canopy structures. Increased plant population resulted in greater light interception but yield tended to decrease as plant population increased. The planophile hybrid produced consistently greater yields than the erectophile hybrid. The difference between planophile and erectophile hybrids ranged from 283 to 903 kg ha−1. Overall, mean grain yield for upright and flat seed placement increased by 351 and 463 kg ha−1 compared to random seed placement. Greater cumulative intercepted photosynthetically active radiation (CIPAR) was found for oriented seeds rather than random-oriented seeds. At physiological maturity upright, flat and random-oriented seeds intercepted 555, 525 and 521 MJ m−2 of PAR, respectively. Maize yield responded positively to improved light interception and better radiation use efficiency. Under irrigated conditions, precision planting of maize increased yield by 9 to 14% compared to random-oriented seeds.


1989 ◽  
Vol 20 (1) ◽  
pp. 51-64 ◽  
Author(s):  
J.R. Kiniry ◽  
C.A. Jones ◽  
J.C. O'toole ◽  
R. Blanchet ◽  
M. Cabelguenne ◽  
...  

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