The role of stomatal conductance for water and radiation use efficiency of durum wheat and triticale in a Mediterranean environment

2013 ◽  
Vol 44 ◽  
pp. 87-97 ◽  
Author(s):  
Rosella Motzo ◽  
Giovanni Pruneddu ◽  
Francesco Giunta
2011 ◽  
Vol 62 (1) ◽  
pp. 39 ◽  
Author(s):  
Simona Bassu ◽  
Francesco Giunta ◽  
Rosella Motzo

Field studies were conducted on durum wheat to assess the effects of three sowing dates and three cultivars with different flowering times on the stability of the biomass accumulated per unit of solar radiation intercepted that is usually considered constant in crop-simulation models. Aboveground dry matter varied widely, with minimum values ranging from 292 g m–2 at booting to 384 g m–2 at maturity and maximum values ranging from 1452 g m–2 at booting to 2565 g m–2 at maturity. The cumulative intercepted radiation at each phenological stage decreased as sowing was delayed. The leaf area index (LAI) ranged from 1.5 to 7.6 at booting and from 0.1 to 4.6 at the beginning of grain filling across treatments. Sowing dates and cultivars did not differ significantly in extinction coefficient values (0.38 ± 0.015). The estimated radiation use efficiency (eRUE) differed significantly between the two seasons (1.16 ± 0.09 g MJ–1 in 2000 and 1.61 ± 0.08 g MJ–1 in 2001) due to waterlogging in 2000 but did not differ among sowing dates and cultivars within each season. Under optimal growing conditions, eRUE of different cultivars of durum wheat were relatively stable across sowing dates, confirming their reliability for crop modelling in durum wheat as well as in bread wheat. Although eRUE was constant over the whole crop cycle regardless of the sowing date, it was lower at pre-anthesis in the latest sowing, in parallel with the variation in LAI. This study indicates that pre-anthesis eRUE may vary with sowing date under some conditions, depending on the variation in LAI in the period before anthesis.


2014 ◽  
Vol 4 (1) ◽  
pp. 26 ◽  
Author(s):  
Hatem Cheikh M'hamed ◽  
Mourad Rezig ◽  
Mbarek Ben Naceur

<p>On-farm trial was conducted from 2005 to 2008 to test the hypothesis that reduction of total dry matter (TDM) in crops can occur after a decreased radiation use efficiency (RUE) due to shortage of nitrogen and irrigation, we applied three irrigations treatments (D1, D2 and D3) and four nitrogen rates (N1, N2, N3 and N4). Photosynthetic active radiation absorbed or cumulative light interception (PARabs) and RUE of Durum wheat were measured. Results showed that D1N1 treatment recorded the highest LAI, PARabs, TDM and RUE. The maximum LAI was obtained 140 DAS (days after sowing) under treatment D1N2 (6.42) and the lowest LAI at the same phase belonged to treatment D2N4 (3.86). At the harvest, the maximum of TDM was 1487 g m<sup>-2</sup> recorded under treatment D1N1. The minimum value obtained was 930 g m<sup>-2</sup> under treatment D3N4. Also, PARabs was improved under D1N1 and D1N2 treatments. With reduced N application rates and irrigation doses, PARabs was decreased and the lowest values were observed under D3N4 condition. The RUE, varied from 1.55 g MJ<sup>-1</sup> (D1N1) to 1.24 g MJ<sup>-1</sup> (D3N4), was affected and decreased under deficit irrigation and low nitrogen conditions. In conclusion, the results of this study seem to show that D1N1 and D1N2 treatments can be beneficial for Durum wheat under field conditions in semi arid zone of Tunisia, for the purpose of improving RUE and maximizing grain yield.</p>


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 ◽  
...  

2015 ◽  
Vol 5 (2) ◽  
pp. 36
Author(s):  
Mourad Rezig ◽  
Hatem Cheikh M'hamed ◽  
Mbarek Ben Naceur

<p class="4Body">Total Dray Matter (TDM), Photosynthetically Active Radiation Intercepted (PARabs), Water Consumption (WC), Water use- (WUE), Radiation use efficiency (RUE) and the Relation between Radiation Interception and Water Consumption for Durum Wheat were investigate under different irrigation amount (D<sub>1</sub>= 100 % ETc; D<sub>2</sub>= 70 % ETc; D<sub>3</sub>= 40 % ETc and D<sub>4</sub>= pluvial) and during three growing seasons (2005-2006, 2006-2007 and 2007-2008). Results showed that, the cumulative PARabs decreased with deficit irrigation. In fact, D<sub>1</sub> treatment recorded the highest cumulative PAR abs and the lowest marked under D<sub>4</sub> treatment. Similarly, TDM and RUE were decreased with deficit irrigation. The highest RUE observed under the D<sub>1</sub> (from 1.32 to 1.43 g MJ<sup>-1</sup>) and the lowest under D<sub>4</sub> (from 1.17 to 1.29 g MJ<sup>-1</sup>). However WUE increased with deficit irrigation. The highest WUE were obtained under the D<sub>4</sub> (from 3 to 4 kg m<sup>-3</sup>) and the lowest were observed under D<sub>1</sub> (from 2.8 to 3.1 kg m<sup>-3</sup>). Significant linear relationship was found between cumulative PAR abs and cumulative water consumption with a high correlation coefficient (R<sup>2</sup>) only under the two treatments D<sub>1</sub> and D<sub>2</sub>.</p>


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