scholarly journals A Simple Light-Use-Efficiency Model to Estimate Wheat Yield in the Semi-Arid Areas

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1524
Author(s):  
Saïd Khabba ◽  
Salah Er-Raki ◽  
Jihad Toumi ◽  
Jamal Ezzahar ◽  
Bouchra Ait Hssaine ◽  
...  
Keyword(s):  
Simple Model ◽  
Harvest Index ◽  
Wheat Yield ◽  
Growth And Yield ◽  
Light Use Efficiency ◽  
Proposed Model ◽  
Aquacrop Model ◽  
Use Efficiency ◽  
Semi Arid ◽  
Light Use Efficiency Model

In this study, a simple model, based on a light-use-efficiency model, was developed in order to estimate growth and yield of the irrigated winter wheat under semi-arid conditions. The originality of the proposed method consists in (1) the modifying of the expression of the conversion coefficient (εconv) by integrating an appropriate stress threshold (ksconv) for triggering irrigation, (2) the substitution of the product of the two maximum coefficients of interception (εimax) and conversion (εconv_max) by a single parameter εmax, (3) the modeling of εmax as a function of the Cumulative Growing Degree Days (CGDD) since sowing date, and (4) the dynamic expression of the harvest index (HI) as a function of the CGDD and the final harvest index (HI0) depending on the maximum value of the Normalized Difference Vegetation Index (NDVI). The calibration and validation of the proposed model were performed based on the observations of wheat dry matter (DM) and grain yield (GY) which were collected on the R3 irrigated district of the Haouz plain (center of Morocco), during three agricultural seasons. Further, the outputs of the simple model were also evaluated against the AquaCrop model estimates. The model calibration allowed the parameterization of εmax in four periods according to the wheat phenological stages. By contrast, a linear evolution was sufficient to represent the relationship between HI and CGDD. For the model validation, the obtained results showed a good agreement between the estimated and observed values with a Root Mean Square Error (RMSE) of about 1.07 and 0.57 t/ha for DM and GY, respectively. These correspond to a relative RMSE of about 19% for DM and 20% for GY. Likewise, although of its simplicity, the accuracy of the proposed model seems to be comparable to that of the AquaCrop model. For GY, R2, and RMSE values were respectively 0.71 and 0.44 t/ha for the developed approach and 0.88 and 0.37 t/ha for AquaCrop. Thus, the proposed simple light-use-efficiency model can be considered as a useful tool to correctly reproduce DM and GY values.

scholarly journals WATER USE EFFICIENCY, GROWTH AND YIELD OF WHEAT CULTIVATED UNDER COMPETITION WITH Setaria

2015 ◽  
Vol 33 (4) ◽  
pp. 679-687 ◽  
Author(s):  
M.Z. IHSAN ◽  
F.S. EL-NAKHLAWY ◽  
S.M. ISMAIL
Keyword(s):  
Drought Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Harvest Index ◽  
Wheat Yield ◽  
Negative Association ◽  
Growth And Yield ◽  
Yield Losses ◽  
Wheat Production ◽  
Use Efficiency

ABSTRACT Understanding the critical period of weed competition is indispensable in the development of an effective weed management program in field crops. Current experiment was planned to evaluate the critical growth period ofSetaria and level of yield losses associated with delay in weeding in rain-fed drip irrigated wheat production system of Saudi Arabia. Field experiment was conducted to evaluate the effect of weeding interval (07-21, 14-28, 21-35, 28-42 and 35-49 days after sowing) and drought stress (75% and 50% of field capacity) on Setaria growth, wheat yield and water use efficiency. Season long weedy check and wellwatered (100% FC) plots were also maintained for comparison. Weeding interval and drought stress significantly (p ≤ 0.05) affected the growth and yield of Setaria and wheat. Drought stress from 75% to 50% FC resulted in reductions of 29-40% in Setaria height, 14-27% in Setaria density and 11-26% in Setaria dry biomass. All weeding intervals except 35-49 DAS significantly suppressedSetaria growth as compared with control. Delay in weeding increased weed-crop competition interval and reduced wheat yield and yield contributors. Therefore, the lowest yield of 1836 kg ha-1 was attained for weeding interval of 35-49 DAS at 50% FC. Water use efficiency and harvest index increased with decreasing FC levels but reduced with delay in weeding. Correlation analysis predicted negative association ofSetariadensity with wheat yield and yield contributors and the highest negative association was for harvest index (-0.913) and water use efficiency (-0.614). Early management of Setaria is imperative for successful wheat production otherwise yield losses are beyond economical limits.

Growth and yield differences between triazine-tolerant and non-triazine-tolerant cultivars of canola

2002 ◽  
Vol 53 (6) ◽  
pp. 643 ◽  
Author(s):  
M. J. Robertson ◽  
J. F. Holland ◽  
S. Cawley ◽  
T. D. Potter ◽  
W. Burton ◽  
...  
Keyword(s):  
Harvest Index ◽  
Growth Analysis ◽  
Oil Content ◽  
Cropping Systems ◽  
Growth And Yield ◽  
Physiological Basis ◽  
Use Efficiency ◽  
The Difference ◽  
Radiation Extinction ◽  
Radiation Use

Canola tolerant to the triazine group of herbicides is grown widely in Australian broad-acre cropping systems. Triazine-tolerant (TT) cultivars are known to have a yield and oil content penalty compared with non-TT cultivars. This study was designed to elucidate the crop physiological basis for the yield differences between the two types. Two commercial cultivars, near-isogenic for the TT trait, were compared in a detailed growth analysis in the field, and 22 crops were compared for phenology and crop attributes at maturity. In the growth analysis study, the TT trait was found to lower radiation use efficiency, which carried through to less biomass at maturity. There were minimal effects on leaf area development and harvest index, and no effect on canopy radiation extinction. Across the 22 crops, where yield varied from 240 to 3400 kg/ha in the non-TT cultivar, yield was on average 26% less in the TT cultivar due to less biomass produced, as there was no significant effect on harvest index. The difference in oil content (2-5%) was greater in low oil content environments. Flowering was delayed by 2-10 days with a greater delay being in later flowering environments. Quantification of the physiological attributes of TT canola allows the assessment of the productivity of different cultivar types across environments.

Root pruning enhances wheat yield, harvest index and water-use efficiency in semiarid area

2019 ◽  
Vol 230 ◽  
pp. 62-71 ◽  
Author(s):  
Changlu Hu ◽  
Victor O. Sadras ◽  
Guoyan Lu ◽  
Runze Zhang ◽  
Xueyun Yang ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Harvest Index ◽  
Wheat Yield ◽  
Root Pruning ◽  
Semiarid Area ◽  
Use Efficiency

scholarly journals The effects of clouds and aerosols on net ecosystem CO<sub>2</sub> exchange over semi-arid Loess Plateau of Northwest China

2010 ◽  
Vol 10 (5) ◽  
pp. 13337-13372
Author(s):  
X. Jing ◽  
J. Huang ◽  
G. Wang ◽  
K. Higuchi ◽  
J. Bi ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Air Temperature ◽  
Northwest China ◽  
Co2 Uptake ◽  
Observation Data ◽  
Light Use Efficiency ◽  
Clearness Index ◽  
Use Efficiency ◽  
The Difference ◽  
Semi Arid

Abstract. The impacts of clouds and atmospheric aerosols on the terrestrial carbon cycle at semi-arid Loess Plateau in Northwest China are investigated, by using the observation data obtained at the SACOL (Semi-Arid Climate and Environment Observatory of Lanzhou University) site. Daytime (solar elevation angles of larger than 50°) NEE of CO2 obtained during the midgrowing season (July–August) are analyzed with respect to variations in the diffuse radiation, cloud cover and aerosol optical depth (AOD). Results show a significant impact by clouds and aerosols on the CO2 uptake by the grassland (with smaller LAI values) located in a semi-arid region, quite different from areas covered by forests and crops. The light saturation levels in canopy are lower, with a value of about 434.8 W m−2. Thus, under overcast conditions of optically thick clouds, the CO2 uptake increases with increasing clearness index, and a maximum CO2 uptake and light use efficiency of vegetation occur with the clearness index of about 0.37 and lower air temperature. Under other sky conditions the CO2 uptake decreases with the cloudiness but the light use efficiency is enhanced, due to increase in the fraction of diffuse PAR. Additionally, under cloudy conditions, changes in the NEE of CO2 also result from the interactions of many environmental factors, especially the air temperature. In contrast to its response to changes in solar radiation, the carbon uptake shows a negative response to increased AOD. The reason for the difference in the response of the semi-arid grassland from that of the forest and crop lands may be due to the difference in the canopy's architectural structure.

scholarly journals Combined application of nitrogen and phosphorus to enhance nitrogen use efficiency and close the wheat yield gap on varying soils in semi‐arid conditions

2019 ◽  
Vol 205 (6) ◽  
pp. 635-646 ◽  
Author(s):  
Therese M. McBeath ◽  
Vadakattu V. S. R. Gupta ◽  
Rick S. Llewellyn ◽  
Sean D. Mason ◽  
Christopher W. Davoren ◽  
...  
Keyword(s):  
Nitrogen Use Efficiency ◽  
Wheat Yield ◽  
Nitrogen And Phosphorus ◽  
Yield Gap ◽  
Nitrogen Use ◽  
Combined Application ◽  
Arid Conditions ◽  
Use Efficiency ◽  
Semi Arid

Enhanced coupling of light use efficiency and water use efficiency in arid and semi‐arid environments

Ecohydrology ◽  
2021 ◽  
Author(s):  
Dexin Gao ◽  
Shuai Wang ◽  
Lixin Wang ◽  
Zidong Li ◽  
Ning Pan ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Arid Environments ◽  
Light Use Efficiency ◽  
Use Efficiency ◽  
Semi Arid

Influence of nipping and foliar application of nutrients on growth and yield of chickpea in rain-fed condition

2018 ◽  
Author(s):  
Ejaz Ahmad Khan ◽  
Iqtidar Hussain ◽  
Sheryar . ◽  
Hafiz Bashir Ahmad ◽  
Iqbal Hussain
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Harvest Index ◽  
Foliar Application ◽  
Growth And Yield ◽  
Control Treatment ◽  
Biological Yield ◽  
Use Efficiency ◽  
1000 Grain Weight ◽  
Number Of Branches

Although,chickpea isnitrogen fixing crop but water scarcity under rain-fed condition reduces its nodulation process severely and nutrients use efficiency too. An experiment was carried out regarding the combined effect of nipping as well as foliar applied fertilizers on yield and yield components of chickpea under rain-fed conditions. Nipping and foliar application of nutrients significantly improved number of pods plant-1, biological yield (kg ha-1), harvest index (%) and final grain yield (kg ha-1). However, non-significant influence was seen in 1000-grain weight and number of grains pod-1. Foliar application of N PK (20:20:20) @2.5 kg ha-1 × nipping was found to be the best interaction among others which significantly increased number of branches plant-1 (11.30), number of pods plant-1(115.36), plant height(59.48cm) and grain yield(2338.9 kg ha-1) as compared to the control treatment. Nipping along with foliar application of NPKcan be practiced in chickpea for higher profitability.

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