Effect of salinity on water stress, growth and yield of broadbeans

1992 ◽  
Vol 21 (1-2) ◽  
pp. 107-117 ◽  
Author(s):  
N. Katerji ◽  
J.W. van Hoorn ◽  
A. Hamdy ◽  
N. Bouzid ◽  
S.El-Sayed Mahrous ◽  
...  
1993 ◽  
Vol 23 (3) ◽  
pp. 247-265 ◽  
Author(s):  
J.W. van Hoorn ◽  
N. Katerji ◽  
A. Hamdy ◽  
M. Mastrorilli

1996 ◽  
Vol 30 (3) ◽  
pp. 237-249 ◽  
Author(s):  
N. Katerji ◽  
J.W. van Hoorn ◽  
A. Hamdy ◽  
F. Karam ◽  
M. Mastrorilli

Author(s):  
T. C. Hsiao ◽  
E. Fereres ◽  
E. Acevedo ◽  
D. W. Henderson

2020 ◽  
Vol 08 (01) ◽  
pp. 71-83 ◽  
Author(s):  
Jinya Su ◽  
Matthew Coombes ◽  
Cunjia Liu ◽  
Yongchao Zhu ◽  
Xingyang Song ◽  
...  

Water stress has adverse effects on crop growth and yield, where its monitoring plays a vital role in precision crop management. This paper aims at initially exploiting the potentials of UAV aerial RGB image in crop water stress assessment by developing a simple but effective supervised learning system. Various techniques are seamlessly integrated into the system including vegetation segmentation, feature engineering, Bayesian optimization and Support Vector Machine (SVM) classifier. In particular, wheat pixels are first segmented from soil background by using the classical vegetation index thresholding. Rather than performing pixel-wise classification, pixel squares of appropriate dimension are defined as samples, from which various features for pure vegetation pixels are extracted including spectral and color index (CI) features. SVM with Bayesian optimization is adopted as the classifier. To validate the developed system, a Unmanned Aerial Vehicle (UAV) survey is performed to collect high-resolution atop canopy RGB imageries by using DJI S1000 for the experimental wheat fields of Gucheng town, Heibei Province, China. Two levels of soil moisture were designed after seedling establishment for wheat plots by using intelligent irrigation and rain shelter, where field measurements were to obtain ground soil water ratio for each wheat plot. Comparative experiments by three-fold cross-validation demonstrate that pixel-wise classification, with a high computation load, can only achieve an accuracy of 82.8% with poor F1 score of 71.7%; however, the developed system can achieve an accuracy of 89.9% with F1 score of 87.7% by using only spectral intensities, and the accuracy can be further improved to 92.8% with F1 score of 91.5% by fusing both spectral intensities and CI features. Future work is focused on incorporating more spectral information and advanced feature extraction algorithms to further improve the performance.


2019 ◽  
Vol 11 (18) ◽  
pp. 5086 ◽  
Author(s):  
Libing Song ◽  
Jiming Jin ◽  
Jianqiang He

In this study, we investigated the effects of water stress on the growth and yield of summer maize (Zea mays L.) over four phenological stages: Seedling, jointing, heading, and grain-filling. Water stress treatments were applied during each of these four stages in a water-controlled field in the Guanzhong Plain, China between 2013 and 2016. We found that severe water stress during the seedling stage had a greater effect on the growth and development of maize than stress applied during the other three stages. Water stress led to lower leaf area index (LAI) and biomass owing to reduced intercepted photosynthetically active radiation (IPAR) and radiation-use efficiency (RUE). These effects extended to the reproductive stage and eventually reduced the unit kernel weight and yield. In addition, the chlorophyll content in the leaf remained lower, even though irrigation was applied partially or fully after the seedling stage. Severe and prolonged water stress in maize plants during the seedling stage may damage the structure of the photosynthetic membrane, resulting in lower chlorophyll content, and therefore RUE, than those in the plants that did not experience water stress at the seedling stage. Maize plants with such damage did not show a meaningful recovery even when irrigation levels during the rest of the growth period were the same as those applied to the plants not subjected to water stress. The results of our field experiments suggest that an unrecoverable yield loss could occur if summer maize were exposed to severe and extended water stress events during the seedling stage.


Crop Science ◽  
1980 ◽  
Vol 20 (6) ◽  
pp. 687-690 ◽  
Author(s):  
Nasser Sionit ◽  
H. Hellmers ◽  
B. R. Strain

2013 ◽  
Vol 308 ◽  
pp. 231-239 ◽  
Author(s):  
Sara Marañón-Jiménez ◽  
Jorge Castro ◽  
José Ignacio Querejeta ◽  
Emilia Fernández-Ondoño ◽  
Craig D. Allen

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