scholarly journals Using AquaCrop Model to simulate irrigation water use efficiency of potato crop under semi-arid conditions of Central Tunisia

2019 ◽  
Vol 6 (12) ◽  
pp. 223-231
Author(s):  
Hiba Ghazouani ◽  
Basma Latrech ◽  
Boutheina M. Douh ◽  
Cherni Amani ◽  
Mguidich Belhaj Amel ◽  
...  

In Tunisia, water scarcity forces producers to face stress conditions. In this study, AquaCrop was used to reproduce the dynamic of water contents, vegetative growth, yield production and water use efficiency under a non-stressed and water stressed treatments. Calibration procedure aimed to use in maximum default parameters of AquaCrop. Since, the paper presented only the parameters that have to be adjusted to obtain similar results of field measurements. Root mean squared error, RMSE, values were always lower than 0.04 cm3.cm-3 for water contents lower than 0.06 for vegetation cover estimation. Moreover, results from Nasch Coefficient, E, were almost equal to one. RMSE and E justified that the model was well assessed to predict the soil water contents and vegetation development under the study area. However, the model presented a greater performance in the case of full irrigation strategy. When evaluating different values of water productivity, it was showed that a WP of 32 g.m-2 produced the lowest estimation error. Regarding yield productions, statistical indictors, computed for a water productivity value of 32 g.m-2 show in general RMSE values lower than 0.4 t/ha. In addition, E was closer to one for the non stressed treatment, T1. For irrigation water use efficiency, it was depicted that the model underestimated field IWUE. Moreover, the discrepancy between simulated and estimated irrigation water use efficiency rose for treatment T2, implying that the model calibration should be improved, especially for stressed conditions. The model, after being calibrated, could be used for simulating the response of the crop to different irrigation management aiming to optimize water use efficiency.

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 39
Author(s):  
Chiara Corbari ◽  
Imen Ben Charfi ◽  
Marco Mancini

Remote sensing data of canopy cover and leaf area index are used together with the AquaCrop model to optimize irrigation water use efficiency for tomato and maize fields across Italy, which differ in climate, soil types and irrigation technique. An optimization irrigation strategy, “SIM strategy”, is developed based on crop stress thresholds and then applied to all the analyzed fields in different crop seasons, evaluating the effect not only on irrigation volume and number of irrigations but also on crop yield and canopy cover, and on the drainage flux which represents the main water loss. Irrigation volume reduction is found to be between 200 and 1000 mm, mainly depending on the different soil types within the climate, irrigation technique and crop type. This is directly related to the drainage flux reduction which is of a similar entity. The SIM strategy efficiency has then been quantified by different indicators, such as the irrigation water use efficiency (IWUE) which is higher than with the observed irrigations (around 35 % for tomato fields in Southern Italy, between 30 and 80% for maize in Northern Italy), and the percolation deficit and irrigation efficiency. The AquaCrop model has been previously calibrated against canopy cover and leaf area index (LAI) data, producing errors between 0.7 and 5%, while absolute mean errors (MAE) between 0.015 and 0.04 are obtained for soil moisture (SM). The validation of the AquaCrop model has been performed against evapotranspiration (ET) ground-measured data and crop yields producing MAE values ranging from 0.3 to 0.9 mm/day, and 0.9 ton/ha for maize and 10 ton/ha for tomatoes, respectively.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 228
Author(s):  
Ikram Ullah ◽  
Hanping Mao ◽  
Ghulam Rasool ◽  
Hongyan Gao ◽  
Qaiser Javed ◽  
...  

This study was conducted to investigate the effects of various irrigation water (W) and nitrogen (N) levels on growth, root-shoot morphology, yield, and irrigation water use efficiency of greenhouse tomatoes in spring–summer and fall–winter. The experiment consisted of three irrigation water levels (W: 100% of crop evapotranspiration (ETc), 80%, and 60% of full irrigation) and three N application levels (N: 100%, 75%, and 50% of the standard nitrogen concentration in Hoagland’s solution treatments equivalent to 15, 11.25, 7.5 mM). All the growth parameters of tomato significantly decreased (p < 0.05) with the decrease in the amount of irrigation and nitrogen application. Results depicted that a slight decrease in irrigation and an increase in N supply improved average root diameter, total root length, and root surface area, while the interaction was observed non-significant at average diameter of roots. Compared to the control, W80 N100 was statistically non-significant in photosynthesis and stomatal conductance. The W80 N100 resulted in a yield decrease of 2.90% and 8.75% but increased irrigation water use efficiency (IWUE) by 21.40% and 14.06%. Among interactions, the reduction in a single factor at W80 N100 and W100 N75 compensated the growth and yield. Hence, W80 N100 was found to be optimal regarding yield and IWUE, with 80% of irrigation water and 15 mM of N fertilization for soilless tomato production in greenhouses.


2019 ◽  
Vol 20 (1) ◽  
pp. 83-94 ◽  
Author(s):  
Liu Dong ◽  
Zhou Lihui ◽  
Li Heng ◽  
Fu Qiang ◽  
Li Mo ◽  
...  

Abstract The evaluation of irrigation water efficiency plays an important role in the efficient use of agricultural water resources and the sustainable development of agriculture. In order to make the evaluation of irrigation water use efficiency indicators more comprehensive and scientific, this paper constructs a new optimal model of evaluation indicators. By combining the Driver-Pressure-State-Impact-Response (DPSIR) model with the Information Significance Difference (ISD) evaluation indicators model, a novel DPSIR-ISD evaluation indicators combination model was constructed. Ten riverside irrigation areas in the Sanjiang Plain of northeastern China were selected for analysis. The results show that the DPSIR-ISD model was used to reduce the number of indicators from 44 to 14; these 14 indicators reflected 91.88% of the original information. The DPSIR-ISD method proposed in this paper takes into account the completeness and simplicity of the indicators system, and is more in line with the actual situation in the field. These results can provide a simpler and more convenient system for optimizing indicators for the study of evaluation indicators used to analyze irrigation water use efficiency.


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