Validation of Aquacrop for Different Irrigation Regimes of Onion (Allium Cepa) in Bontanga Irrigation Scheme

2018 ◽  
Vol 1 (1) ◽  
pp. 1-12
Author(s):  
Y. K. Agbemabiese ◽  
A-G Shaibu ◽  
V. D. Gbedzi
Keyword(s):  
Allium Cepa ◽  
Crop Yield ◽  
Water Productivity ◽  
Leaf Biomass ◽  
Crop Water ◽  
Irrigation Scheme ◽  
Crop Water Productivity ◽  
Irrigation Regimes ◽  
Aquacrop Model ◽  
Mean Square Errors

Crop water productivity models are important tools in evaluating the effect of different irrigation regime on crop yield. AquaCrop model is a crop water productivity model adopted by the Land and Water Division of FAO in the year 2009. It simulates yield response to water for herbaceous crops, and it is particularly suitable in addressing conditions where water is a key limiting factor in crop production such as in northern Ghana. The objective of this study was to calibrate the AquaCrop model for different irrigation regimes for onion (Allium cepa), to determine its effect on crop growth and yield parameters of the crop at the Bontanga irrigation scheme. To achieve these, the Randomised Complete Block Design (RCBD) was used on Red Creole onion variety. RCBD was made up of four irrigation treatment regimes, 117%, 100%, 80% and 60% crop water requirements (CWR) of onion, with five replicates. Results indicated that there was no significant variation in yield, dry bulb biomass and total biomass, but there was difference for dry leaf biomass of onion at 0.05 significance level. The AquaCrop model simulated satisfactorily the crop yield, biomass and evapotranspiration water productivity of onion. There was a strong correlation and a significant linear relation between the simulated and measured crop yield, biomass and evapotranspiration water productivity. Validation of AquaCrop model using Nash-Sutcliffe efficiency (E), Root mean square errors (RMSE) and index of agreement (d) showed that, AquaCrop model can be used to simulate CWR of bulb crops, such as onion.

scholarly journals Maize Seedling Establishment, Grain Yield and Crop Water Productivity Response to Seed Priming and Irrigation Management in a Mediterranean Arid Environment

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 756
Author(s):  
AbdAllah M. El-Sanatawy ◽  
Ahmed S. M. El-Kholy ◽  
Mohamed M. A. Ali ◽  
Mohamed F. Awad ◽  
Elsayed Mansour
Keyword(s):  
Grain Yield ◽  
Deficit Irrigation ◽  
Water Productivity ◽  
Irrigation Management ◽  
Seed Priming ◽  
Severe Drought ◽  
Arid Environments ◽  
Crop Water ◽  
Crop Water Productivity ◽  
Irrigation Regimes

Water shortage is a major environmental stress that destructively impacts maize production, particularly in arid regions. Therefore, improving irrigation management and increasing productivity per unit of water applied are needed, especially under the rising temperature and precipitation fluctuations induced by climate change. Laboratory and field trials were carried out in the present study, which were aimed at assessing the possibility of promoting maize germination, growth, grain yield and crop water productivity (CWP) using seed priming under different irrigation regimes. Two seed priming treatments, i.e., hydro-priming and hardening versus unprimed seeds, were applied under four irrigation regimes, i.e., 120, 100, 80 and 60% of estimated crop evapotranspiration (ETc). The obtained results indicated that increasing irrigation water from 100% up to 120% ETc did not significantly increase grain yield or contributing traits, while it decreased CWP. Deficit irrigation of 80 and 60% ETc gradually decreased grain yield and all attributed traits. Seed priming significantly ameliorated seedlings’ vigor as indicated by earlier germination, higher germination percentage, longer roots and shoots, and heavier fresh and dry weight than unprimed seeds with the superiority of hardening treatment. Additionally, under field conditions, seed priming significantly increased grain yield, yield contributing traits and CWP compared with unprimed treatment. Interestingly, the results reflect the role of seed priming, particularly hardening, in mitigating negative impacts of drought stress and enhancing maize growth, grain yield and attributed traits as well as CWP under deficit irrigation conditions. This was demonstrated by a significant increase in grain yield and CWP under moderate drought and severe drought conditions compared with unprimed treatment. These results highlight that efficient irrigation management and seed priming can increase maize yield and water productivity in arid environments.

scholarly journals Drops for crops: modelling crop water productivity on a global scale

2013 ◽  
Vol 10 (3) ◽  
pp. 295-300
Keyword(s):  
Crop Yield ◽  
Food Policy ◽  
Water Productivity ◽  
Global Scale ◽  
Fertilizer Management ◽  
Crop Water ◽  
Crop Growth Model ◽  
Crop Water Productivity ◽  
Maize Yields ◽  
Good Agreement

There is an emerging need to support water and food policy and decision making at the global and national levels. A systematic tool that is capable of analyzing water-food relationships with high spatial resolutions would be very useful. A GEPIC model has recently been developed by integrating a crop growth model with a Geographic Information System (GIS). The GEPIC model was applied to simulate crop yield and crop water productivity (CWP) for maize at a spatial resolution of 30 arc-minutes on a global scale. A comparison between simulated yields and FAO statistical yields in 124 countries shows a good agreement. The simulated CWP values are mainly in line with the measured values reported in literature. The crop yield and CWP were simulated with the assumption of sufficient water and fertilizer supply, holding other factors unchanged. The simulation results show that many countries have the potentials in achieving high maize yields and CWP. More than 80% of African countries have the potential to double their CWP. This reflects the current poor water and fertilizer management there. The results imply that efforts have to be strengthened to improve water and fertilizer management should the malnutrition be reduced or even eliminated.

WATER AND NITROGEN-BALANCE AND -USE EFFICIENCY IN A RICE (ORYZA SATIVA)–WHEAT (TRITICUM AESTIVUM) CROPPING SYSTEM AS INFLUENCED BY MANAGEMENT INTERVENTIONS: FIELD AND SIMULATION STUDY

2011 ◽  
Vol 47 (4) ◽  
pp. 609-628 ◽  
Author(s):  
S. K. JALOTA ◽  
BHARAT BHUSHAN VASHISHT ◽  
HARSIMRAN KAUR ◽  
V. K. ARORA ◽  
K. K. VASHIST ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Field Experiments ◽  
Water Productivity ◽  
N Uptake ◽  
Water Evaporation ◽  
Fertilizer N ◽  
Crop Water ◽  
Management Interventions ◽  
Crop Water Productivity ◽  
Irrigation Regimes

SUMMARYThe present study concerns identification of the most profitable and water and nitrogen use efficient best management practice (BMP) in a rice–wheat system using a combined approach of field experimentation and simulation. In the field study, two independent experiments, (1) effect of three transplanting/sowing dates, two cultivars and two irrigation regimes and (2) effect of four nitrogen (N) levels with four irrigation regimes, were conducted for two seasons of 2008–09 and 2009–10 at Punjab Agricultural University, Ludhiana, India. Integrating the treatments of the two independent field experiments, simulations were run with the CropSyst model. The BMP demonstrated was transplanting of rice on 20 June and sowing of wheat on 5 November, irrigation to rice at 4-day drainage period and to wheat at irrigation water depth/Pan–E (open pan evaporation) ratio of 0.9, and fertilizer N of 150 kg ha−1 to each crop for medium-duration varieties. This practice gave higher profit (35%), equivalent rice yield (16%), crop water productivity (15%), irrigation water productivity (51%), economic water productivity (34%) and economic N productivity (94%) than the existing practice by the farmers. The improvement in crop water productivity by shifting the transplanting/sowing date was due to reduction in soil water evaporation and increased transpiration and fertilizer N productivity through increased N uptake.

scholarly journals Thermal imaging to assess the crop water status of melon plants under tropical semi-arid climate

2021 ◽  
Author(s):  
Márcio Facundo Aragão ◽  
Luis Gonzaga Pinheiro Neto ◽  
Thales Vinícius de Araújo Viana ◽  
Juan Manzano-Juarez ◽  
Claudivan Feitosa Lacerda ◽  
...  
Keyword(s):  
Crop Yield ◽  
Soil Cover ◽  
Water Status ◽  
Water Productivity ◽  
Irrigation Scheduling ◽  
Leaf Water ◽  
Crop Water ◽  
Thermal Images ◽  
Irrigation Regimes ◽  
Semi Arid

Abstract Deficit irrigation (DI) strategies and soil cover are highly effective to improve the the water productivity in semi-arid regions. However, the effective monitoring of plant water status under DI strategies becomes crucial. The main objective of this study was to evaluate the use of thermal images to estimate the water status of melon plants cultivated in soil with and without mulching under different irrigation regimes. The experience was carried out from October to December 2018. The study was carried out in a randomized block design, in a split plot arrangement. Plots were composed by soil cover (with and without mulching with plant material), and subplots by 5 irrigation regimes (120, 100, 80, 60 and 40% of crop evapotranspiration-ETc), with five replicates. The following variables were evaluated: canopy temperature (Tcanopy), leaf water potential (Ψleaf), air temperature (Tair), soil moisture, crop yield and the thermal index (ΔT), this being defined as the difference between Tcanopy and Tair. ΔT showed high correlations with crop yield and crop water consumption, evidencing that thermography is an efficient tool to identify the water status of melon plants and could be employed for a proper irrigation scheduling under the tropical semi-arid scenarios. Moreover, the use of thermal images also allowed the identification of beneficial effects of soil cover on leaf water status and crop yield, mainly under moderate DI. The obtained results also demonstrate that mulching is essential to increase melon yield and water productivity in tropical regions.

Climate change impacts on crop water productivity in Africa using a multi-model inter-comparison

2020 ◽  
Author(s):  
Imeshi Weerasinghe ◽  
Celray James Chawanda ◽  
Ann van Griensven
Keyword(s):  
Climate Change ◽  
Crop Yield ◽  
Crop Yields ◽  
Water Productivity ◽  
Baseline Scenario ◽  
Crop Water ◽  
Yield Data ◽  
Water Vapour Flux ◽  
Crop Models ◽  
Crop Water Productivity

<p>Evapotranspiration (ET) or the water vapour flux is an important component in the water cycle and is widely studied due to its implications in disciplines ranging from hydrology to agricultural and climate sciences. In the recent past, growing attention has been given to estimating ET fluxes at regional and global scales. However, estimation of ET at large scales has been a difficult task due to direct measurement of ET being possible only at point locations, for example using flux towers. For the African continent, only a limited number of flux tower data are openly available for use, which makes verification of regional and global ET products very difficult. Recent advances in satellite based products provide promising data to fill these observational gaps.</p><p>In this study we propose to investigate the Climate Change (CC) impact on crop water productivity across Africa using ET and crop yield predictions of different crop models for future climate scenarios. Different model outputs are evaluated including models from both the ISI-MIP 2a and 2b protocols. Considering the problem of direct observations of ET being difficult to obtain, especially over Africa, we use ET estimates from several remotely sensed derived products as a references to evaluate the crop models (maize) in terms of magnitude, spatial patterns and variations between models. The crop model results for crop yield are compared to FAO reported crop yields at country scale. The results show a very strong disagreement between the different crop models of the baseline scenario and when compared with ET and crop yield data.  Also, a very large uncertainty is obtained for the climate change predictions. It is hence recommended to improve the crop models for application in Africa.</p>

Simulation of crop production in weed-infested fields for data-scarce regions

2016 ◽  
Vol 154 (6) ◽  
pp. 1026-1039 ◽  
Author(s):  
H. VAN GAELEN ◽  
N. DELBECQUE ◽  
B. ABRHA ◽  
A. TSEGAY ◽  
D. RAES
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Productivity ◽  
Canopy Cover ◽  
Simple Approach ◽  
Crop Water ◽  
Crop Water Productivity ◽  
Aquacrop Model ◽  
Weed Infestation

SUMMARYWeed infestation is a major yield-reducing factor that also decreases crop water productivity. Yet weeds are often neglected in crop productivity simulation studies, because existing empirical equations and mechanistic models are not widely applicable or have a high demand for input data and calibration. For that reason, AquaCrop, a widely applicable crop water productivity model, was expanded with a weed management module which requires only two easily obtainable input variables: (i) relative leaf cover of weeds, and (ii) weed-induced increase of total canopy cover. Using these inputs, AquaCrop directly simulates soil water content, crop canopy development and production as it is observed in weed-infested fields. Despite this simple approach, AquaCrop performed well to simulate soil water content in the root zone (relative root-mean-square error (RRMSE) of 5–13%), canopy cover (RRMSE of 15–22%), dry above-ground crop biomass during the season (RRMSE of 21–39%) and at maturity (RRMSE of 5–6%) and yield (RRMSE of 11–25%) of barley and wheat grown under different weed infestation levels and environments. The current study illustrates that the AquaCrop model can be used to assess the effect of weed infestation on crop growth and production, using a simple approach that is applicable to diverse environmental and agronomic conditions, even in data-scarce regions.

scholarly journals Accessing future crop yield and crop water productivity over the Heihe River basin in northwest China under a changing climate

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Qi Liu ◽  
Jun Niu ◽  
Bellie Sivakumar ◽  
Risheng Ding ◽  
Sien Li
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Crop Yield ◽  
Water Productivity ◽  
Heihe River Basin ◽  
Future Climate Change ◽  
Heihe River ◽  
Crop Water ◽  
Crop Water Productivity ◽  
The Heihe River Basin

AbstractQuantitative evaluation of the response of crop yield and crop water productivity (CWP) to future climate change is important to prevent or mitigate the adverse effects of climate change. This study made such an evaluation for the agricultural land over the Heihe River basin in northwest China. The ability of 31 climate models for simulating the precipitation, maximum temperature, and minimum temperature was evaluated for the studied area, and a multi-model ensemble was employed. Using the previously well-established Soil and Water Assessment Tool (SWAT), crop yield and crop water productivity of four major crops (corn, wheat, barley, and spring canola-Polish) in the Heihe River basin were simulated for three future time periods (2025–2049, 2050–2074, and 2075–2099) under two Representative Concentration Pathways (RCP4.5 and RCP8.5). The results revealed that the impacts of future climate change on crop yield and CWP of wheat, barley, and canola would all be negative, whereas the impact on corn in the eastern part of the middle reaches of the Heihe River basin would be positive. On the whole, climate change under RCP8.5 scenario would be more harmful to crops, while the corn crops in the Minle and Shandan counties have better ability to cope with climate change.

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