CALIBRATION AND VALIDATION OF FAO-AQUACROP MODEL FOR IRRIGATED AND WATER DEFICIENT BAMBARA GROUNDNUT

2011 ◽  
Vol 47 (3) ◽  
pp. 509-527 ◽  
Author(s):  
A. S. KARUNARATNE ◽  
S. N. AZAM-ALI ◽  
G. IZZI ◽  
P. STEDUTO
Keyword(s):  
Field Experiments ◽  
Water Productivity ◽  
Canopy Cover ◽  
Research Unit ◽  
Bambara Groundnut ◽  
Women Farmers ◽  
Sub Saharan Africa ◽  
Yield Response ◽  
Grain Legume ◽  
Aquacrop Model

SUMMARYSimulation of yield response to water plays an increasingly important role in optimization of crop water productivity (WP) especially in prevalent drought in Africa. The present study is focused on a representative crop: bambara groundnut (Vigna subterranea), an ancient grain legume grown, cooked, processed and traded mainly by subsistence women farmers in sub-Saharan Africa. Over four years (2002, 2006–2008), glasshouse experiments were conducted at the Tropical Crops Research Unit, University of Nottingham, UK under controlled environments with different landraces, temperatures (23 ± 5 °C, 28 ± 5 °C, 33 ± 5 °C) and soil moisture regimes (irrigated, early drought, late drought). Parallel to this, field experiments were conducted in Swaziland (2002/2003) and Botswana (2007/2008). Crop measurements of canopy cover (CC), biomass (B) and pod yield (Y) of selected experiments from glasshouse (2006 and 2007) and field (Botswana) were used to calibrate the FAO AquaCrop model. Subsequently, the model was validated against independent data sets from glasshouse (2002 and 2008) and field (Swaziland) for different landraces. AquaCrop simulations for CC, B and Y of different bambara groundnut landraces are in good agreement with observed data with R2 (CC-0.88; B-0.78; Y-0.72), but with significant underestimation for some landraces.

scholarly journals A semi-quantitative approach for modelling crop response to soil fertility: evaluation of the AquaCrop procedure

2014 ◽  
Vol 153 (7) ◽  
pp. 1218-1233 ◽  
Author(s):  
H. VAN GAELEN ◽  
A. TSEGAY ◽  
N. DELBECQUE ◽  
N. SHRESTHA ◽  
M. GARCIA ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Grain Yield ◽  
Soil Water ◽  
Crop Production ◽  
Water Productivity ◽  
Canopy Cover ◽  
Quantitative Approach ◽  
Fertility Level ◽  
Crop Response ◽  
Aquacrop Model

SUMMARYMost crop models make use of a nutrient-balance approach for modelling crop response to soil fertility. To counter the vast input data requirements that are typical of these models, the crop water productivity model AquaCrop adopts a semi-quantitative approach. Instead of providing nutrient levels, users of the model provide the soil fertility level as a model input. This level is expressed in terms of the expected impact on crop biomass production, which can be observed in the field or obtained from statistics of agricultural production. The present study is the first to describe extensively, and to calibrate and evaluate, the semi-quantitative approach of the AquaCrop model, which simulates the effect of soil fertility stress on crop production as a combination of slower canopy expansion, reduced maximum canopy cover, early decline in canopy cover and lower biomass water productivity. AquaCrop's fertility response algorithms are evaluated here against field experiments with tef (Eragrostis tef (Zucc.) Trotter) in Ethiopia, with maize (Zea mays L.) and wheat (Triticum aestivum L.) in Nepal, and with quinoa (Chenopodium quinoa Willd.) in Bolivia. It is demonstrated that AquaCrop is able to simulate the soil water content in the root zone, and the crop's canopy development, dry above-ground biomass development, final biomass and grain yield, under different soil fertility levels, for all four crops. Under combined soil water stress and soil fertility stress, the model predicts final grain yield with a relative root-mean-square error of only 11–13% for maize, wheat and quinoa, and 34% for tef. The present study shows that the semi-quantitative soil fertility approach of the AquaCrop model performs well and that the model can be applied, after case-specific calibration, to the simulation of crop production under different levels of soil fertility stress for various environmental conditions, without requiring detailed field observations on soil nutrient content.

scholarly journals Effect of Pterocladia capillacea Seaweed Extracts on Growth Parameters and Biochemical Constituents of Jew’s Mallow

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 420 ◽  
Author(s):  
Mohamed Ashour ◽  
Ahmed A. El-Shafei ◽  
Hanan M. Khairy ◽  
Doaa Y. Abd-Elkader ◽  
Mohamed A. Mattar ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Field Experiments ◽  
Growth Parameters ◽  
Water Productivity ◽  
Growth Yield ◽  
Irrigation Scheduling ◽  
Water Extraction ◽  
Yield Response ◽  
Yield Reduction ◽  
Initial Growth

We performed field experiments to evaluate the influence of two extraction treatments, seaweed (Pterocladia capillacea S.G. Gmelin) water extraction (WE) and ultrasound-assisted water extraction (USWE) at three concentrations (5%, 10%, and 15%), as well as control NPK traditional mineral fertilizer on the growth, yield, minerals, and antioxidants of Jew’s Mallow (Corchorus olitorius L.) during the two seasons of 2016 and 2017 in Egypt. Plant height, number of leaves, and fresh weight of WE10 treatment were the highest (p < 0.05) as 59.67 cm, 10.67 and 2.41 kg m−2 in 2016, respectively, and 57.33 cm, 11.00 and 2.32 kg m−2 in 2017, respectively. WE10 and USWE5 treatments produced the highest dry matter (17.07%) in 2016 and (16.97%) in 2017, respectively. WE10 plants had an increased water productivity of 41.2% relative to control plants in both seasons. The highest chlorophyll ‘a’ was recorded after the WE10 treatment in 2016 and 2017 (17.79 μg g−1 and 17.84 μg g−1, respectively). The highest levels of total antioxidant capacity, total phenolics, and total flavonoids were also recorded after the WE10 treatment. Application of WE10 boosted growth, yield, minerals, and antioxidants of Jew’s Mallow. The CROPWAT model was used to estimate the evapotranspiration, irrigation water requirements, and yield response to irrigation scheduling. Our data showed a yield reduction in the initial growth stage if a limited amount of water was provided. Therefore, irrigation water should be provided during the most important stages of crop development with the choice of effective irrigation practices to avoid water losses, as this helps to maximize yield.

Modeling effects of plastic mulching on crop yields and water productivity in the middle Heihe River Basin

2020 ◽  
Author(s):  
Wang Zhang ◽  
Chunmiao Zheng
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Global Sensitivity Analysis ◽  
Water Productivity ◽  
Regional Scale ◽  
Canopy Cover ◽  
Heihe River ◽  
Aquacrop Model ◽  
Plastic Mulching

&lt;p&gt;Plastic mulching is an effective field practice to improve crop water productivity (WP), especially widely used in arid and semi-arid areas. The positive effects of soil mulching on crop yield and WP have been studied through numerous field experiments and simulations at the site scale. However, few studies have focused on the mulching effects at the regional scale. Zhangye oasis, a typical arid region in the middle Heihe River Basin, was chosen as the study area. Global sensitivity analysis was applied to determine the most sensitive parameters in AquaCrop model. Based on the results of global sensitivity analysis, soil and crop parameters of AquaCrop model were calibrated and validated using field observations from three stations. The normalized root mean square error (NRMSE) values for soil water content, seed maize canopy cover, aboveground biomass, yield, spring wheat canopy cover, aboveground biomass and yield were 18.7%, 6.7%, 23.5%, 12.5%, 10.7%, 24.2% and 15.0% during the calibration period, and the corresponding values during the validation period were 25.1%, 7.0%, 22.2%, 17.7%, 9.1%, 23.6% and 11.7%, respectively. These values indicated the calibrated model performed well to simulate the soil water content and crop growth. Compared with no-mulching, the average soil water content during the growth period, seed maize yield and WP under mulching had been increased by 8.8%, 3.0% and 3.0%, respectively. The results demonstrated that plastic mulching could effectively improve the yield and WP of seed maize, which not significantly on spring wheat. This study offers a quantitatively analysis for plastic mulching applications at the regional scale.&lt;/p&gt;

scholarly journals Bambara Groundnut (Vigna subterranea [L.] Verdc.) Production, Utilisation and Genetic Improvement in Sub-Saharan Africa

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1345
Author(s):  
Nomathemba Gloria Majola ◽  
Abe Shegro Gerrano ◽  
Hussein Shimelis
Keyword(s):  
Nutritional Quality ◽  
Genetic Improvement ◽  
Market Access ◽  
Crop Management ◽  
Bambara Groundnut ◽  
Sub Saharan Africa ◽  
High Yield ◽  
Grain Legume ◽  
Vigna Subterranea ◽  
Sub Saharan

Bambara groundnut (Vigna subterranea [L.] Verdc.) is a nutritionally rich grain legume crop indigenous to Africa. It is tolerant to drought stress and has become adapted to grow under low input and marginal agricultural production systems in Africa and Asia. Bambara groundnut is an orphan crop, and represents a neglected and under researched plant genetic resource. Modern crop management, production technologies, and value chains are yet to be developed in Africa to achieve the potential economic gains from Bambara groundnut production and marketing. In sub-Saharan Africa (SSA) the production and productivity of Bambara groundnut is low and stagnant because of diverse abiotic and biotic stresses and socio-economic constraints. Improved crop management and post handling technologies, modern varieties with high yield and nutritional quality, value addition, and market access are among the key considerations in current and future Bambara groundnut research and development programs. This paper presents progress on Bambara groundnut production, utilization, and genetic improvement in SSA. It presents the key production constraints, genetic resources and analysis, breeding methods and genetic gains on yield, and nutritional quality and outlook. The information presented will guide the sustainable production and effective breeding of the crop in order to pursue food and nutrition security, and improve livelihoods through Bambara groundnut enterprises.

Evaluation of the FAO Aqua-Crop model for Durum wheat (Triticum durum Desf.)on the eastern Algeria under semi-arid conditions

2017 ◽  
Vol 51 (04) ◽  
Author(s):  
Guendouz Ali ◽  
Maamri Khalifa ◽  
Moumeni Lyes ◽  
Hafsi Miloud
Keyword(s):  
Water Stress ◽  
Durum Wheat ◽  
Field Experiments ◽  
Water Productivity ◽  
Relative Yield ◽  
Crop Model ◽  
Maturity Stage ◽  
Management Options ◽  
Aquacrop Model ◽  
Cropping Seasons

The relative yield decline that is expected under specific levels of water stress at different moments in the growing period is estimated by integrating the FAO Ky approach in the soil water balance model BUDGET. FAO recently developed a water-driven model (Aqua-Crop) for use as a decision support tool in planning and scenario analysis in different seasons and locations. The Aqua Crop model was evaluated with experimental data collected during three cropping seasons; the field experiments were conducted in Setif, Algeria. The objective of the study is to quantify the water stress based on estimation of evapo-transpiration by Aqua Crop model in Durum wheat under stressed conditions.The results of this study proved the efficiency of the Aqua Crop model to quantify the water stress. Total water stress during three cropping seasons (2010-2013) ranged between 0.15 (15%) at Double ridges to anthesis stage to 0.56 (56%) at Anthesis to maturity stage. The AquaCrop model can adequately quantify water stress and can be used to explore management options to improve wheat water productivity.

INFLUENCE OF SOWING DATE AND ENVIRONMENTAL FACTORS ON THE DEVELOPMENT AND YIELD OF BAMBARA GROUNDNUT (VIGNA SUBTERRANEA) LANDRACES IN A SUB-TROPICAL REGION

2008 ◽  
Vol 44 (2) ◽  
pp. 167-183 ◽  
Author(s):  
A. SESAY ◽  
C. N. MAGAGULA ◽  
A. B. MANSUETUS
Keyword(s):  
Environmental Factors ◽  
Rural Areas ◽  
Field Experiments ◽  
Sowing Date ◽  
Bambara Groundnut ◽  
Effect Of Temperature ◽  
Grain Legume ◽  
Tropical Region ◽  
Vigna Subterranea ◽  
Legume Crop

SUMMARYBambara groundnut (Vigna subterranea) is a grain legume crop, which is increasingly popular as food in rural areas across the African continent. However, reliable information pertaining to management of the crop is limited. Field experiments were conducted in Swaziland in the 1998/99 and 1999/2000 cropping seasons to determine the influence of sowing date and environmental factors on the growth, development and yield of bambara groundnut. In the 1998/99 season, seeds of one local landrace were sown on six dates between mid-September 1998 and mid-February 1999. In 1999/2000, seeds of two local landraces were sown on six dates between mid-October 1999 and late January 2000. The highest pod yield and total dry matter production were achieved in November sowings, with maximum pod yields of 1.3 and 0.64 t ha−1 for the 1998/99 and 1999/2000 seasons, respectively. Earlier sowing and successive delays in sowing from November caused substantial yield declines of as much as 72–75%. Sowing date influenced yields of bambara groundnut through the effect of temperature and daylength on plant development. For the landraces used in the study, while the rate of progress from sowing to flowering was influenced by temperature, the rate of progress from flowering to podding was influenced largely by daylength. The practical implications of the results for increased bambara groundnut production are discussed.

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 Rhizobium inoculants suppress emergence of the weed Striga gesnerioides in cowpea

2021 ◽  
Author(s):  
WAJIHA ABDULLAHI MU'AZ ◽  
Mahamdi Dianda ◽  
Ousmane Boukar ◽  
Ibnou Dieng ◽  
Gaya S Mohammed ◽  
...  
Keyword(s):  
Smallholder Farmers ◽  
Sub Saharan Africa ◽  
Yield Response ◽  
Grain Legume ◽  
Striga Gesnerioides ◽  
Rhizobium Inoculation ◽  
Resistant Varieties ◽  
Sub Saharan ◽  
The Impact ◽  
Resistant Genotypes

Abstract Cowpea is a grain legume of major importance in sub-Saharan Africa where it is cultivated by smallholder farmers on poor soils and production is often constrained by the parasitic weed Striga gesnerioides. Experiments were conducted to assess the potential of rhizobium inoculation in mitigating Striga infestation and increasing cowpea productivity. We tested under basal P application and artificial S. gesnerioides inoculation the impact of cowpea genotypes (G) (nine Striga-resistant and 11 Striga–susceptible genotypes) and bradyrhizobium inoculation (N) (two bradyrhizobium strains USDA3384 and IRJ2180A, and uninoculated control) on Striga dynamics and cowpea yield. Additional treatments included N supplied as urea (with and without), and no input (i.e., soil inherent N and P) that served as negative check. A first experiment was carried out in potted sterile soils in the screen house excluding addition of N-fertilizers. Significant G x N interactions were observed in counts of nodule (P = 0.012), Striga attachment (P < 0.0001) and emergence (P = 0.005), and cowpea shoot growth (P = 0.016). Cowpea nodulated poorly across host lines, Striga counts were the lowest for resistant varieties with no emerged plants. Rhizobial inoculants depressed Striga counts with consistent differences found across cowpea genotypes. Inoculation with IRJ2180A performed the best against Striga attachment in resistant genotypes, and its emergence in susceptible genotypes. In the field trial, nodule numbers were lowest in cowpea without inputs (P < 0.0001). The G x N interaction was significant in emerged Striga plants (P < 0.0001). Resistant genotypes were free of emerged Striga while for susceptible ones, Striga emergence was the highest without any input addition. Significant G x N interaction was observed in cowpea grain yield (P < 0.0001). Yield response to inoculation was most obvious for resistant genotypes inoculated with the strain IRJ2180A (P = 0.0043). The integrated use of Striga-resistant cowpea lines and elite bradyrhizobium inoculant under moderate application of P-based fertilizer could be a promising approach for mitigating Striga infestation and increasing productivity.

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