scholarly journals CROPGRO-Soybean Model Calibration and Assessment of Soybean Yield Responses to Climate Change

2020 ◽  
Vol 09 (03) ◽  
pp. 297-316
Author(s):  
Joseph E. Quansah ◽  
Pauline Welikhe ◽  
Gamal El Afandi ◽  
Souleymane Fall ◽  
Desmond Mortley ◽  
...  
Keyword(s):  
Climate Change ◽  
Model Calibration ◽  
Soybean Yield ◽  
Yield Responses

scholarly journals Modelling soybean yield responses to seeding date under projected climate change scenarios

2017 ◽  
Author(s):  
Qi Jing ◽  
Ted Huffman ◽  
Jiali Shang ◽  
Jiangui Liu ◽  
Elizabeth Pattey ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Change Scenarios ◽  
Soybean Yield ◽  
Seeding Date ◽  
Yield Responses

scholarly journals The Genotypic and Phenotypic Basis of Chickpea (Cicer arietinum L.) Cultivars for Irrigation-Based Production in Ethiopia

2017 ◽  
Vol 9 (8) ◽  
pp. 229 ◽  
Author(s):  
Nigusie Girma ◽  
Asnake Fikre ◽  
Chris O. Ojiewo
Keyword(s):  
Climate Change ◽  
Seed Weight ◽  
Growing Season ◽  
Moisture Stress ◽  
Cicer Arietinum L ◽  
Research And Innovation ◽  
Complementary Role ◽  
Alternative Approach ◽  
Yield Responses ◽  
100 Seed Weight

Development of irrigation-based chickpea production is considered the most important alternative approach in combating climate change and maximizing productivity, especially in moisture-stress areas and in areas where water and land for irrigation is available. In central Ethiopia, where production of chickpea (especially Kabuli type) is becoming an important part of agriculture, although many superior varieties (both desi and Kabuli types) are available, they have been evaluated and released based on rainfed production. Hence, there is an urgent need for evaluation of varieties suited for irrigation-based production. Towards this goal, during the 2012/13 growing season, 14 Kabuli genotypes (previously introduced) and 24 desi genotypes (nurseries obtained from ICRISAT) were evaluated independently at three and one locations respectively (Kabuli at Debre Zeit, Ambo and Werer; desi at Debre Zeit) for production adaptation under irrigation. The parameters evaluated were date of maturity, 100-seed weight and yield. Overall, while most Kabuli genotypes showed high adaptability to irrigation-based production at all locations, four Kabuli genotypes (X96TH-52-14/2000 = 106.7DAS, FLIP-02-39C = 107DAS, X98TH-51-1-3 = 107.9DAS and ICCV-07313 = 107DAS) were found to be earlier in maturity; two genotypes (ICCV-07313 = 42.5 g and ICCV-04305 = 37.8 g) were identified as having high 100-seed weight and one genotype (ICCV-05309 = 3228.8 kg/ha or 32 quintals/ha) out yielded all genotypes across locations. The result of combined analysis indicated five promising genotypes showing more than 20 kg/ha yield on average. All desi varieties showed maturity dates of under four months; six genotypes showed higher 100-seed weight and eight genotypes showed promising yield responses (> 2000 kg/ha). From these preliminary results, it can be deduced that irrigation can play a significantly complementary role to the rainfed system, provided the genetics by management is optimized through research and innovation.

scholarly journals Effects of model calibration on hydrological and water resources management simulations under climate change in a semi-arid watershed

2020 ◽  
Vol 163 (3) ◽  
pp. 1247-1266 ◽  
Author(s):  
Hagen Koch ◽  
Ana Lígia Chaves Silva ◽  
Stefan Liersch ◽  
José Roberto Gonçalves de Azevedo ◽  
Fred Fokko Hattermann
Keyword(s):  
Climate Change ◽  
Water Management ◽  
Water Resources ◽  
Water Resources Management ◽  
Model Calibration ◽  
Arid Regions ◽  
Discharge Data ◽  
Resources Management ◽  
North Eastern ◽  
Semi Arid

AbstractSemi-arid regions are known for erratic precipitation patterns with significant effects on the hydrological cycle and water resources availability. High temporal and spatial variation in precipitation causes large variability in runoff over short durations. Due to low soil water storage capacity, base flow is often missing and rivers fall dry for long periods. Because of its climatic characteristics, the semi-arid north-eastern region of Brazil is prone to droughts. To counter these, reservoirs were built to ensure water supply during dry months. This paper describes problems and solutions when calibrating and validating the eco-hydrological model SWIM for semi-arid regions on the example of the Pajeú watershed in north-eastern Brazil. The model was calibrated to river discharge data before the year 1983, with no or little effects of water management, applying a simple and an enhanced approach. Uncertainties result mainly from the meteorological data and observed river discharges. After model calibration water management was included in the simulations. Observed and simulated reservoir volumes and river discharges are compared. The calibrated and validated models were used to simulate the impacts of climate change on hydrological processes and water resources management using data of two representative concentration pathways (RCP) and five earth system models (ESM). The differences in changes in natural and managed mean discharges are negligible (< 5%) under RCP8.5 but notable (> 5%) under RCP2.6 for the ESM ensemble mean. In semi-arid catchments, the enhanced approach should be preferred, because in addition to discharge, a second variable, here evapotranspiration, is considered for model validation.

The challenges and opportunities for wheat production under future climate in Northern Ethiopia

2016 ◽  
Vol 155 (3) ◽  
pp. 379-393 ◽  
Author(s):  
A. ARAYA ◽  
I. KISEKKA ◽  
A. GIRMA ◽  
K. M. HADGU ◽  
F. N. TEGEBU ◽  
...  
Keyword(s):  
Climate Change ◽  
Model Calibration ◽  
Wheat Yield ◽  
Planting Date ◽  
N Fertilizer ◽  
Future Climate ◽  
Northern Ethiopia ◽  
Short Term ◽  
Adaptation Practices ◽  
Impacts Of Climate Change

SUMMARYWheat is an important crop in the highlands of Northern Ethiopia and climate change is expected to be a major threat to wheat productivity. However, the potential impacts of climate change and adaptation on wheat yield has not been documented for this region. Wheat field experiments were carried out during the 2011–2013 cropping seasons in Northern Ethiopia to: (1) calibrate and evaluate Agricultural Production Systems sIMulator (APSIM)-wheat model for exploring the impacts of climate change and adaptation on wheat yield; (2) explore the response of wheat cultivar/s to possible change in climate and carbon dioxide (CO2) under optimal and sub-optimal fertilizer application and (3) assess the impact of climate change and adaptation practices on wheat yield based on integration of surveyed field data with climate simulations using multi-global climate models (GCMs; for short- and mid-term periods) for the Hintalo-Wajrat areas of Northern Ethiopia. The treatments were two levels of fertilizer (optimal and zero fertilization); treatments were replicated three times and arranged in a randomized complete block design. All required information for model calibration and evaluation were gathered from experimental studies. In addition, a household survey was conducted in 2012 in Northern Ethiopia. Following model calibration and performance testing, response of wheat to various nitrogen (N) fertilizer rates, planting date, temperature and combinations of other climate variables and CO2 were assessed. Crop simulations were conducted with future climate scenarios using 20 different GCMs and compared with a baseline. In addition, simulations were carried out using climate data from five different GCM with and without climate change adaptation practices. The simulated yield showed clear responses to changes in temperature, N fertilizer and CO2. Regardless of choice of cultivar, increasing temperatures alone (by up to 5 °C compared with the baseline) resulted in reduced yield while the addition of other factors (optimal fertilizer with elevated CO2) resulted in increased yield. Considering optimal fertilizer (64 kg/ha N) as an adaptation practice, wheat yield in the short-term (2010–2039) and mid-term (2040–2069) may increase at least by 40%, compared with sub-optimal N levels. Assuming CO2 and present wheat management is unchanged, simulation results based on 20 GCMs showed that median wheat yields will reduce by 10% in the short term and by 11% in the mid-term relative to the baseline data, whereas under changed CO2 with present management, wheat yield will increase slightly, by up to 8% in the short term and by up to 11% in the mid-term period, respectively. Wheat yield will substantially increase, by more than 100%, when simulated based on combined use of optimal planting date and fertilizer applications. Increased temperature in future scenarios will cause yield to decline, whereas CO2 is expected to have positive impacts on wheat yield.

scholarly journals Effect of Septoria brown spot on soybean yield in Illinois

2019 ◽  
Author(s):  
Heng-An Lin ◽  
María B. Villamil ◽  
Santiago X. Mideros
Keyword(s):  
Disease Severity ◽  
Critical Factor ◽  
Brown Spot ◽  
Linear Predictor ◽  
Soybean Yield ◽  
Best Linear Predictor ◽  
Effect On Yield ◽  
Yield Responses ◽  
Production Areas ◽  
Different Levels

AbstractBrown spot caused by Septoria glycines is a prevalent foliar disease in all soybean production areas. Application of foliar fungicides after bloom reduces the disease severity, yet yield responses are not consistent among locations and years. Our research goal was to determine the effect of different levels of Septoria brown spot on yield. Different levels of disease severity were effectively obtained in the field by weekly application of chlorothalonil for three, six, and nine times after disease inoculation at V3/V4 stage. Fungicide treatments had a significant effect on vertical progress and chlorotic area with no statistically significant effect on yield. Soybean yield was negatively correlated with vertical progress of the disease (r = −0.36). The vertical progress was the best linear predictor of yield. Based on this model, when the vertical progress of brown spot at R6 increased by 10%, the yield decreased by 142.13 kg/ha (3.4%). A variance component analyses of our data showed that location was the most critical factor, illustrating the significant effect of local environmental conditions on the disease. Power analyses indicated that at least eight locations are needed to detect an effect of 269 kg/ha. Our results provide useful information to improve the experimental design for future experiments addressing the yield constrain by late season diseases of soybean.

scholarly journals Comparison of two model calibration approaches and their influence on future projections under climate change in the Upper Indus Basin

2020 ◽  
Vol 163 (3) ◽  
pp. 1227-1246 ◽  
Author(s):  
Muhammad Fraz Ismail ◽  
Bibi S. Naz ◽  
Michel Wortmann ◽  
Markus Disse ◽  
Laura C. Bowling ◽  
...  
Keyword(s):  
Climate Change ◽  
Model Calibration ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Indus Basin ◽  
Glacier Mass Balance ◽  
Infiltration Capacity ◽  
Upper Indus Basin ◽  
Calibration Approach

AbstractThis study performs a comparison of two model calibration/validation approaches and their influence on future hydrological projections under climate change by employing two climate scenarios (RCP2.6 and 8.5) projected by four global climate models. Two hydrological models (HMs), snowmelt runoff model + glaciers and variable infiltration capacity model coupled with a glacier model, were used to simulate streamflow in the highly snow and glacier melt–driven Upper Indus Basin. In the first (conventional) calibration approach, the models were calibrated only at the basin outlet, while in the second (enhanced) approach intermediate gauges, different climate conditions and glacier mass balance were considered. Using the conventional and enhanced calibration approaches, the monthly Nash-Sutcliffe Efficiency (NSE) for both HMs ranged from 0.71 to 0.93 and 0.79 to 0.90 in the calibration, while 0.57–0.92 and 0.54–0.83 in the validation periods, respectively. For the future impact assessment, comparison of differences based on the two calibration/validation methods at the annual scale (i.e. 2011–2099) shows small to moderate differences of up to 10%, whereas differences at the monthly scale reached up to 19% in the cold months (i.e. October–March) for the far future period. Comparison of sources of uncertainty using analysis of variance showed that the contribution of HM parameter uncertainty to the overall uncertainty is becoming very small by the end of the century using the enhanced approach. This indicates that enhanced approach could potentially help to reduce uncertainties in the hydrological projections when compared to the conventional calibration approach.

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