scholarly journals Crop Modeling Applications in Agricultural Water Management

2017 ◽  
Vol 60 (6) ◽  
pp. 1959-1964 ◽  
Author(s):  
Isaya Kisekka ◽  
Kendall C. DeJonge ◽  
Liwang Ma ◽  
Joel Paz ◽  
Kyle Douglas-Mankin
Keyword(s):  
Water Management ◽  
Irrigation Management ◽  
Climate Impact ◽  
Irrigation Scheduling ◽  
Groundwater Depletion ◽  
Crop Modeling ◽  
Agricultural Water ◽  
Agricultural Water Management ◽  
Crop Models ◽  
Introductory Article

Abstract. This article introduces the fourteen articles that comprise the “Crop Modeling and Decision Support for Optimizing Use of Limited Water” collection. This collection was developed from a special session on crop modeling applications in agricultural water management held at the 2016 ASABE Annual International Meeting (AIM) in Orlando, Florida. In addition, other authors who were not able to attend the 2016 ASABE AIM were also invited to submit papers. The articles summarized in this introductory article demonstrate a wide array of applications in which crop models can be used to optimize agricultural water management. The following section titles indicate the topics covered in this collection: (1) evapotranspiration modeling (one article), (2) model development and parameterization (two articles), (3) application of crop models for irrigation scheduling (five articles), (4) coordinated water and nutrient management (one article), (5) soil water management (two articles), (6) risk assessment of water-limited irrigation management (one article), and (7) regional assessments of climate impact (two articles). Changing weather and climate, increasing population, and groundwater depletion will continue to stimulate innovations in agricultural water management, and crop models will play an important role in helping to optimize water use in agriculture. Keywords: Agricultural water management, Crop modeling, Evapotranspiration, Irrigation, Irrigation scheduling.

scholarly journals Effects of Surface Heterogeneity Due to Drip Irrigation on Scintillometer Estimates of Sensible, Latent Heat Fluxes and Evapotranspiration over Vineyards

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 81
Author(s):  
Hatim M. E. Geli ◽  
José González-Piqueras ◽  
Christopher M. U. Neale ◽  
Claudio Balbontín ◽  
Isidro Campos ◽  
...  
Keyword(s):  
Water Management ◽  
Soil Moisture ◽  
Surface Heterogeneity ◽  
Irrigation Scheduling ◽  
Heat Fluxes ◽  
Source Surface ◽  
Agricultural Water ◽  
Agricultural Water Management ◽  
Vegetation Growth ◽  
Growth Variability

Accurate estimates of sensible (H) and latent (LE) heat fluxes and actual evapotranspiration (ET) are required for monitoring vegetation growth and improved agricultural water management. A large aperture scintillometer (LAS) was used to provide these estimates with the objective of quantifying the effects of surface heterogeneity due to soil moisture and vegetation growth variability. The study was conducted over drip-irrigated vineyards located in a semi-arid region in Albacete, Spain during summer 2007. Surface heterogeneity was characterized by integrating eddy covariance (EC) observations of H, LE and ET; land surface temperature (LST) and normalized difference vegetation index (NDVI) data from Landsat and MODIS sensors; LST from an infrared thermometer (IRT); a data fusion model; and a two-source surface energy balance model. The EC observations showed 16% lack of closure during unstable atmospheric conditions and was corrected using the residual method. The comparison between the LAS and EC measurements of H, LE, and ET showed root mean square difference (RMSD) of 25 W m−2, 19 W m−2, and 0.41 mm day−1, respectively. LAS overestimated H and underestimated both LE and ET by 24 W m−2, 34 W m−2, and 0.36 mm day−1, respectively. The effects of soil moisture on LAS measurement of H was evaluated using the Bowen ratio, β. Discrepancies between HLAS and HEC were higher at β ≤ 0.5 but improved at 1 ≥ β > 0.5 and β > 1.0 with R2 of 0.76, 0.78, and 0.82, respectively. Variable vineyard growth affected LAS performance as its footprints saw lower NDVILAS compared to that of the EC (NDVIEC) by ~0.022. Surface heterogeneity increased during wetter periods, as characterized by the LST–NDVI space and temperature vegetation dryness index (TVDI). As TVDI increased (decreased) during drier (wetter) conditions, the discrepancies between HLAS and HEC, as well as LELAS and LEEC Re decreased (increased). Thresholds of TVDI of 0.3, 0.25, and 0.5 were identified, above which better agreements between LAS and EC estimates of H, LE, and ET, respectively, were obtained. These findings highlight the effectiveness and ability of LAS in monitoring vegetation growth over heterogonous areas with variable soil moisture, its potential use in supporting irrigation scheduling and agricultural water management over large regions.

The State of Irrigation Infrastructure in Ghana: The Way Forward

2018 ◽  
Vol 1 (1) ◽  
pp. 54-67
Author(s):  
P. Glitse ◽  
B. V. Nyamadi ◽  
K. W. Darkwah ◽  
K. A. Mintah
Keyword(s):  
Water Management ◽  
Large Scale ◽  
Irrigated Agriculture ◽  
Energy Access ◽  
Agricultural Water ◽  
Agricultural Water Management ◽  
Irrigation Development ◽  
Factors Affecting ◽  
Cost Of Energy ◽  
Irrigation Infrastructure

The Ghana Irrigation Development Authority (GIDA) is a public sector organization established to promote agricultural growth through the provision of irrigation infrastructure and other agricultural water management techniques. Irrigated agriculture in Ghana is categorized into formal, informal or smallholder and large-scale commercial irrigation. Over the years, irrigation development in the country has been faced with a number of challenges, which necessitated the development of the National Irrigation Policy, Strategies and Regulatory Measures and the Ghana Agricultural Water Management Pre-Investment Reform Action Framework. A number of factors affecting irrigation development in the country include lack of capital, commitment by successive governments, cost of energy, access to land and credit, lack of technical know-how and encroachment, among others. Analysis of budget provided by government for public irrigation development was carried out using simple linear regression. Results indicate a bright prospect of irrigation development, with reforms under implementation. A minimum of GHS 633.43 million is required for release into the sub-sector by government together with investments from private sector in the next ten years to shift the balance towards positive growth. To solve the problem of inadequate funding of the sub-sector activities, it is recommended that the GIDA collaborates with Development Partners to fund projects and activities in line with their objectives. GIDA should develop effective programmes for building capacity of contractors involved in development of infrastructure. GIDA should deepen its collaboration with private investors under PPPs and convert electric and diesel/petrol powered irrigation pumps to solar powered ones.

Sign in / Sign up

Export Citation Format

Share Document