scholarly journals Crop Evapotranspiration

Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 614 ◽  
Author(s):  
Ray Anderson ◽  
Andrew French

Evapotranspiration (ET) is one of the largest components of the water cycle, and accurately measuring and modeling ET is critical for improving and optimizing agricultural water management. However, parameterizing ET in croplands can be challenging due to the wide variety of irrigation strategies and techniques, crop varieties, and management approaches that employ traditional tabular ET and make crop coefficient approaches obsolete. This special issue of Agronomy highlights nine approaches to improve the measurement and modeling of ET across a range of spatial and temporal resolutions and differing environments that address some of the challenges encountered.

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Songhao Shang

Crop water requirement is essential for agricultural water management, which is usually available for crop growing stages. However, crop water requirement values of monthly or weekly scales are more useful for water management. A method was proposed to downscale crop coefficient and water requirement from growing stage to substage scales, which is based on the interpolation of accumulated crop and reference evapotranspiration calculated from their values in growing stages. The proposed method was compared with two straightforward methods, that is, direct interpolation of crop evapotranspiration and crop coefficient by assuming that stage average values occurred in the middle of the stage. These methods were tested with a simulated daily crop evapotranspiration series. Results indicate that the proposed method is more reliable, showing that the downscaled crop evapotranspiration series is very close to the simulated ones.


Author(s):  
P. Glitse ◽  
B. V. Nyamadi ◽  
K. W. Darkwah ◽  
K. A. Mintah

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.


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