ID 11626
JaLCDOI
Sort Key
16
FullText URL
Author
Ndegwa George Maina
Yomota, Atsushi
Abstract
Actual irrigation situation in a typical upland irrigation district was estimated by the water balance method during the 1993 rainy and the 1994 dry year periods. Soil moisture conditions were analysed for cases where daily district water use was supplied to all the cropped upland farms, and to reduced irrigation area percentages. Consumptive use was obtained through monthly weighted crop coefficients used to reduce penman's potential evapotranspiration. The moisture budget was examined at three levels of total readily available moisture, TRAM, i.e., 20,30 and 40 mm; the effect of upward capillary rise was also considered. The results of this study indicated that the actual moisture conditions in upland irrigated farms is influenced by irrigation area, cropping pattern, stage of crop growth and upward capillary rise in the farms. Actual irrigated area was within the range of about 44 to 100% of cropped area while upward capillary rise was between 0.1 and 1 mm day-1, TRAM level of 30 to 40 mm was considered most appropriate for the district. Monthly effective rainfall percentages from the water balance method were fairly close to that determined by the basic irrigation requirement method for some months. Basic irrigation requirement may therefore be considered to incorporate capillary water contribution.
Keywords
Upland irrigation
TRAM
Water balance
Capillary water
Effective rainfall
Publication Title
岡山大学環境理工学部研究報告
Published Date
1996-03
Volume
volume1
Issue
issue1
Publisher
岡山大学環境理工学部
Publisher Alternative
Faculty of Environmental Science and Technology, Okayama University
Start Page
151
End Page
162
ISSN
1341-9099
NCID
AN10529213
Content Type
Departmental Bulletin Paper
OAI-PMH Set
岡山大学
language
英語
File Version
publisher
NAID
Eprints Journal Name
fest