Comparison of ET measured with neutron moisture meters and weighing lysimeters

Wright, James L. (1990) Comparison of ET measured with neutron moisture meters and weighing lysimeters. pp. 202-209. In: Proc. Irrigation and Drainage National Conference, IR Div/ASCE. USA-CO-Durango, 1990/07/11-13.

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Abstract

The neutron moisture meter (N.M.) method of determining crop water use is
frequently used in research and irrigated agriculture. This study was conducted to
compare crop evapotranspiration (ET) estimated by the N.M. method with ET measured
with a weighing lysimeter. Neutron meter data were obtained in a furrow-irrigated field
of alfalfa (Medicago sativa L) equipped with a weighing lysimeter and in alfalfa plots
irrigated with a line-source sprinkler system. Seasonal ET estimated from the N.M. data
for the furrow irrigation treatment was 15% less than lysimeter ET when only a 2-m soil
profile was considered, and was 10% less than lysimeter ET for a 3-m profile. The
seasonal ET estimated from N.M. data for the sprinkler treatment with a dry subsoil layer
was within 2.5% of lysimeter ET. The N.M. method lacked capability of measuring root
extraction of water from the relatively wet, lower soil layers which existed with furrow
irrigation.

Item Type:	Conference or Workshop Item (Paper)
NWISRL Publication Number:	0704
Subjects:	Water > Evapotranspiration Research methodology Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:57
Last Modified:	22 Dec 2016 16:04
Item ID:	1053
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/1053