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White Clover Seed Production: I. Crop Water Requirements and Irrigation Timing
Author(s) -
Oliva R. N.,
Steiner J. J.,
Young W. C.
Publication year - 1994
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1994.0011183x003400030029x
Subject(s) - trifolium repens , agronomy , loam , irrigation , canopy , biology , soil water , crop , stolon , water use , environmental science , botany , ecology
White clover ( Trifolium repens L.) seed production may be increased by soil‐water deficits during flowering. This study was conducted on a Woodburn silt loam (fine‐silty, mixed, mesic Aquultic Argixeroll) in 1990 and 1991 to determine white clover seed crop water requirements and supplemental irrigation timing. A crop water stress index (CWSI) was calculated and the fraction of available soil‐water used was used to determine white clover seed crop water requirements. Under minimal‐stress conditions, depleted soil‐water was replenished twice weekly to field capacity with the water amount used since the last application. Four treatments had a single water replacement to 100% field capacity when 25, 46, 68, and 84% of the available water was used in 1990 and 30, 57, 64, and 79% in 1991. A nonirrigated control was also maintained. We identified two distinct CWSI non stressed baselines for canopy‐air temperature differences versus vapor pressure deficit that were related to crop aging but not to canopy floral display. Maximumse ed yield water‐use efficiency was obtained in 1990 when water application was delayed until 68% of the available soil‐water was depleted and CWSI was 0.46. In contrast to 1990, in 1991 none of the single water application treatments affected seed yield because flower production was reduced by dense stolon production. The CWSvI alues across all treatments in both years weren egatively related to leaf water potentials ( r = −0.86).