Comparison of Three Different Fertigation Strategies for Drip Irrigated Table Grapes - Part I. Soil Water Status, Root System Characteristics and Plant Water Status

  • P.A. Myburgh ARC Infruitec-Nietvoorbij1, Private Bag X5026, 7599, Stellenbosch, South Africa
  • C.L. Howell ARC Infruitec-Nietvoorbij1, Private Bag X5026, 7599, Stellenbosch, South Africa

Abstract

Three fertigation strategies were compared in a drip irrigated Dan-ben-Hannah/Ramsey vineyard near
Paarl in the Berg River Valley region of South Africa during the 2002/03 and 2003/04 seasons. Fertilisers
were applied either (i) three times per season, (ii) once a week from bud break to flowering, from fruit set
to véraison and for six weeks after harvest or (iii) in five to seven pulses per day. For each of the fertigation
strategies, grapevines bore normal or high crop loads, viz. 26 or 36 bunches per grapevine respectively.
Daily irrigation pulses of 20 to 40 minutes each maintained soil water matric potential above -0.01 MPa in
the wetted bulbs. Daily pulses accumulated to a seasonal total of ca. 490 mm irrigation compared to ca. 260
mm for weekly irrigation. Root structures of grapevines irrigated by means of daily pulses had adapted by
forming extremely dense root systems in the small wetted bulbs compared to the less frequently irrigated
grapevines. Monitoring diurnal grapevine water status revealed that the different fertigation strategies
did not affect water constraints up to véraison. During berry ripening, daily pulse irrigated grapevines
experienced less water constraints in the morning, late afternoon and during the night than less frequently
irrigated ones. However, the grapevines did not experience any detrimental water constraints throughout
the season, irrespective of fertigation and irrigation frequencies or crop load. It was evident that grapevine
water status not only depends on the size of the root structure, but also on the soil environment in which
the roots function.

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Published
2016-11-02
Section
Articles