IRRIGATION OF THE SUNFLOWER IN CONJUNCTION WITH THE PHENOLOGICAL STAGES IN RELATION TO THE AVAILABILITY OF WATER IN THE SOIL

Here we report the results of biennial trial (1987–1988) carried out in the Sele river plain (Battipaglia).

The trial was carried out with the aim to verify the response of sunflower crops, irrigated at different plant development stages, in relation to precocity of three hybrids: 'Romsun HS 90' (early), 'Gloriasol' (medium) and 'Stromboli' (late) and in relation to the available water in the soil at the moment of irrigation or at 100 % ETM reintegration.

Limited water irrigations in number of one irrigation, at the "beginning flower stage" (BF) with 686 m³/ha, or of two irrigations at "flower bud stage" (BF) and at "beginning flower stage" (BF) with 956 m³/ha or at "beginning flower stage" (BF) and at "middle seed growth stage" (MG) with 1 155 m³/ha, gave yields of 3.1, 3.3 and 3.5 t/ha respectively.

The yields obtained with three irrigations (volume 1 509 m³/ha), distributed in "FB", "BF" and "MG" stages (3.7 t/ha in achenes yield) were higher than the yield obtained with the smaller irrigations volumes (686 and 956 m³/ha).

With the full ETM reintegration (2 500 m³/ha) we obtained the highest yield (4.1 t/ha in achenes), but this irrigation trial required a heavy seasonal irrigation volume.

The unirrigated control recorded a yield of 2.4 t/ha in achenes and 1.0 t/ha in oil.

Referring to the oil yield the higher productions were obtained with the three irrigations with higher seasonal volumes (2 500 m³/ha = 1.9 t/ha and 1 509 m³/ha = 1.7 t/ha) and also with two irrigations (1 155 m³/ ha) in "BF" and "MG" stages (1.7 t/ha).

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