RESPONSE OF BROCCOLI TO FIVE SOIL WATER REGIMES
Plants of broccoli, Brassica oleracea var. italica, were grown in weighing lysimeters and exposed to five soil water regimes. These regimes restored soil water to field capacity at 88% of available water for the wet treatment, 60% for the medium and 32% for the dry. In the wet–dry and dry–wet regimes, water depletion levels were changed at time of head formation. Soil water stress imposed prior to heading reduced plant size, but yield of marketable heads was not significantly reduced from that of plants grown in the wet regime when an adequate water supply was maintained after heading. Yield of marketable heads was least in the dry and wet–dry regimes and intermediate in the medium regime. Plants in the dry–wet regime did not consume as much water as those in the wet regime during the period from heading to harvest. In maritime areas which do not normally experience excessively high temperatures, withholding irrigation until heads begin to form can be recommended, provided the soil type is capable of retaining moisture and is at field capacity at planting.