Safflower (Carthamus tinctorius) is only known in its cultivated form with centres of origin probably in the Near East. The estimated world production is about 0. 6 million tons of seed per year from about 0.85 million ha.(FAOSTAT, 2001). The flowers from the spiny cultivars are grown for oil, while some spineless cultivars are used for dye production.
Safflower is not suited to lowland, humid tropics. Large scale commercial cropping is practised in USA and USSR between 30° and 45°N and in Australia between 15° and 35°S. Emerging plants need cool temperatures for root growth and rosette development (mean daily temperature 15 to 20°C) and higher temperatures during stem growth, flowering and yield formation periods (20 to 30°C). There is no germination below 2°C. At 5°C germination takes 16 days and at 16°C, 4 days. The seedling is frost-resistant up to -7°C but after this stage frost below -2°C kills the plant. The crop seems to be sensitive to daylength but the effect is difficult to quantify. The length of the growing period for an autumn-planted crop varies from 200 to 230 days; when planted in spring, 120 to 160 days.
Safflower requires a fertile, fairly deep and well-drained soil. For irrigated production a medium-textured soil is preferable. Shallow soils seldom produce high yields. On suitable soils roots go down to 3.5m; dense subsoils retard root growth. The crop is well adapted to the presence of a water table at a depth of up to 1 m. Under irrigation, the fertilizer requirements are 60 to 110 kg/ha N, 15 to 30 kg/ha P and 25 to 40 kg/ha K. Though there is a rather wide tolerance to H, high yields are obtained on soils with a neutral reaction; when pH is lower than liming may be advisable.
The crop is moderately tolerant to salinity, ranking just below cotton. Yield decrease due to soil salinity is 0% at ECe 5.3, 10% at 6.2, 25% at 7.6, 50% at 9.9 and 100°/ at ECe 14.5 mmhos/cm. During germination the seedlings are about half as tolerant, which is relatively high compared to other crops.
Row spacing varies from 0.5 to 0.8 m, with 15 to 35 plants per metre of row. Seed rate for broadcast sowing of the irrigated crop is 40 to 50 kg/ha; for row crops, seed rate is 20 to 25 kg/ha.
The graph below depicts the crop stages of safflower, and the table summarises the main crop coefficients used for water management.
Stages of Development
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Stage length, days
Depletion Coefficient, p
Root Depth, m
Crop Coefficient, Kc