California Crop Fertilization Guidelines

UC Davis
A collaboration between CDFA, FREP and UC Davis

Safflower Nitrogen Uptake and Partitioning

The Fertilization guidelines can also be found on the UC Davis Nutrient Management website .

Seasonal N Uptake

Season N Uptake Curve Graph

Nitrogen uptake in irrigated safflower in Yolo County. Seeding rate was 25 lbs/acre. The field was fertilized with 175 lbs N/acre and the average yield was about 2500 lbs/acre. Safflower takes up N slowly during the rosette stage, until about a month after emergence. Growth and uptake is rapid during stem elongation and branching. After flowering, during the grain filling period, most of the N is translocated from the vegetative parts to the grain and N is no longer taken up [1,6].

Nitrogen Partitioning

Nitrogen partitioning pie chart

Nitrogen distribution in safflower plants grown in Yolo County from 1994-1995. "Seeds" indicates the harvested shells and kernels, or achenes. On average, 50% of total safflower N was allocated to the harvested seeds. Nitrogen partitioning can vary with year, location and variety [1].

Nitrogen Removed at Harvest

Nitrogen removed with harvested safflower seeds. "Seeds" refers to the achenes (kernel+hull). The overall average is weighted for the number of observations in each trial. More information can be found here [3].

Location Years Removal (lbs N/ton at 8% moisture) Source
    Mean Range  
California 1994-95 48.8 34.8-58.6 [1]
Montana 1977-78 63.1 48.9-71.2 [5]
Montana 2000-03 59.5 57-63.7 [8]
Various 1967 54.9 45.3-66.2 [4]
Greece 1998-99 77.2 47.2-109.3 [7]
Greece 2004-05 40.6 33.8-45.7 [2]
Iran 2013-14 49.0 36.6-59.4 [9]
Various   49.2   [10]
Weighted Average   56.8 33.8 - 109.3  



  1. Cavero, J., Plant, R.E., Shennan, C., Friedman, D.B., Williams, J.R., Kiniry, J.R., Benson, V.W., 1999. Modeling nitrogen cycling in tomato-safflower and tomato-wheat rotations. Agricultural Systems 60, 123-135. Complemented with unpublished data.
  2. Dordas, C.A., Sioulas, C., 2009. Dry matter and nitrogen accumulation, partitioning, and retranslocation in safflower (Carthamus tinctorius L.) as affected by nitrogen fertilization. Field Crops Research 110, 35-43.
  3. Geisseler, D., 2016. Nitrogen concentrations in harvested plant parts -A literature overview. Report to the Kings River Watershed Coalition.
  4. Guggolz, J., Rubis, D.D., Herring, V.V., Palter, R., Kohler, G.O., 1968. Composition of several types of safflower seed. Journal of the American Oil Chemists Society 45, 689-693.
  5. Haby, V.A., Black, A.L., Bergman, J.W., Larson, R.A., 1982. Nitrogen fertilizer requirements of irrigated safflower in the northern Great Plains. Agronomy Journal 74, 331-335.
  6. Kaffka, S.R., Kearney, T.E., 1998. Safflower production in California. University of California Agriculture and Natural Resources Publication 21565.
  7. Koutroubas, S.D., Papakosta, D.K., Doitsinis, A., 2004. Cultivar and seasonal effects on the contribution of preanthesis assimilates to safflower yield. Field Crops Research 90, 263-274.
  8. Lenssen, A.W., Waddell, J.T., Johnson, G.D., Carlson, G.R., 2007. Diversified cropping systems in semiarid Montana: Nitrogen use during drought. Soil & Tillage Research 94, 362-375.
  9. Shahrokhnia, M.H., Sepaskhah, A.R., 2016. Effects of irrigation strategies, planting methods and nitrogen fertilization on yield, water and nitrogen efficiencies of safflower. Agricultural Water Management 172, 18-30.
  10. United States Department of Agriculture Natural Resources Conservation Service. Crop Nutrient Tool.