Effects of Soil Application of Humic Acid and Foliar Applications on Yield, Yield Component and Oil Content of Safflower (Carthamus Tinctorius L.)

Safflower (Carthamustinctorius L.) is an important oil seed plant that grows throughout the semiarid regions in many parts of the world. Humic acid is the main humic substance and the important ingredient of soil organic matter (humus) which causes increase of yield and quality of crop. Aerial compost tea contains high populations
of live microorganism consisting of rhizobactria, trichoderma and pseudomonas species which increase the growth and yield of the plant. Vermiwash as the extract of vermicompost is a liquid organic fertilizer obtained from unit of vermiculture and vermicompost as drainage. It is used as a foliar spraying on the leaf. The aim of this research is evaluating the effect of humic acid and foliar application of compost tea and vermiwash on yield, yield component and oil content of safflower.
In order to study the effect of granular humic acid and foliar application of compost tea and vermiwash on yield, yield component and oil content of safflower (Carthamus tinctorius L.), an experiment was conducted as a factorial based on randomized complete block design with three replications in agricultural research farm at Vali-e-Asr University of Rafsanjan. Treatments were included soil application of humic acid (0 (control), 500, 1000 and 1500 kg.ha-1) and 4 level of foliar application of distilled water as control, vermiwash with dilution 1:10 and 1:20 and compost tea.
Results showed that the effect of different levels of humic acid on the plant height, head weight, seed number, thousand seed weight and oil percent were significant but the foliar application treatments and their interaction have no significant effect. . The increase of head weight in safflower by using of humic acid could be related to the higher seed number and thousand seed weight. Stem diameter, total head number, fertile head number, oil yield and seed yield significantly affected by humic acid and foliar application treatments; however their interaction had no significant effect on them. It seems that humic acid would increase photosynthesis and plant metabolism which cause higher saving carbohydrate and decrease source limitation which translocate more sap to seed and increase thousand weight of safflower seed.
The results of this research showed that the highest application of humic acid (1500 kg.ha-1) increased plant height, stem diameter, head weight, head number, fertile head number, seed number, thousand seed weight, oil percent, oil yield and seed yield in safflower. It is also resulted that the highest stem diameter, total head number, fertile head number, oil yield and seed yield were observed in foliar application of compost tea. It is concluded that in Rafsanjan climate and the same region climate, application of 1500 kg.ha-1 humic acid and compost tea as foliar application is the best treatment for increasing seed yield, yield component and oil percentage of safflower