Effect of humic acid application and foliar spraying of compost tea and vermiwash on nutrient absorption and chlorophyll content of safflower (Carthamus tinctorius L.)

Humic acid as an organic acid produced by humus and other natural resources can improve nutrients absorption and seed yield. In order to study the effect of granular humic acid and foliar application of compost tea and vermiwash on nutrient absorption, chlorophyll content and seed yield of safflower (Carthamus tinctorius L.), an experiment was conducted as a factorial experiment based on randomized complete block design with three replications in agricultural research farm at Vali-e-Asr University of Rafsanjan. Treatments included of soil application of humic acid (0, 500, 1000 and 1500 kg ha-1) and foliar spraying of vermiwash 1:10, vermiwash 1:20, compost tea and distilled water as control. Results indicated that humic acid application had significant effect on the zinc, nitrogen and phosphorus content of shoot, chlorophyll index and seed yield. On the other hand, compost tea foliar application significantly influenced zinc and copper content of shoot, chlorophyll content and seed yield of safflower. It seems humic acid application (1500 kg.ha-1) in soil along with compost tea foliar application was the best treatment for producing of seed yield and higher nutrition absorption, chlorophyll content in safflower.