Effects of biochar application on yield and yield components of black seed (Nigella sativa L.) under low irrigation conditions

A field experiment was conducted focusing on the effects of biochar on quantity characteristics of Black Seed (Nigella sativa L.) under water deficit conditions. The experimental design was split plot factorial in a randomized complete block design with three replications. Three levels of irrigation (I1: 100%, I2: 70% and I3: 40% of water irrigation requirement) were assigned as main plots and the combination of three levels of biochar (B1: 0, B2: 10 and B3:20 t.ha-1) and two levels of chemical fertilizers (F1: without and F2: with chemical fertilizer) were allocated as sub plots. Results were shown that seed number per plant and seed weight per plant significantly increased by 10 t.ha-1 biochar application compared with 20 t.ha-1. Chemical fertilizer significantly affected the yield components of black seed except 1000-seed weight. The interaction between biochar, chemical fertilizer and water requirements significantly affected the seed yield and biological yield. The result revealed that the application of 10 t.ha-1 biochar plus 70% water irrigation requirement and using chemical fertilizer (I2B2F2) produced the highest seed yield and biological yield (1365 and 5776 kg.ha-1, respectively). Application of biochar combined with chemical fertilizers could improve soil nutrient and water availability conditions and increased the yield of black seed.