Improving the growth of black cumin (Nigella sativa L.) by humic acid and Trichodermia harzianum as biofertilizer

Abstract

Anwar Hussein Nassif, Rabab Majead Abd* and Najm Abdullah Jumaa Al-Zubaidi

A field experiment was carried out in one of the agricultural fields which belongs to the Khalis district in Diyala Governorate, Iraq, located at a distance of 16 km northeast of Baqubah, during the fall season of the year 2021-2022 in a soil with a clay texture. An experiment was carried out with the aim of studying the effect of organic fertilization with four levels of humic acid, namely 0, 2 g.M-2 and 4,6 g.M-2 and bio-fertilization with the Trichodermia harzianum fungus, which was added at a rate of 0.3 gm, affected some vegetative traits of Nigella Sativa L. The results showed that the treatment of adding humic acid at the level of 6 gm?² was significantly superior in terms of plant height, number of branches and dry vegetative weight, which amounted to 53.51. cm and 16.01 branches. plant-1 and 31.89 gr. plant-1, respectively, and the treatment of adding humic acid at the level of 4 g.m?² was significantly superior, with the highest mean of the index of chlorophyll in the leaves reaching 32.02 SPAD, compared to the control treatment, which recorded the lowest averages for the mentioned traits, respectively. Plant height, number of branches, dry vegetative weight and chlorophyll index, which were 48.30 cm and 16.71 branches. plant -1 and 43.37 g. plant-1 and 34.31 SPAD, respectively, compared to the control treatment, which amounted to 29.61 cm and 6.58 branches. plant-1, 27.25 gm?¹, and 27.50 SPAD, respectively