Humic substances promote the conversion of nutrients into forms available to plants. It also stimulates seed germination and viability, and its main effect usually being more prominent in the roots. This study was conducted in a randomized complete block design with three replications in Gobustan, Azerbaijan, in 2021 growing season, to determine the effects of different doses (0, 250, 500 and 1000 ppm) of humic substances such as humic acid (HA), fulvic acid (FA) and humic fulvic acid (HFA) on fresh yield and nutrient contents (N, P and K) of Eggplant Santana (Solanum melongena var. esculentum Santana) plants in a field experiment. According to the results of this study, humic substance treatments increased the fresh yields and leaf nutrient contents of Eggplant Santana, and this increase was found to be significant. The highest value for highest fresh yields and leaf NPK contents of Eggplant Santana plants were obtained from 1000 ppm HFA dose. These results suggest that 1000 ppm HA and FA combination to the standard humic substances application will be sufficient to obtain adequate fresh yield and nutrient contents in Eggplant Santana leafs.

The aim of this study was to investigate impact of bio-humus on Cardinal grape yield (Vitis vinifera L.) and nutrient contents of dark brown soil using drip irrigation systems under the open field conditions in the vineyard region of Azerbaijan. A field experiment was conducted in a Cardinal Vineyard farm located in Shamakhi district, Azerbaijan between May and October 2021. An experiment with one dose of bio-humus treatment (5 t.ha-1) and three replications, with a plot size of 1 ha treatment was used. There were performed drip irrigation, starting from May 15 up to September 15, every 15 days. The soil sampling and measurements carried out after harvest the application of bio-humus in soil and the soil samples were collected from depth of 20 cm. The results showed that addition of bio-humus increased fresh berryweight yield, contents of organic matter, total N, available P, and available micronurtient (Fe, Cu, Zn and Mn) in soil compared with control plots. The soils treated with bio-humus had significantly more EC in comparison to unamended plots. The addition of bio-humus in soil resulted in increase of soil pH.