Organic carbon in humic fractions in soil influenced by organic, inorganic and bio nitrogen fertilizers under different incubation periods

الملخص EN

Humic substances can be subdivided into three major fractions Humin (Hu), Humic acid (HA) and Fulvic acid (FA).

Humic substances are a good source of energy for beneficial soil organisms, plus its key fractions of soil organic matter, a major aspect controlling the flexibility of plant nutrition irrespective of land use system through different processes and mechanisms.

The main objective of this study was to investigate changes in the content of humic, non-substances in soil treated with manure, inorganic and bio nitrogen fertilizers under different incubation periods.

soil samples were collected after 14, 30 and 60 days from incubation to determined HA, FA, and Hu.

In the first period, results showed that the application of mineral fertilizers increased the contents of humic acid compared with fulvic acid in the soil.

Thus, the application of rabbit manure resulted in the most significant increase in the content HA compared with control treatment, and vice versa with the FA.

The humic substances in this study is characterized by higher content of FA than HA after the third period of incubation 60 days, significant differences between some treatments in terms of humin content than observed for control treatment.

The overall trend was humin (36 to 47%) > HA (7 to 37%) > FA (10 to 34%).

More FA than HA were observed in the second and third period, with the exception of the first period was less.

After 60 days incubation period, the HA/FA ratio varied from 0.42 to 1.53 ppm for all treatments, except (FOB) treatment was 2.22 ppm.

More FA than HA indicates low humification rates.

The distribution of C among the different fractions changed during incubation periods, due to the rabbit manure and nitrogen fertilizer added to the soil.