Organic Materials and Their Chemically Extracted Humic and Fulvic Acids as Potential Soil Amendments for Faba Bean Cultivation in Soils with Varying CaCO3 Contents

Abstract

Organic amendments are important sources of nutrients that release upon organic matter degradation, yet the stability of these organics in arid and semi-arid regions is relatively low. In contrast, humic substances (HS) are resistant to biodegradation and can keep nutrients in the soil available for the plant over a long time. Combinations between humic substances (HS) and mineral-N fertilizers are assumed to retain higher available nutrients in soils than those recorded for the sole application of either mineral or organic applications. We anticipate, however, that humic substances might not be as efficient as the organics from which they were extracted in increasing NP uptake by plants. To test these assumptions, faba bean was planted in a pot experiment under greenhouse conditions following a complete randomized design while considering three factors: two soils (calcareous and non-calcareous, Factor A), two organics (biogas and compost, Factor B) and combinations of the organics and their extracts (HA or FA) together with complementary doses of mineral-N ((NH4)2SO4) to attain a total rate of 50 kg N ha−1 (the recommended dose for faba bean plants) (Factor C). Results indicated that nitrogenase activity increased significantly due to the application of the used organics. In this respect, compost manure caused higher nitrogenase activity than biogas manure did. Humic substances raised NP-availability and the uptake by plants significantly; however, the values of increase were lower than those that occurred due to the compost or biogas manure. Moreover, the sole application of the used organics recorded the highest increases in plant biomass. Significant correlations were also detected between NP-availability, uptake and plant biomass. This means that HS could probably retain nutrients in available forms for long time periods, yet nutrients released continuously but slowly upon decomposition of organics seemed more important for plant nutrition.

Introductory Chapter: Climate Change and Climate-Smart Greenhouses

“…Biodiversity enhancement can also aid climate mitigation [38]. Organic extracts, such as humic and fulvic acids or compost tea, promote plant growth, sequestering more CO 2 in plant tissues [39][40][41]. In the health sector, adaptation focuses on enhancing public health infrastructure to manage heatwaves and disease outbreaks, incorporating early warning systems, and improving air and water quality [42].…”

Wheat Productivity as Influenced by Integrated Mineral, Organic and Biofertilization

“…A point to note is that the application of humic and fulvic acids as partial substitutes for mineral fertilizers may effectively increase crop productivity (Man-hong et al, 2020;El-Shwarby et al 2022); yet these organics decreased both straw and grains yields versus application of 100% PK in the results obtained herein. Probably, these organic components bound nutrients forming complexes that plants cannot breakdown and utilize (Farid et al 2021a).…”

“…63, No. 3 (2023) 288 nutrients are set free in available forms (Abdelhafez et al, 2018;Cai et al 2019) to improve the nutritional status of grown plants (Abbas et al 2020;Farid et al, 2021a). Even the relatively resistant biodegradable organic components, named humic substances (El-Shwarby et al 2022) can be used sucessfully to increase crop production.…”

Humic Acids Enhance Potentially Toxic Elements (PTEs) Phytoextraction from a Contaminated Soil by Basil Plants

“…Humic acids were found to be among the physiochemical approaches that can control available contents of PTEs in soil (Rong et al, 2020). It is one of the three main components of organic residues humic acids (HAs), fulvic acids (FA), and humin (Farid et al, 2018 andElshaboury and Sakara, 2021;Elramady et al, 2022). This fraction is not soluble in water under acidic conditions, but become soluble and extractable at higher pH values (Kleber and Lehmann, 2019).…”

“…Elemental analysis for carbon, hydrogen, nitrogen and sulphur contents of the purified humic acids was performed by gas chromatography Hewlett-Packard in the Micro Analytical Center, Faculty of Science, subtracting total amount of carbon%, hydrogen %, nitrogen % and sulphur % from 100 (Farid et al, 2018). The obtained results are presented in Table 3.…”