الملخص الإنجليزي
Controlling the greenhouse gas emissions from agricultural practices has become a popular
topic for environmental researchers to mitigate the effects of climate change. Also, improves
the productivity of the agricultural sector. Thus, the application of soil amendments could
help achieve this goal. This study aimed to evaluate the effect of the co-application of
elemental sulfur with biochar and compost on plant growth, emission of greenhouse gases
(GHG), and soil health and fertility. The experiment was conducted using three different soil
amendments: compost (C), biochar (B), elemental sulfur (S), and their combinations, with a
total of eight different treatments and four replications of each. The emissions of GHG (CO2,
CH4, and N2O) were measured for 90 days using a closed chamber connected to a gas
analyzer device. The chemical properties of soil samples included soil pH, EC, organic matter
content, available phosphorus, total elemental composition, and percentage of calcium
carbonate. For microbiological analyses, different growth media to culture bacteria,
actinomycetes, and fungi were used. In addition, the soil samples were assayed for respiration
rate, microbial diversity by 16S rRNA V4 gene sequencing, and soil enzyme activity,
including urease, dehydrogenase, phosphatase, and fluorescein diacetate hydrolase activity.
The addition of S alone or in combination with compost has been shown to reduce soil pH;
however, the combination of sulfur with biochar buffer reduces soil pH. The addition of
biochar increased the OM in the soil, only about 40% remained after 2 months. However, the
combined application of biochar, compost, and elemental sulfur (S+C+B) resulted in the
highest OM accumulation in the soil (about 46%). In addition, this combination enhances
microbial growth (bacteria, actinomyces, and fungi) and enzyme activities, which ultimately
improve soil health and fertility. The biochar treatments exhibited higher total operational
taxonomic units (OTUs), as well as increased Shannon and Evenness diversity indices,
indicating greater ecological resistance to environmental changes. Based on the niche map
clustering some species show a high abundance in certain treatments. Nitrosovibrio tenuis
has dominated in elemental sulfur treatment which is Ammonia-oxidizing bacteria involved
in the nitrification process, also,this treatment dominated by Thiobacillus denitrificans
(denitrification microbes). Cellvibrio ostraviensis was found to be in high abundance in
compost which carries out the reduction of nitrate to nitrite (contribute to N2O). Results also
showed that the addition of elemental sulfur alone enhanced methanotrophic microbes and
significantly reduced the average emissions of CO2 by 48%, N2O by 94%, and CH4 by 76%,
whereas biochar alone significantly reduced the average emission of two gases CO2 and N2O
by 46% and 70%, respectively, CH4 the reduction was not significant. These findings
underscore the importance of integrated soil amendments in enhancing soil health, and
microbial diversity, and mitigating GHG emissions from agricultural practices, thus
contributing to global efforts in climate change mitigation and sustainable agriculture.
