Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
Results
Total organic carbon (TOC)
The TOC concentration in soil layers varied depth-wise (Table 1). During 2020, the highest
concentration of TOC was observed in 0–15 cm depth and exponentially decreased with
increase in depth after each crop harvest. Depth 0–15 cm of 100% NPK+ FYM plots
witnessed 146.36 % increased concentration of TOC at the harvest. The application of FYM
during the years confined to build soil organic carbon on surface layers only. Cultivation only
with balanced fertilization (NPK) and C supplementation (NPK+FYM) maintained or
increased the TOC content while no fertilization treatments decreased it (Majumderet al.,
2007). Despite, fertilizer treatment 100% NPK and FYM balanced the C: N ratio and energy
for soil biota which helped in augmenting the TOC of the soil. Manjaiah and Singh (2001)
also reported an annual estimated organic carbon input to the tunes of 8190 and 2780 kg ha −1
in 100% NPK + FYM and 100% NPK treatments, respectively.
Permanganaseoxidisable carbon (POXC)
The POXC concentration in soil layers varied depth-wise. During 2020, the highest
concentration of POXC was observed in 0–15 cm depth and exponentially decreased with
increase in depth after each crop harvest. Depth 0–15 cm of 100% NPK+ FYM plots
witnessed 23.21 %, increased concentration of POXC at the harvest. The application of FYM
during the years confined to build soil organic carbon on surface layers only.
Significantly higher libale carbon fraction of Very liable carbon, liable carbon and less liable
carbon were observed in 100% NPK+ FYM (Table 2) in top layer of 0-15 cm which is of
39.23% , 177.78% and 40.78% higher than control, respectively. Within the labile carbon
fractions higher value of very liable carbon fraction was found as compared to other two.
The KMnO4 extractable C, which is considered as a labile C fraction of soil. The surface soil
acquired more KMnO4 extractable C than sub-surface soil after harvests. Treatment 100%
NPK + FYM showed significantly higher KMnO 4 extractable C over allother treatments at all
depths after the harvest of both crops. Thebalanced applications of N, P and K (100% NPK)
showed higher KMnO 4-C than that of control and unbalanced treatment. This indicatedthat
the added FYM contributed to the KMnO 4 oxidized labile C fraction in soil which is
composed ofamino acids, simple carbohydrates, a portion of microbial biomass and other
simple organic compounds (Zouet al., 2005). Also, the application of nitrogen ascribed the
priming effect of applied N on freshorganic matter in soil which stimulated microbial action
in decomposition of organic matter.
Sustainable soil management for resilient rainfed agro-ecosystem: conservation agriculture, organic farming,
INM, soil-microorganisms-plant interactions
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