Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
conventional Tillage – CT) and fallow fields which is not tilled and grass cover is maintained
throughout the year. three cropping systems (Pearl millet- chickpea – PM-C, Pearl Millet-
Chickpea- Fodder Pearl Millet – PM-C-FPM and Pearl Millet-Chickpea- Mung bean- PM-C-
M) in split plot design. After eight years of completion of cropping cycle, fresh and moist soil
samples are taken from 0-5, 5-15 and 15-30 cm of soil depth from each treatment and
analysed for different labile pools of SOC including cold water extractable organic carbon
(CWEOC); hot-water extractable organic carbon (HWEOC); Active carbon (AC) and total
SOC. CWEOC is quantitatively very close to dissolved organic carbon whereas the HWEOC
consists of more stable components that form the close reserve of nutrients and energy for
plants and microorganisms. Similarly, AC determined through 0.002 M potassium
permanganate is an active SOC pool and is well suited to track management practices that
promote soil C sequestration, making it a particularly useful indicator for soil quality
research. (Weil et al., 2003). The Total soil organic carbon was analysed through CHNS
analyzer. Data were statistically analyzed by one-way analysis of variance (ANOVA) using
doebioresearch package in R software (R Core Team (2022).
Results
CWEOC was the highest in the surface than in the sub-soil layers under every tillage and
cropping system treatments. CWEOC was similar for ZT+R, fallow and CT tillage practices
and these were higher compared to ZT-R treatment at 0-5 cm depth whereas at 5-15 cm depth
only ZT+R is significantly higher than other treatments. All the treatments remain nonsignificant
at 15-30 cm soil depth. There was no significant difference between cropping
systems throughout the soil depths. The interaction between tillage and cropping systems
were significant at 0-5 and 5-15 cm of soil depth. The highest CWEOC were observed in
ZT+R: PM-C-M (0.098 g kg -1 ) and ZT+R:PM-C-FPM (0.105 g kg -1 ) respectively at 0-5 cm
depth. Similarly, ZT+R: PM-C-M (0.10 g kg -1 ) and ZT+R:PM-C-FPM (0.10 g kg -1 )
treatments observed highest CWEOC at 5-15 cm soil depth and at 15-30 cm of soil depth
CWEOC ranges between 0.098 to 0.067 g kg -1 . The concentration of HWEOC was almost 2.8
times higher as compared to CWEOC at 0-5 cm depth. HWEOC also higher at surface (0-5
cm) than subsurface soil depths (5-15 and 15-30 cm). HWEOC content was highest in ZT+R
and fallow treatments as compared to ZT-R and CT treatments at 0-5 cm soil depths.
HWEOC was 3.28 times higher as compared to CWEOC at 5-15 cm soil depth. HWEOC was
highest in fallow (0.164 g kg -1 ) and CT (0.174 g kg -1 ) treatments as compared to ZT-R
treatments (0.121 g kg -1 ) whereas at 15-30 cm, treatments follow the trend: fallow> ZT+R =
CT> ZT-R. AC follow similar trend of HWEOC and CWEOC. AC was highest in ZT+R and
ZT-R treatments as compared to CT and fallow treatments at 0-5 cm soil depth but there was
no significant difference among tillage practices at 5-15and 15-30 cm of soil depth. The
highest AC content was observed in PM-C-M (0.509 g kg -1 ) and PM-C-FPM (0.475 g kg -1 ) at
0-5 cm soil depth. The interaction of tillage and cropping systems were significant at 0-5 and
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