Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
and soil loss over the future periods was estimated using the respective baseline values.
Plausible adaptation strategies were simulated in two categories: (i) residue
addition/mulching (organic and inorganic) and (ii) sub-surface drainage system (plastic pipes
and clay tile at 0.61 m deep) on cultivated HMWs, i.e., HMW3 to HMW6. The residue
considered to be locally available dry beans, field beans, soybeans, maize, broom grasses, and
stone mulch in the inter-cropped area.
Results
Measured soil erosion revealed that forests (HMW 1) had a mean (of 24 years) annual runoff
loss of 405.5 (±113) mm, while soil loss was 11.0 (±2.4) Mg ha -1 yr -1 . In the cultivated
HMWs (HMW4, 5 & 6), adoption of soil water conservation measures (SWCMs) reduced the
runoff by 13.0% – 17.1% and soil loss by 12.6%–15.1% over HMW 1. However, in shifting
cultivation (HMW7), runoff increased by 50.6%–87.6%, while soil loss was 50.3%–59.8%
higher over the forest. The average annual runoff calibrated and validated by the
WEPP model was comparable to the measured runoff and the differences were negligible (p
< 0.05). The normalized RMSEn was 0.81
during calibration and >0.75 during validation periods for all HMWs, indicating that model
performance could be assessed as "very good".
The projected annual SE (average) for all HMWs increased in all RCPs. The IFS based on
shifting cultivation (HMW2) was the most vulnerable, with the highest percentage increase in
SE (46–235%) compared to the baseline years under RCP 8.5. The cultivated IFSs (HMW3 to
HMW 6) had 47.8–57.0% less runoff and 39.2–74.6% less soil loss than HMW 2 under RCP
8.5. Of these, HMW6 followed by HMW4 and HMW5 were more effective in minimizing soil
loss (Table 1). The simulated the effects of mulching (both organic and inorganic) in all the
cultivated IFSs (HMW 3 to HMW 6) declined with an increase in the mulch application rate
from 5.0 to 20 t ha -1 . Among organic mulches used, broom grass mulching at an application
rate of 20 t ha -1 resulted in a maximum reduction in soil loss of 8.7, 9.3, and 11.9 t ha -1 yr -1 in
the years 2020s, 2050s, and 2080s, respectively, compared to non-mulching. However, with a
low residue application of 5 t ha -1 , dry bean residues were most effective in controlling soil
erosion. Under stone mulching, simulated soil loss is projected to decrease in the range of 7.7
to 13.3 t ha -1 yr -1 when applied @ 20 t ha -1 during 2080s. The adoption of underground
drainage systems has demonstrated that the 6-inch diameter plastic pipe installed at a distance
of 7 m provides a greater reduction in projected SE than a clay tile of the same diameter
installed at a distance of 24 meters.
Climate resilient agriculture for risk mitigation
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