*4.2.4 Bench terracing*

The impact of bench terracing on runoff, soil loss, and soil properties along with Sapota (*Achras zapota*) growth, fruit yield, biomass, and carbon stock in a degraded ravine land developed along the course of *Mahi* River in Western India were evaluated. The bench terracing in deep ravines with uniform slope of 15% resulted in significant decrease in runoff (34%) and soil erosion (25%), and enhanced tree growth, biomass and carbon stock. The cultivation of crops in between the tree plantation may induce significant soil loss (18% higher) due to tillage operations even though the runoff is not significantly affected. The findings suggested that bench terracing is the best soil and water conservation measure for restoring highly degraded ravines [3].

## *4.2.5 Trenching*

The impact of trenching in deep ravines was evaluated ravines developed along the Mahi River in Western India. The staggered contour trenches were designed based on maximum daily rainfall. The trenching density on the ravine slopes was kept to retain 30, 50 and 80% of runoff generated from the ravine catchment. A substantial reduction in runoff was observed for treatments with higher trench densities (50% and 80%) as compared to 30%. The sediment yield in different trench densities also followed the similar trend. The soil moisture was more or less similar in different trench densities just followed by the monsoon. However, soil moisture in the 80% trench density was highest and also remains for a longer period in the lower reaches of the ravine slopes. The survival of Neem (*Azadirachta indica*) saplings planted at a spacing of 6 m × 6 m was also recorded and was also found highest in 80% trench density. In another study, the trenching of size 2 m × 0.5 m × 0.5 m at 14% uniform slope with Sapota plantation resulted in decrease in runoff by 16% and soil loss by 15% along with enhanced tree growth, biomass and carbon stock in the deep ravine slopes [11].
