Nature-based solutions for enhancing CO2 sequestration and rehabilitating degraded lands through silvo-aromatic system and soil moisture conservation techniques

Abstract

Ravine land is one of the most degraded lands which results from extreme soil erosion. The soil fertility in these lands is low which affects plant survival, making the cultivation of arable crops impractical. However, with the use of soil moisture conservation (SMC) techniques, the productivity of these areas can be significantly enhanced. The present study aims to rehabilitate the ravine area by combining aromatic grass, tree planting, and SMC techniques. We hypothesized that silvo-aromatic system combined with SMC measures will lead to significant improvements in CO₂-sequestration, soil organic carbon (SOC), and soil quality. The study involves planting Malabar neem (Melia dubia) along with lemon grass (Cymbopogon flexuosus) using a modified planting technique and SMC measures in seven different treatments in a randomized complete block design (RCBD). The effect of each treatment on soil health, productivity, and carbon sequestration was measured for six years (2019-2024). Results of the study revealed that the silvo-aromatic system (MLP) significantly (P < 0.05) improved the total tree biomass and total CO₂-sequestration with a 255 % increase over sole Melia (SMD). MLP performed statistically similar (P < 0.05) with Melia under modified micro site + lemon grass (MLM) in increasing soil nitrogen (N) by 78.1 %, phosphorus (P) by 73.2 %, potassium (K) by 78.5 %, and soil organic carbon (SOC) by 79.3 %, compared to untreated fallow land. Under MLP, there was an observed increase soil microbial biomass carbon (93.8 mg kg^-1), soil binding factor (598), soil moisture (24.9 %), treated-soil quality index (151.1), and CO₂-sequestration rate (0.98 Mg ha^-1 yr^-1). Therefore, it is recommended that silvo-aromatic system may be an environmentally friendly way to achieve land degradation neutrality. It has greater potential for the restoration of ravine lands, enhancing land productivity, and lessening the effects of soil erosion, especially in Western India.

Keywords: Carbon stock; Interception; Soil binding factor; Soil quality index; fine roots.