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Shifting cultivation has resulted in large-scale deforestation and forest degradation in the tropics; however the abandoned fallows are known to have high potential for carbon capture. The paper is an attempt to determine the forest recovery patterns following shifting cultivation by evaluating the tree species composition, diversity and abundance with respect to topographical factors in Manipur, India. We also used ordination analysis to understand the change in species composition with regard to environmental variables. The living woody biomass carbon of each fallow was quantified, and the factors affecting the recovery of carbon stock along an increasing fallow gradient was assessed. Our results showed that the species richness and basal area recovered relatively with time since abandonment, and the north-facing lower elevation fallow sites displayed higher species richness and stem density than those in higher elevations. Environmental variables had no impact on the regeneration of Elaeocarpus floribundus Blume and Castanopsis hystrix Hook. f. & Thomson ex A. DC. which suggests that they may be capable of effective restoration of degraded forest areas. As these species appear naturally in the forests, it would facilitate quicker rehabilitation and reinstate the soil nutrients making the soil reusable in a short term. We also found that fallow age plays a vital role in recovering above-ground biomass carbon from living woody species followed by the aspect of the site. The total living woody biomass carbon ranged from 0.98 Mg ha-1 in 5 years fallow to 142.58 Mg ha-1 in 20 years fallow. The above-ground biomass carbon recovery of the oldest fallow was 39% to 40% of the reference undisturbed forest and the estimated time for the shifting cultivation fallows to reach that of the undisturbed forest level was approximately 39 years to 41 years., Competing Interests: The authors have declared that no competing interests exist.

The increasing utilization of nanoparticles (NPs) in agricultural practices has led to a surge in demand for nano-based products. Herein, we investigate the dose-dependent impacts of nickel hydroxide (Ni(OH)2)/nickel (Ni) NPs, synthesized using Asparagus racemosus Linn. leaf extract, on the seed germination and growth of Vigna radiata (Linn.) Wilczek. In all seed samples, 100% germination was observed in Treatment 1 (2.74 mg mL−1) and Treatment 2 (5.48 mg mL−1) of Ni/Ni(OH)2 NPs. However, in Treatment 3 (8.22 mg mL−1) and Treatment 4 (10.96 mg mL−1), the germination percentage was lower, reaching 80%. Further, Treatment 5 (13.70 mg mL−1) of Ni/Ni(OH)2 NPs showed a reduced germination rate of 60%, indicating a prolonged germination process at higher concentrations. Remarkably, the length of seedlings showed a significant increase in all experimental treatments compared to the control group, which received 5 mL of distilled water. Among the investigated parameters, Treatment 2 demonstrated the most promising outcomes, exhibiting the highest chlorophyll stability index (23.73%) and membrane stability index (67.89%) values, as well as the lowest root ion leakage (24.75%). These findings indicate that Ni/Ni(OH)2 has the capacity to enhance seed germination and foster seedling growth. [ABSTRACT FROM AUTHOR]

Soil organic carbon plays an important role in the stability and fertility of soil and is influenced by different management practice. We quantified active and passive carbon pools from total soil organic carbon (TOC) in seven different land use systems of northeast India. TOC was highest (2.75%) in natural forest and lowest in grassland (1.31%) and it decreased with increasing depth in different pools of lability. Very Labile Carbon (VLC) fraction ranged from 36.11 to 42.74% of TOC across different land use system. Active carbon (AC) pool was highest in Wet Rice Cultivation (61.64%) and lowest (58.71%) in natural forest. Higher AC pools (VLC and less labile) in most land use systems barring natural forests suggest that the land use systems in the region are vulnerable to land use change and must adopt suitable management practice to harness carbon sequestration. [ABSTRACT FROM AUTHOR]