Storage and Flux of Nutrients in Disturbed and Undisturbed Tropical Moist Forest of Eastern Nepal

Tej Narayan Mandal,Tilak Prasad Gautam

doi:10.1155/2018/8516321

Tej Narayan Mandal, Tilak Prasad Gautam

Open Access

https://doi.org/10.1155/2018/8516321

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Abstract

The disturbance activities in tropical forests shrink the nutrient cycling between the vegetation and soil. To understand the nutrient cycling in undisturbed and disturbed stands of mixed deciduous tropical forest of eastern Nepal, plant biomass was estimated within seventy randomly established sampling plots. The biomass values were multiplied with nutrient concentration of respective parts to estimate the nutrient stocks. The nutrient concentrations varied widely amongst components. In trees, concentrations of all nutrients were highest in leaves followed in decreasing order by fine roots (<5 mm) and twigs and then by branches, bole, and coarse roots. The contribution of different components to total nutrient stocks was in the following order: tree > stand fine root > shrub > herb, in both stands. The relative contribution of different components of trees to total nutrient stocks was in the following order: bole > coarse root > branch > leaf > twig > fine roots. In trees, leaves and fine roots had greater gross uptake of nutrients than other components. The concentrations of different nutrients in the plants are in the following order: nitrogen > potassium > phosphorus. Total nutrient return to the soil through the litterfall is almost 1.5 times greater than that from fine roots in both forests. In conclusion, various types of forest disturbances had adverse effect on the nutrient stocks and nutrient dynamics.

Highlights

Nutrient dynamics is an important phenomenon for the understanding of ecosystem functioning and ecological status
Concentrations of all nutrients were highest in leaves followed in decreasing order by fine roots (
The contribution of different components to total nutrient stocks was in the following order: tree > stand fine root > shrub > herb, in both forests

Summary

Introduction

Nutrient dynamics is an important phenomenon for the understanding of ecosystem functioning and ecological status. The nutrient cycling in forest ecosystem comprises cyclic circulation of nutrients between forest soils and plants. The nutrient status of a forest ecosystem depends on the balance between nutrient inputs (deposition, fixation, and weathering) and outputs (leaching and volatilization) [1]. Nutrient uptake, their retention, and release are the three components of nutrient dynamics in forest ecosystem. More uptake of nutrients and less return to the soil leads to degradation of land and lowering the productivity. Litter and fine roots are regarded as the forest nutrient pool linking inputs, output, and turnover of nutrients. Nutrients accumulated in nonphotosynthetic parts (stem and roots) form the retention component while those accumulated in leaves return to the ecosystem through litter fall

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Conclusion