Soil Organic Fractions in Cultivated and Uncultivated Soils of Costal Area in Bangladesh

Ipsita Sarkar,Md Zulfikar Khan,Md Hanif

doi:10.4236/jacen.2019.83011

Ipsita Sarkar, Md Zulfikar Khan + Show 1 more

Open Access

https://doi.org/10.4236/jacen.2019.83011

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Abstract

Assessment of soil organic matter fractions can be instrumental in understanding the causes of limited nitrogen supply, and thus soil fertility restoration. A study was conducted in cultivated and uncultivated saline soil, in order to assay soil organic carbon (SOC), its particle-size fractions and their influence on cultivation and soil fertility at Sundarbans costal area in Bangladesh. Soil samples were taken from the 0 - 15 and 15 - 30 cm depths from four cultivated fields and from four nearby sites in a native mangrove forest as references. Soil samples were physically fractionated into sand (2000-50 μm), silt (50-2 μm) and clay ( silt > sand. The SOC pool and N in the clay-sized fraction were correlated to soil fertility indicators. More N was stored in the silt + clay size fractions, a generally more stable pool, than in the more labile sand-sized pool. The SOC pool in sand size fractions was far below in cultivated soils than in a reference uncultivated soil. Thus, the sand-sized pool emerged as the most likely cause of limited N supply in cultivated soils.

Highlights

Soil salinity is a hazard in coastal area just as in Sundarbans in Bangladesh
There was a general increase in the importance of the silt-sized soil organic carbon (SOC) pool
In this study indicate that the soil organic carbon and nitrogen were significantly decreased after cultivation within the cultivated fields and cultivation decreases the organic matter in soils

Summary

Introduction

Soil salinity is a hazard in coastal area just as in Sundarbans in Bangladesh. The cultivable lands in this region are affected with varying degrees of soil salinity and restrict plant growth. Sodium (Na+) is the predominant soluble cation in most saline soils of the coastal area [1]. Salt-affected soils exhibit poor soil structure resulting from soil physical processes such as slaking, swelling, and dispersion of clay [3]. Soils of this area are poor in fertility with low (1.0% - 1.5%) organic matter content. Low SOC concentrations and reduced nutrient retention capacity further increase leaching of applied nutrients and lead to land abandonment by farmers [5]

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