Introduction
Western Ghats, one of the world’s ten “hottest biodiversity hotspots”,
was well covered with dense forest in the earlier days. Agro-ecosystems
in the Western Ghats have depended on the forests for raw materials for
food, fuel, fodder, fruits, timber, leaves, litter and various other
products. Despite this, due to the expansion in area for agriculture,
development of plantations and for other developmental activities,
natural forests were cleared (Menon and Bawa, 1997; Jha et al., 2000).
The burgeoning human population and decline in the per capita
availability of land have resulted in increased exploitation of natural
resources to a greater extent. The conversion of forest reserve to other
land uses in recent times has resulted in many complex changes in the
forest ecosystem, whose impact raises diverse ecological problems
(Henrik et al., 2010; Awotoye et al., 2013). This destruction of natural
forest from its niche as a result of its conversion has increased the
need to assess the land use changes and their impact on land quality.
Global carbon cycle has gained paramount importance in the recent
decades on account of alarming issues of climate change and global
warming. Soil carbon is one of the components of global C cycle which
plays a pivotal role in mitigating climate change by sequestering
atmospheric carbon. Soil organic carbon pool is influenced by
anthropogenic interventions, which could be by changes in land use or
land cover (Khaledian et al., 2017; Hombegowda et al., 2016; Jaramillo
et al., 2003). Changes in land cover and management practices result in
changes in soil organic carbon stocks (Laganiere et al., 2010; Deng et
al., 2013).
Land use changes such as forest clearing, cultivation and pasture
introduction are also known to result in changes in soil chemical,
physical and biological properties (Houghton et al., 1999), these
changes vary with land cover and land management (Baskin and Binkley
1998; Celik, 2005). Soil physical and chemical properties are proposed
as suitable indicators for assessing the effect of land use changes and
management (Alvarez and Alvarez, 2000) .Assessment of soil properties
upon conversion of natural forests for varying agricultural purposes is
of utmost importance to detect early changes in soil quality (Islam and
Weil, 2000). Several studies have been reported on assessment of C
stocks upon conversion of natural forests to agricultural ecosystems
indicating a decline in C concentration by 20- 50 per cent (Lal, 2005;
Lemenih and Itanna, 2004). However, several physiological attributes of
coffee make it interesting to understand the differences in soil
nutrient status on cultivation of coffee. Coffee is an exhaustive crop
and gives away major part of photosynthates and nutrients through coffee
beans even at the level that may cause exhaustion of the plant (Anil
Kumar et al., 2014). Thus, it becomes important to know how cultivation
of coffee has affected forest soils in terms of soil fertility and land
quality.
To understand the impact of land use changes from forest to coffee
plantations, efforts were made to study and characterize soils from
these ecosystems. The objectives of this study were to assess the
changes in physical and chemical properties of soils with emphasis on
soil organic carbon stocks in response to the land use changes. The
tropical soils of selected study sites are characterized by high
temperature, high and intensive rainfall and permeable soils, which are
vulnerable to sheet erosion.