Ecosystem Services and Tropical Soils of India by D. K. Pal

Author:D. K. Pal
Language: eng
Format: epub
ISBN: 9783030227111
Publisher: Springer International Publishing

Keywords

Soil inorganic carbon (SIC)SIC stock of Indian SAT soilsLess productive Indian SAT soilsRole of SIC as ecosystem engineersResilience of sodic soils

4.1 Introduction

In the past postglacial period in particular, soils in many parts of the world witnessed climatic fluctuations in response to the global climatic events during the Quaternary. In this geological period, climate changes were also frequent (Ritter 1986). The Indian sub-continent similarly experienced climate change from humid to semi-arid tropical (SAT) in the peninsular as well as extra-peninsular regions during the Holocene (Pal et al. 2003a, 2009a, b, 2012a). It is quite likely that due to this climate shift, parts of India might experience adverse changes in physical and chemical properties of soils (Brevik 2012). Detailed studies on Indian soil types (shrink-swell, red ferruginous and Indo-Gangetic Alluvial soils) and elsewhere in the world (Lal and Kimble 2000a, b; Breecker et al. 2009; Hua 2011) indicate that the dry climate (arid and SAT climates) is the primary factor responsible for the formation of calcareous soils (Pal et al. 2000; Bhattacharyya et al. 2004; Breecker et al. 2009; Srivastava et al. 2013).

Calcareous soils have CaCO3 content which may vary from a small amount in some part of the soil profile to an appreciable amount occurring throughout the profile (Seatz and Peterson 1964). At times, it occupies much of the soil mass in the thick calcic or petrocalcic horizons. During soil examination in the field, it is recognized through its reaction with HCI. However, reaction to HCI does not distinguish the CaCO3 in soils formed through the action of several modes of genesis such as fluvial, lacustral, pedogenic and groundwater (Dhir 1995).

Despite the availability of various estimates of the world storage of SOC, there has been very little effort to estimate the carbon stored in inorganic form, primarily as pedogenic CaCO3. Efforts have, however, been made to estimate the SIC stock in desert soils and in the soils of the world generally (Batjes 1996). The soils that store large quantities of carbonates play an important role in global carbon cycle (Lal and Kimble 2000a, b). In the Indian sub-continent, an estimated area of calcareous soils is 228.8 m ha and covers 69.4% of the total geographical area (TGA) and spreads over 38 out of 60 agro-ecological subregions (AESRs) (Pal et al. 2000). With the availability of broader datasets of soils (NAIP-C-4; http://​www.​geosis-naip-nbsslup.​org/​), a revised map of calcareous soils to identify areas where inorganic C was sequestered has been made available (Bhattacharyya et al. 2014). It is to be noted that SIC stock (33.94Pg) in the first 0–1.5-m-depth Indian soils has more than SOC stock (29.92Pg) (Bhattacharyya et al. 2000). But the SIC stock is mainly due to pedogenic formation of CaCO3 (PC) in SAT soils, which may have adverse effect on soils’ productivity (Pal et al. 2000). However, in the first 0–0.3 m depth, the SOC stock is more than double (9.55Pg) than SIC(4.14Pg), suggesting that shallow-rooted agricultural crops might be adding OC concentration in the rooting zones by preventing the rise of PC, which is an important factor in rainfed agriculture in SAT environments.

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