Changes in Soil Aggregate-Associated Organic Carbon and Nitrogen after Ten Years under Different Land-Use and Soil-Management Systems in Indo-Gangetic Sodic Soil

Abstract

A study was conducted to evaluate the effects of different land uses and soil-management systems (LU and SMS) on key soil physicochemical indicators [aggregate stability, distribution of soil organic carbon (SOC), and nitrogen (N) in aggregate fractions] and to interpret significance of long-term cultivation of agroforestry plantations [Prosopis juliflora L. (AFP) and Casuarina equisetifolia L. (AFC)], horticultural plantations [(Tamarindus indica (HI) and Syzygium cumini (HJ)], and rice–wheat system (RW) in sodic soil of the Indo-Gangetic plain. Soil samples collected from the different LU and SMS plots were analyzed. The barren sodic soil (BSS) exhibited the least mean weight aggregate diameter (0.21), whereas AFP recorded the greatest (0.59). Total N content in surface soil under RW system was about the same as AFP, AFC, HI, and HJ and significantly greater than BSS. Across the LU and SMS except BSS, microaggregates recorded a narrower C/N ratio than macro- and mesoaggregates.