AUTHOR=Ghosh Tridiv , Maity Pragati Pramanik , Das T. K. , Krishnan P. , Chakraborty Debashis , Bhatia Arti , Ray Mrinmoy , Kundu Aditi , Bhattacharyya Ranjan 

TITLE=Characterization of Soil Pores Through X-Ray Computed Microtomography and Carbon Mineralization Under Contrasting Tillage and Land Configurations in the Indo-Gangetic Plains of India

JOURNAL=Frontiers in Environmental Science

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2022.898249

DOI=10.3389/fenvs.2022.898249

ISSN=2296-665X

ABSTRACT= Contrasting tillage and land configuration has important role in porosity and pore size distribution (PSD) and which in turn affects the carbon mineralization in soil. Information on effects of these treatments on PSD and subsequent carbon mineralization is very limited.  Hence, an attempt was made to evaluate the long-term impact of soil tillage and land configurations on the distribution of soil pores and its relationship to soil carbon mineralization under a maize (Zea mays)- wheat (Tritiacum aestivum) rotation. There were five treatments i.e. conventional tillage, CT; permanent broad bed, PBB; PBB + R (residue), zero tillage, ZT and ZT + R (residue). Soil pores were quantified using X-ray computed tomography (μ-CT). Conversion of (CT) to zero tillage (ZT) and permanent broad bed (PBB) with residue retention (+R) or without residue retention resulted in reduction of pores >60 μm diameter and was mostly due to a reduction in the numbers of larger size macropores(>110 μm). This resulted in restricted drainage. However, under these practices, pores with larger diameters (60-110 μm) facilitated soil aeration. Total organic carbon (TOC) was 15-48 and 17- 47% higher under PBB, PBB+R, ZT and ZT+R than that under CT in the 0-5 and 5-15 cm layers. Highest MWD (1.01 mm) was in the plots under PBB + R and lowest was in the CT plots and all residue retained plots (ZT+R and PBB+R) had higher MWD than residue removal plots (ZT and PBB).  Relative to CT, soil C mineralization rates in the  0-5 and 5-15 cm soil depths were 63 and 55% higher in the  alternate tillage practices and the highest value occurred in  PPB+R treatments. Increased labile C concentrations were indicative of greater mineralization and were correlated with pores >60 μm, particularly in the size range 110-500 μm and TOC concentrations (of 0-15 cm soil layer). Thus, transition to alternate tillage from the conventional tillage, enhanced soil organic carbon concentration (16-47.5%), improved soil structure, reduction of pores >60 μm diameter and facilitated C-mineralization by altering the pore size distribution of soil under a maize-wheat system in the IGP.