It disrupts soil structure, accelerating surface runoff and soil erosion. Tillage also reduces crop residue, which help cushion the force of pounding raindrops. Intensive tillage frequently has adverse impact on soil physical quality and soil organic carbon stocks in temperate regions. Nevertheless, conventional tillage exerts many adverse effects, as it contributes to excessive compaction of soils, higher susceptibility of soils to erosion, and accelerated organic matter mineralization. Consequently, long-term conventional tillage may cause loss of soil productivity and fertility. It has been observed that subsoiling tillage treatment can effectively break the plow pan of cultivated land soil, improve soil structure and increase soil porosity and water retention capacity. Tillage practices refer to the soil treatment of arable land carried out between the harvest and the following sowing/cultivation operation. Intensive ploughing and harrowing can have negative environmental impacts, like pesticide and nutrient runoff, soil erosion, soil compaction and loss of organic matters. Each pass of a tillage tool incorporates some residue and thereby reduces the amount of residue on the surface that helps reduce runoff and erosion. Conservation agriculture has proved to be an excellent alternative to conventional agriculture in the long term of sustainable crop production and SOC sequestration.

https://www.sciencedirect.com/science/article/abs/pii/S0341816220306524

Soil and Tillage Research

Volume 80, Issues 1–2, January 2005, Pages 201-213

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Soil organic carbon and nitrogen in a Mollisol in central Ohio as affected by tillage and land use

Author links open overlay panelP. Puget, R. Lal

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https://doi.org/10.1016/j.still.2004.03.018Get rights and content

Abstract

Minimum tillage practices are known for increasing soil organic carbon (SOC). However, not all environmental situations may manifest this potential change. The SOC and N stocks were assessed on a Mollisol in central Ohio in an 8-year-old tillage experiment as well as under two relatively undisturbed land uses; a secondary forest and a pasture on the same soil type. Cropped systems had 51±4 (equiv. mass) Mg ha−1 lower SOC and lower 3.5±0.3 (equiv. mass) Mg ha−1 N in the top 30 cm soil layer than under forest. Being a secondary forest, the loss in SOC and N stocks by cultivation may have been even more than these reported herein. No differences among systems were detected below this depth. The SOC stock in the pasture treatment was 29±3 Mg ha−1 greater in the top 10 cm layer than in cultivated soils, but was similar to those under forest and no-till (NT). Among tillage practices (plow, chisel and NT) only the 0–5 cm soil layer under NT exhibited higher SOC and N concentrations. An analysis of the literature of NT effect on SOC stocks, using meta-analysis, suggested that NT would have an overall positive effect on SOC sequestration rate but with a greater variability of what was previously reported. The average sequestration rate of NT was 330 kg SOC ha−1 year−1 with a 95% confidence interval ranging from 47 to 620 kg SOC ha−1 year−1. There was no effect of soil texture or crop rotation on the SOC sequestration rate that could explain this variability. The conversion factor for SOC stock changes from plow to NT was equal to 1.04. This suggests that the complex mechanisms and pathways of SOC accrual warrant a cautious approach when generalizing the beneficial changes of NT on SOC stocks.

Introduction

Conversion of natural ecosystems to agriculture as well as increasing intensity of tillage are known to decrease soil organic matter (SOM) levels and contribute significantly to the increase in atmospheric CO2 concentration (Lal et al., 1998). Between 1850 and 1995, SOM mineralization emitted 136±55×1015 g of C to the atmosphere (Houghton, 1995, Watson et al., 2001). Changes in SOM by different agricultural land uses and practices have been extensively reviewed by Mann (1986), Davidson and Ackerman (1993), Guo and Gifford (2002), and Murty et al. (2002). Guo and Gifford (2002) reported that soils lost 42 and 59% of their soil organic carbon (SOC) stock upon conversion from forest to crop and from grassland to crop, respectively. In contrast, Mann (1986) calculated losses

Briefly Ashokh, The greater the tillage the less the residual SOM, Paul.

No till has been assessed in a meta analysis by Puget and Lal 2005

Soil organic carbon and nitrogen in a Mollisol in central Ohio as affected by tillage and land use

Author links open overlay panelP. Puget, R. Lal

https://doi.org/10.1016/j.still.2004.03.018Get rights and content

Abstract

Minimum tillage practices are known for increasing soil organic carbon (SOC). However, not all environmental situations may manifest this potential change. The SOC and N stocks were assessed on a Mollisol in central Ohio in an 8-year-old tillage experiment as well as under two relatively undisturbed land uses; a secondary forest and a pasture on the same soil type. Cropped systems had 51±4 (equiv. mass) Mg ha−1 lower SOC and lower 3.5±0.3 (equiv. mass) Mg ha−1 N in the top 30 cm soil layer than under forest. Being a secondary forest, the loss in SOC and N stocks by cultivation may have been even more than these reported herein. No differences among systems were detected below this depth. The SOC stock in the pasture treatment was 29±3 Mg ha−1 greater in the top 10 cm layer than in cultivated soils, but was similar to those under forest and no-till (NT). Among tillage practices (plow, chisel and NT) only the 0–5 cm soil layer under NT exhibited higher SOC and N concentrations. An analysis of the literature of NT effect on SOC stocks, using meta-analysis, suggested that NT would have an overall positive effect on SOC sequestration rate but with a greater variability of what was previously reported. The average sequestration rate of NT was 330 kg SOC ha−1 year−1 with a 95% confidence interval ranging from 47 to 620 kg SOC ha−1 year−1. There was no effect of soil texture or crop rotation on the SOC sequestration rate that could explain this variability. The conversion factor for SOC stock changes from plow to NT was equal to 1.04. This suggests that the complex mechanisms and pathways of SOC accrual warrant a cautious approach when generalizing the beneficial changes of NT on SOC stocks.

Commentary is that no tillage can be used to increase carbon sequestration as increased organic matter in the soil.

The use of cover cropping rotation and compost or manure amendment can also be used alone and togetjher for the same purpose.

Much greater effect can be found with a suite of carbon positive practices are used in systematic practices. Mixed animal and crop farming are particularly powerful of that purpose.