Response of boreal clay soil properties and erosion to ten years of no-till management

Henri Honkanen,Eila Turtola,Riitta Lemola,Jaakko Heikkinen,Visa Nuutinen,Risto Uusitalo,Janne Kaseva,Kristiina Regina

doi:10.1016/j.still.2021.105043

Henri Honkanen, Eila Turtola + Show 6 more

Open Access

https://doi.org/10.1016/j.still.2021.105043

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Abstract

We compared soil physical, chemical and biological properties, erosion rate and carbon allocation to soil physical fractions between conventional tillage (CT) and no-till (NT) management at a clay soil site under spring cereal monoculture in southwestern Finland. Subsurface drain discharge, surface runoff and soil erosion were continuously monitored in 2008 − 2018. At the end of the 10-year monitoring period in 2018, various soil properties and earthworm total density, mass and species richness were determined. Total soil erosion was 56 % less in NT than in CT although surface water discharge was higher in NT. NT had a clear effect on the topsoil physical structure by decreasing the pore size and increasing soil aggregate size. The total soil carbon stock in the 700 kg m−2 mineral topsoil layer (approx. 0−60 cm layer) was slightly lower in NT (108 ± 12 Mg C ha-1) than in CT (118 ± 9.0 Mg C ha-1) due to lower carbon content of the 10−30 cm layer in NT. In NT the proportion of large macroaggregates was higher and more organic carbon was bound to large macroaggregates in the 0−10 cm layer which may be related to the higher abundance of earthworms in NT. The results showed that NT is an effective method to reduce erosion rates but other means to increase carbon input especially below the topsoil layer are likely required to achieve a significant increase in the carbon stock of boreal clay soils. For both tillage managements, the rate of erosion through subsurface drains depended clearly on annual precipitation and winter temperature, posing a challenge in the future climate with mild winters and more extreme discharges.

Highlights

Agricultural practices conserving soil and its functions are crucial to secure food production and to diminish its environmental impact (Lal, 2004)
There was no significant difference in the soil organic carbon (SOC) content of the 0− 10 cm soil layer between NT and conventional tillage (CT) but the SOC content of the 10− 30 cm layer was lower in NT (Table 1)
The SOC stock calculated for equivalent soil masses was higher in NT compared to CT only in the layer

Summary

Introduction

Agricultural practices conserving soil and its functions are crucial to secure food production and to diminish its environmental impact (Lal, 2004). NT practice reduces farm workload and fuel use and has beneficial environmental impacts like effective reduction of erosion risk (Nearing et al, 2017; Skaalsveen et al, 2019) due to improved soil structure and continuous plant cover (Seta et al, 1993; Skaalsveen et al, 2019). NT has been found to improve soil structure and soil organic carbon (SOC) content of the topsoil, water retention, plant available water capacity and soil biodiversity (Du et al, 2013; Blanco-Canqui and Ruis, 2018). NT potentially decreases water discharge through the soil profile as it im proves soil water retention e.g. through increased organic matter con tent (Rawls et al, 2003) and due to decreased pore size (Chan and Govindaraju, 2004), subsurface discharge is seldom monitored in field experiments

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