Simulating soil carbon sequestration from long term fertilizer and manure additions under continuous wheat using the DailyDayCent model

K Begum,P Smith,M Kuhnert,M Glendining,J Yeluripati

doi:10.1007/s10705-017-9888-0

Abstract

The widely used ecosystem model DailyDayCent (DDC) was used to predict soil organic carbon (SOC) sequestration and yield under different fertilization treatments on a wheat (Triticum aestivum) monoculture on Broadbalk field, Rothamsted, UK. Over a period of about 170 years, the management practices on the test site, which is separated into plots with different treatments of fertilizer and manure application, are well documented. Four treatments consisting of control (no fertilizer), mineral nitrogen (N) fertilizer (MN), farm yard manure (FYM) and a combination of both (FYMN) have been selected for the study. DDC simulated the greatest increases in SOC (three times higher compared to simulation of the control plot) in the FYM plot. Overall a good agreement between modelled and measured yield was obtained (except in control plots). As observed in the experimental plots, the highest yield predicted by the model is with FYMN plot (more than three times higher relative to the control plot). A sensitivity test for the MN and FYM plots demonstrated that predicted SOC was relatively insensitive (1%) to bulk density, pH and field capacity. Higher sensitivity (4–7%) of predicted SOC changes were observed by changes in external C input. An increase of temperature by 1 °C or precipitation by 10% decreased predicted SOC by 2–4% and vice versa, and simulated a 1–4% variability in yield. DDC is a useful tool for simulating SOC in the long term plots, with a good fit to data, and is useful for examining alternate hypotheses of yield and SOC responses.

Highlights

Soil organic matter (SOM) is an important component in terrestrial ecosystems
90% of the total mitigation potential in the agricultural sector could be derived from soil organic carbon (SOC) sequestration, with about 10% from reduction of non-CO2 greenhouse gases (Smith et al 2007)
The modelled SOC showed a good fit with the measured data (Fig. 2), which is supported by a low values (RMSE \ 10%) in the error analysis (Table 2)

Summary

Introduction

Soil organic matter (SOM) is an important component in terrestrial ecosystems. Beside its significant role in nutrient availability, soil resilience, water holding capacity and crop productivity (Lal 2013; Smith et al 1996), SOM plays a key role in mitigating climate change by capturing atmospheric carbon dioxide (CO2), an important radiatively active gas emitted mainly by anthropogenic activities (Alexander et al 2015; Smith et al 1996). 90% of the total mitigation potential in the agricultural sector could be derived from soil organic carbon (SOC) sequestration, with about 10% from reduction of non-CO2 greenhouse gases (Smith et al 2007). Article 3.4 of the Kyoto Protocol includes agricultural management practices as a potential carbon (C) sink to mitigate climate change impact (Smith 2004), and many Nationally Determined Contributions submitted by parties to the United Nations Framework Convention on Climate Change, as part of the Paris Climate Agreement, include soil C sequestration. The complexity of soil C dynamics, and slow changes of SOC, mean that computer models are a powerful option for simulating and predicting SOC change in different fertilization experiments over long time scales (Powlson 1996). Powlson et al (2012) recently presented SOC changes with RothC at this site, and Falloon and Smith (2000) studied SOM turnover using RothC and CENTURY. Powlson et al (2014) investigated the reason for comparatively lower yield in continuous wheat section relative to wheat rotation, and found impacts of ‘adverse’ weather, which sometimes leads to very late sowing due to saturation of the soil when the original planting time was planned, or susceptibility to disease of the wheat variety used

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Results

Conclusion