Stratification and Storage of Soil Organic Carbon and Nitrogen as Affected by Tillage Practices in the North China Plain.

Xin Zhao,Hai-Lin Zhang,Fan-Lei Kong,Jian-Fu Xue,Fu Chen,Rattan Lal,Xiang-Qian Zhang,Wenju Liang

doi:10.1371/journal.pone.0128873

Abstract

Tillage practices can redistribute the soil profiles, and thus affects soil organic carbon (SOC), and its storage. The stratification ratio (SR) can be an indicator of soil quality. This study was conducted to determine tillage effects on the profile distribution of certain soil properties in winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) systems in the North China Plain (NCP). Three tillage treatments, including no till (NT), rotary tillage (RT), and plow tillage (PT), were established in 2001 in Luancheng County, Hebei Province. The concentration, storage, and SR of SOC and soil total nitrogen (TN) were assessed in both the wheat and maize seasons. Compared with RT and PT, the mean SRs for all depth ratios of SOC under NT increased by 7.85% and 30.61% during the maize season, and by 14.67% and 30.91% during the wheat season, respectively. The SR of TN for 0–5:30–50 cm increased by 140%, 161%, and 161% in the maize season, and 266%, 154%, and 122% in the wheat season compared to the SR for 0–5:5–10 cm under NT, RT and PT, respectively. The data indicated that SOC and TN were both concentrated in the surface-soil layers (0–10 cm) under NT but were distributed relatively evenly through the soil profile under PT. Meanwhile, the storage of SOC and TN was higher under NT for the surface soil (0–10 cm) but was higher under PT for the deeper soil (30–50 cm). Furthermore, the storage of SOC and TN was significantly related to SR of SOC and TN along the whole soil profile (P<0.0001). Therefore, SR could be used to explain and indicate the changes in the storage of SOC and TN. Further, NT stratifies SOC and TN, enhances the topsoil SOC storage, and helps to improve SOC sequestration and soil quality.

Highlights

Soil quality is the capacity to realize the functions of a specific type of soil, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation [1]
A long-term experiment was conducted to assess the changes in soil organic carbon (SOC) and total nitrogen (TN) and their storage and stratification ratio in relation to tillage systems and to document the effect of tillage on the soil quality in the North China Plain (NCP)
The concentrations of SOC and TN decreased with increased soil depth, but an opposite trend was observed in their stratification ratio (SR) at both the wheat and maize harvests

Summary

Introduction

Soil quality is the capacity to realize the functions of a specific type of soil, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation [1]. Farm-management strategies can deteriorate, stabilize or improve soil-ecosystem functions and influence soil quality [2]. Soil organic matter (SOM) is a key indicator that impacts soil quality as well as the crop growth and production [2,3,4]. The concentration of SOM in the soil surface plays vital roles in erosion control, the conservation of nutrients, water infiltration and other important soil functions [2]. Soil organic carbon (SOC) sequestration, which impacts soil quality, is an important strategy to mitigate climate change and improve crop production [5,6,7]. Soil surface SOM and SOC sequestration is crucial to soil quality and agricultural productivity

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