No Tillage Increases SOM in Labile Fraction but Not Stable Fraction of Andosols from a Long-Term Experiment in Japan

Jeannette Aduhene-Chinbuah,Masakazu Komatsuzaki,Haruo Tanaka,Soh Sugihara,Tomoyasu Nishizawa

doi:10.3390/agronomy12020479

Jeannette Aduhene-Chinbuah, Masakazu Komatsuzaki + Show 3 more

Open Access

https://doi.org/10.3390/agronomy12020479

Copy DOI

Abstract

No tillage (NT) fosters carbon (C) sequestration, increases soil organic matter (SOM) stock, and improves soil health. However, its effect on SOM accumulation in Andosol, which has high OM stabilization characteristics due to its specific mineral properties, remains unclear. In this study, we evaluated the effect of NT on SOM content and its distribution by the physical fractionation method and assessed the quality of accumulated SOM in each fraction. We collected soil samples at 0–2.5, 2.5–7.5, and 7.5–15 cm depths from NT and conventional tillage (CT) plots in a long-term (19 years) field experiment of Andosols in Ibaraki, Japan. The soil samples were separated into light fraction (LF), coarse-POM (cPOM: 0.25–2 mm), fine-POM (fPOM: 0.053–0.25 mm), and silt + clay (mOM: <0.053 mm). The C, nitrogen (N), and organic phosphorus (Po) contents of each fraction were analyzed. The C content of cPOM and fPOM in NT at 0–7.5 cm was higher than in CT, while there was no clear difference in the mOM fraction or deeper layer (7.5–15 cm). NT increased the C, N, and Po contents in the labile POM fractions at the surface layers but did not increase the stable fraction or change the quality.

Highlights

IntroductionSoil organic matter (SOM) has a significant influence on many soil functions (i.e., physical, chemical, and biological) and stores nutrients (carbon (C), nitrogen (N), phosphorus (P), etc.), which are gradually released into the soil by mineralization for plant uptake [1]
The Po concentration of mineral-associated organic matter (mOM) at the 7.5–15 cm depth was higher in No tillage (NT) than in conventional tillage (CT), while that of cPOM and fPOM was lower in NT than in CT (Figure 2i)
This study revealed an increase in the Total Carbon (TC), Total Nitrogen (TN), and Po contents of cPOM and fPOM

Summary

Introduction

Soil organic matter (SOM) has a significant influence on many soil functions (i.e., physical, chemical, and biological) and stores nutrients (carbon (C), nitrogen (N), phosphorus (P), etc.), which are gradually released into the soil by mineralization for plant uptake [1]. The management of SOM amounts in soil is crucial to soil fertility and crop yield as well as in climate change mitigation [2,3,4,5]. The management of SOM is key to soil functioning worldwide [6]. No tillage (NT) has been found to play an essential role in SOM accumulation [7,8] by reducing surface soil disturbance. NT is considered a promising technique for sustainable SOM management, which includes the sequestration of C for climate change mitigation and sustainable soil fertility

Objectives

Methods

Results

Discussion

Conclusion