Micromorphological analysis of soil structure under no tillage management in the black soil zone of Northeast China

Abstract

The structure of the "black soil" in Northeast China has been greatly deteriorated by long-term intensive conventional mouldboard plow tillage (CT) practices. In this study, micromorphological observation and image analysis of soil thin sections were conducted to evaluate the impacts of 21 years of no tillage (NT) on soil structure as compared to CT in an experiment near Gongzhuling City, Jilin Province. Soil organic matter (SOM), wet aggregate stability and saturated hydraulic conductivity (Ks) were also analyzed. Total SOM was not significantly affected by tillage systems, but fresher SOM was observed in the surface layer under NT. The aggregates under NT showed different hierarchies in the form of crumbs, and the mean weight diameter (MWD) of NT was significant higher than that of CT in the surface layer. Platy and blocky aggregates were frequently observed in the lower layers under CT practice. The compound pore structure with intertwined intra-and interaggregates pores under NT was well developed in a layer from 0-5 cm to 20-25 cm. While under CT system, more inter-aggregate pores and fewer intraaggregate pores were observed, and planes and channels were frequently found in the 20-25 cm layer, where macroporosity decreased significantly and a plow pan was evident. The Ks values of NT were significantly lower at 0-5 cm but significantly higher at 20-25 cm compared with CT, which showed the same trend with macroporosity. These results confirmed that long-term CT practice fragmented the tillage layer soil and compacted the lower layer soil and formed a plow pan. While long-term NT practice in the black soil region favored soil aggregation and a stable porous soil structure was formed, which are important to the water infiltration and prevent soil erosion.

Quantitative evaluation of pore characteristics of sodic soils reclaimed by flue gas desulphurization gypsum using X‐ray computed tomography

“…However, the current thresholding methods reported for sodic soils are very limited. Therefore, the best visual inspection method was used to perform the segmentation of image, which has been recognized effective in many published reports (Luo et al, , Luo, Lin, & Li, , Luo, Lin, & Schmidt, ; Marcelino et al, ; Zhou et al, , Zhou et al, ). Moreover, this method has been valid to be feasible in segmentation of CT images of sodic soils in our previous similar study (Yu et al, ).…”

“…The parameters including volume, length, surface area, and spatial form of 3D pores can be extracted using the Avizo Fire 7 software. In this study, all 3D image‐based pores were hypothesized as cylindrical because there is no theoretical ‘standard' of definition of pores in 3D (Luo, Lin, & Li, , Luo, Lin, & Schmidt, ; Zhou, Li, & Lu, ), and the pores were defined as ‘micropore' (<100 μm), ‘mesopore' (100–500 μm), or ‘macropore' (>500 μm) based on their equivalent cylindrical diameter. Then we calculated the 3D image‐based volume and number of pores.…”

Soil Organic Carbon Loss and Selective Transportation under Field Simulated Rainfall Events

“…However, most of the researches, under different rainfall intensities and tillage practices, focused on the SOC dynamics during erosion, were conducted in watershed [16] – [18] or laboratory [10] , [13] , [19] . Different points of view were observed between them for the variety of research conditions.…”

Tillage effects on soil properties and crop yield after land reclamation

“…After land reclamation, the soil structure of the newly reclaimed cultivated land is unstable and relatively fragile 5 . Inappropriate single tillage treatment can cause soil particles to migrate and settle, accelerate the nutrients mineralization and depletion, reduce the number and structural stability of aggregates and disrupt surface vented pores, resulting in the compaction of lower layer soil and the formation of plow pan 24 . Due to soil compaction and settling, the physical and chemical properties and crop growth will be greatly affected.…”