scholarly journals Supplementary material to "Changes in soil physicochemical properties and bacterial communities among different soil depths after long-term straw mulching under a no-till system"

Author(s):  
Zijun Zhou ◽  
Zengqiang Li ◽  
Kun Chen ◽  
Zhaoming Chen ◽  
Xiangzhong Zeng ◽  
...  
SOIL ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 595-609
Author(s):  
Zijun Zhou ◽  
Zengqiang Li ◽  
Kun Chen ◽  
Zhaoming Chen ◽  
Xiangzhong Zeng ◽  
...  

Abstract. Conservation tillage has attracted increasing attention over recent decades, mainly due to its benefits for improving soil organic matter content and reducing soil erosion. However, the effects of long-term straw mulching under a no-till system on soil physicochemical properties and bacterial communities at different soil depths are still unclear. In this 12-year experiment of straw removal (CK) and straw mulching (SM) treatments, soil samples were collected at 0–5, 5–10, 10–20, and 20–30 cm soil depths. The results showed that the contents of organic carbon (C), nitrogen (N), and phosphorus (P) fractions, and bacterial abundance significantly decreased, whereas pH significantly increased with soil depth. Compared with CK, SM significantly increased total N, inorganic N, available P, available potassium, and soil water content at 0–5 cm, total organic C content at 0–10 cm, and dissolved organic C and N contents at 0–20 cm. Regarding bacterial communities, SM increased the relative abundances of Proteobacteria, Bacteroidetes, and Acidobacteria but reduced those of Actinobacteria, Chloroflexi, and Cyanobacteria. Bacterial Shannon diversity and Shannon's evenness at 0–5 cm were reduced by SM treatment compared to CK treatment. Furthermore, SM increased the relative abundances of some C-cycling genera (such as Terracidiphilus and Acidibacter) and N-cycling genera (such as Rhodanobacter, Rhizomicrobium, Dokdonella, Reyranella, and Luteimonas) at 0–5 cm. Principal coordinate analysis showed that the largest difference in the composition of soil bacterial communities between CK and SM occurred at 0–5 cm. Soil pH and N and organic C fractions were the major drivers shaping soil bacterial communities. Overall, SM treatment is highly recommended under a no-till system because of its benefits to soil fertility and bacterial abundance.


2021 ◽  
Author(s):  
Zijun Zhou ◽  
Zengqiang Li ◽  
Kun Chen ◽  
Zhaoming Chen ◽  
Xiangzhong Zeng ◽  
...  

Abstract. Conservation tillage has attracted increasing attention over recent decades, mainly due to its benefits in improving soil organic matter content and reducing soil erosion. Under intensive conventional tillage systems, some studies have focused on the responses of soil properties in the topsoil to straw retention. However, long-term straw mulching effects on soil physicochemical properties and bacterial communities among different soil depths under a no-till system are still obscure. One twelve-year experiment was conducted that included straw removal (CK) and straw mulching (SM) treatments. Soil samples were collected at 0–5, 5–10, 10–20, and 20–30 cm soil depths. Most soil physicochemical properties and the relative abundances of bacterial phyla were varied with soil depth. Compared with CK, SM increased soil total nitrogen and organic carbon, available phosphorus and potassium, dissolved organic carbon and nitrogen, and water content. SM increased soil bacterial abundance but reduced the Shannon diversity of the bacterial community at 0–5 cm depth. SM increased the relative abundances of Proteobacteria, Bacteroidetes, and Acidobacteria but reduced those of Actinobacteria, Chloroflexi, and Cyanobacteria. SM had different effects on the relative abundances of some C- and N-cycling genera, for instance, increasing Rhodanobacter, Rhizomicrobium, and Terracidiphilus, and reducing Anaeromyxobacter, Mycobacterium, and Syntrophobacter. A principal coordinate analysis indicated that SM largely affected soil bacterial communities at topsoil depth. Soil pH and different nitrogen and organic carbon fractions were the major drivers shaping soil bacterial community. Overall, straw mulch is highly recommended for use under a no-till system because of its benefits to soil fertility and bacterial abundance. However, inorganic nitrogen fertilizer levels may be reduced under straw mulching to maintain or increase soil bacterial Shannon diversity in future studies.


2017 ◽  
Vol 83 (22) ◽  
Author(s):  
Daniel C. Schlatter ◽  
Chuntao Yin ◽  
Scot Hulbert ◽  
Ian Burke ◽  
Timothy Paulitz

ABSTRACT Glyphosate is the most widely used herbicide worldwide and a critical tool for weed control in no-till cropping systems. However, there are concerns about the nontarget impacts of long-term glyphosate use on soil microbial communities. We investigated the impacts of repeated glyphosate treatments on bacterial communities in the soil and rhizosphere of wheat in soils with and without long-term history of glyphosate use. We cycled wheat in the greenhouse using soils from 4 paired fields under no-till (20+-year history of glyphosate) or no history of use. At each cycle, we terminated plants with glyphosate (2× the field rate) or by removing the crowns, and soil and rhizosphere bacterial communities were characterized. Location, cropping history, year, and proximity to the roots had much stronger effects on bacterial communities than did glyphosate, which only explained 2 to 5% of the variation. Less than 1% of all taxa were impacted by glyphosate, more in soils with a long history of use, and more increased than decreased in relative abundance. Glyphosate had minimal impacts on soil and rhizosphere bacteria of wheat, although dying roots after glyphosate application may provide a “greenbridge” favoring some copiotrophic taxa. IMPORTANCE Glyphosate (Roundup) is the most widely used herbicide in the world and the foundation of Roundup Ready soybeans, corn, and the no-till cropping system. However, there have been recent concerns about nontarget impacts of glyphosate on soil microbes. Using next-generation sequencing methods and glyphosate treatments of wheat plants, we described the bacterial communities in the soil and rhizosphere of wheat grown in Pacific Northwest soils across multiple years, different locations, and soils with different histories of glyphosate use. The effects of glyphosate were subtle and much less than those of drivers such as location and cropping systems. Only a small percentage of the bacterial groups were influenced by glyphosate, and most of those were stimulated, probably because of the dying roots. This study provides important information for the future of this important tool for no-till systems and the environmental benefits of reducing soil erosion and fossil fuel inputs.


Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1167
Author(s):  
Qiuyue Liu ◽  
Zhengrong Kan ◽  
Cong He ◽  
Hailin Zhang

No-till (NT) practice has been widely adopted to improve soil quality, but soil compaction and soil organic carbon (SOC) stratification under long-term NT limit crop production. Strategic tillage (ST), based on single tillage, is proposed as an attractive management practice to sustain the benefits of continuous NT and mitigate its adverse effects. Four tillage systems, including continuous rotary tillage (RT), NT, rotary tillage + subsoiling (RS), and no-till + subsoiling (NS), were implemented to investigate the effects of strategic tillage (i.e., RS and NS) on soil physical properties (compaction and aggregates), SOC, and crop yield in the North China Plain (NCP). The results showed that ST as expected decreased soil bulk density, penetration resistance, and SOC stratification compared with RT and NT at 0–20 cm soil depth (p < 0.05). At 0–10 cm soil depth, more macroaggregates (>0.25 mm) were observed in NT and NS, contributing to higher mean weight and geometric mean diameters, this compared with RT and RS. Additionally, macroaggregate associated SOC was higher, thus resulting in higher SOC storage in NT (31.4–33.4 Mg ha −1) and NS (33.3–35.4 Mg ha−1) at 0–30 cm depth (p < 0.05). Low soil compaction and high SOC in NS were beneficial for the grain yield of wheat and maize, significantly higher by 8.7–32.5% and 14.0–29.8% compared with the other treatments, respectively (p < 0.05). Based on our findings, NS seems to be a promising alternative tillage system to improve soil physicochemical properties and crop production in the NCP. More studies are therefore needed to better understand the benefit of NS.


Soil Systems ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 7 ◽  
Author(s):  
Ricky Lewis ◽  
Victoria Barth ◽  
Todd Coffey ◽  
Carol McFarland ◽  
David Huggins ◽  
...  

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