scholarly journals Rice-husk biochar effects on organic carbon, aggregate stability and nitrogen-fertility of coarse-textured Ultisols evaluated using Celosia argentea growth

2021 ◽  
Vol 18 (2) ◽  
pp. 177
Author(s):  
Nancy E. Ebido ◽  
Ifeoma G. Edeh ◽  
Benedict O. Unagwu ◽  
Ogorchukwu V. Ozongwu ◽  
Sunday Ewele Obalum ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Plant Height ◽  
Aggregate Stability ◽  
Tropical Soils ◽  
Soil Aggregate ◽  
Soil Aggregate Stability ◽  
Nitrogen Fertility ◽  
Celosia Argentea ◽  
Rice Husk Biochar

There are insufficient data supporting the enormous potential of biochar in highly weathered tropical soils. This glasshouse study assessed rice-husk biochar (RHB) effects on soil organic carbon, aggregate stability and nitrogen fertility of sandy-loam Ultisols which were evaluated using spinach (<em>Celosia argentea</em>) growth. Five RHB rates 0, 5, 10, 20, and 40 g per two-kg-soil (0, 7.5, 15, 30 and 60 t ha<sup>−1</sup>, respectively) were studied under 0, 4, 8, and 12 weeks of incubation (WOI). Batched potting of treatments enabled sowing on one date. Treatment effects on soil quality were assessed at sowing and spinach growth six weeks later. Soil organic carbon generally increased with RHB rate, with the greatest increments (37%) in maximum rate relative to no-biochar control for 8 WOI. Aggregate stability also generally increased with RHB rate, the range being 7.21%-17.21% for 8 WOI, beyond which it decreased in 10 and 20 but not 40 g pot<sup>–1</sup>. Total nitrogen was always highest in maximum rate, increasing with rate only for 8 WOI. Treatment affected plant height more clearly than leaf count. Optimum rates were 5 or 10 g pot<sup>–1</sup> for 8 and 4 WOI, respectively (plant height) and 10 g pot<sup>–1</sup> for 8 WOI (leaf count). Soil organic carbon influenced soil aggregate stability (R<sup>2</sup> = 0.505) which in turn was quadratically related to plant height (R<sup>2</sup> = 0.517), indicating stability threshold for spinach. Adding RHB at 40 g pot<sup>–1</sup> (≈ 60 t ha<sup>−1</sup>) to coarse-textured tropical soils is suggested to sustain its soil aggregating effect beyond the growth phase of short-cycle leafy vegetables which require a lower rate (10 g pot<sup>–1</sup>) 8 weeks before sowing. The observed role of soil aggregate stability in spinach growth rather than the overall effects of RHB should guide further search for edapho-agronomic optimum rate of RHB.

scholarly journals Dynamics of Soil Organic Carbon and Labile Carbon Fractions in Soil Aggregates Affected by Different Tillage Managements

2021 ◽  
Vol 13 (3) ◽  
pp. 1541
Author(s):  
Xiaolin Shen ◽  
Lili Wang ◽  
Qichen Yang ◽  
Weiming Xiu ◽  
Gang Li ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
No Tillage ◽  
Labile Carbon ◽  
Carbon Fractions ◽  
Soil Aggregate Stability ◽  
Positive Effects

Our study aimed to provide a scientific basis for an appropriate tillage management of wheat-maize rotation system, which is beneficial to the sustainable development of agriculture in the fluvo-aquic soil areas in China. Four tillage treatments were investigated after maize harvest, including rotary tillage with straw returning (RT), deep ploughing with straw returning (DP), subsoiling with straw returning (SS), and no tillage with straw mulching (NT). We evaluated soil organic carbon (SOC), dissolved organic carbon (DOC), permanganate oxidizable carbon (POXC), microbial biomass carbon (MBC), and particulate organic carbon (POC) in bulk soil and soil aggregates with five particle sizes (>5 mm, 5–2 mm, 2–1 mm, 1–0.25 mm, and <0.25 mm) under different tillage managements. Results showed that compared with RT treatment, NT treatment not only increased soil aggregate stability, but also enhanced SOC, DOC, and POC contents, especially those in large size macroaggregates. DP treatment also showed positive effects on soil aggregate stability and labile carbon fractions (DOC and POXC). Consequently, we suggest that no tillage or deep ploughing, rather than rotary tillage, could be better tillage management considering carbon storage. Meanwhile, we implied that mass fractal dimension (Dm) and POXC could be effective indicators of soil quality, as affected by tillage managements.

scholarly journals Effects of Soil Aggregate Stability on Soil Organic Carbon and Nitrogen under Land Use Change in an Erodible Region in Southwest China

2019 ◽  
Vol 16 (20) ◽  
pp. 3809 ◽  
Author(s):  
Man Liu ◽  
Guilin Han ◽  
Qian Zhang
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Land Use Change ◽  
Soil Organic Carbon ◽  
Southwest China ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
Soil Erodibility ◽  
Agricultural Abandonment ◽  
Soil Aggregate Stability

Soil aggregate stability can indicate soil quality, and affects soil organic carbon (SOC) and soil organic nitrogen (SON) sequestration. However, for erodible soils, the effects of soil aggregate stability on SOC and SON under land use change are not well known. In this study, soil aggregate distribution, SOC and SON content, soil aggregate stability, and soil erodibility were determined in the soils at different depths along the stages following agricultural abandonment, including cropland, abandoned cropland, and native vegetation land in an erodible region of Southwest China. Soil aggregation, soil aggregate stability, and SOC and SON content in the 0–20 cm depth soils increased after agricultural abandonment, but soil texture and soil erodibility were not affected by land use change. Soil erodibility remained in a low level when SOC contents were over 20 g·kg−1, and it significantly increased with the loss of soil organic matter (SOM). The SOC and SON contents increased with soil aggregate stability. This study suggests that rapidly recovered soil aggregate stability after agricultural abandonment promotes SOM sequestration, whereas sufficient SOM can effectively maintain soil quality in karst ecological restoration.

Medium-term Effects of Mineral Fertilizer and Organic Amendments on Aggregate and Soil Organic Carbon and Nitrogen Dynamics in Rhizosphere and Bulk Soil

2021 ◽  
Author(s):  
Wenhai Mi ◽  
Taotao Zha ◽  
Qiang Gao ◽  
Haitao Zhao
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Organic Amendments ◽  
Aggregate Stability ◽  
Mineral Fertilizer ◽  
Soil Aggregate ◽  
Bulk Soil ◽  
Medium Term ◽  
Soil Aggregate Stability ◽  
Carbon And Nitrogen

Abstract Soil aggregate stability is one of the important physical properties affecting rice (Oryza sativa L.) production and soil sustainability. This study was undertaken to evaluate the influence of different medium-term fertilization regimes on soil aggregate stability and aggregate associated carbon and nitrogen in rhizosphere and bulk soil. This experiment consisted of three treatments including mineral fertilizer alone (NPK), mineral fertilizer plus rice straw (NPK + RS), and controlled-release blended fertilizer plus cattle manure (CRF + CM). The results showed that bulk soil contained higher mean weight diameter (MWD) than in rhizosphere soil at the rice jointing and maturity stages. Compared to the NPK alone, combined application of NPK with organic amendments improved the proportion of > 0.25 mm macroaggregate, soil organic carbon (SOC), total nitrogen (TN) concentrations, and MWD in both rhizosphere and bulk soil. In rhizosphere, the proportion of macroaggregate was significantly positively (p < 0.01) correlated with root biomass while had no significant correlations with SOC in all sizes aggregates. By contrast, bulk soil had a significantly (p < 0.01) positive relationship between the proportion of > 2 mm class and organic C associated with smaller particle-size aggregates (0.25–2 mm and < 0.25 mm). During the rice-growing season, the highest MWD value was observed at the jointing stage except for the NPK + RS treatment in bulk soil. Overall, the results suggested that the medium-term application of mineral fertilizer with organic amendments is beneficial to improve soil aggregate stability and C and N accumulation.

scholarly journals Effects of organic mulching on soil aggregate stability and aggregate binding agents in an urban forest in Beijing, China

2021 ◽  
Author(s):  
Wei Zhou ◽  
Xiangyang Sun ◽  
Suyan Li ◽  
Tiantian Du ◽  
Yi Zheng ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Urban Forest ◽  
Geometric Mean ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
Wood Chips ◽  
Soil Aggregate Stability ◽  
Mean Weight Diameter ◽  
Soil Protein

AbstractUrban forest soil is often disturbed by rapid urbanization. Organic mulching is effective for improving soil quality and aggregate stability. This study evaluated how soil binding agents changed aggregate stability through organic mulching in urban forest soils. Three treatments were applied in Jiufeng National Forest Park, Beijing: (1) no organic mulch (control); (2) wood chips alone (5 cm thickness); and, (3) wood chips + wood compost (This mulch was divided into two layers, the upper layer of wood chips (2.5 cm), the lower layer wood compost (2.5 cm)). Soil samples were collected from the surface 10- cm soil layer and fraction into four aggregates. Glomalin-related soil protein and soil organic carbon were measured in bulk soil and the four aggregates. The results show that wood chips + wood compost increased the proportion of large and small macroaggregates, mean weight diameter and geometric mean diameter. The total and easily extractable glomalin-related soil protein were higher in the wood chips + wood compost. However, soil organic carbon was lower in the wood chips alone application compared to the controls and wood chips + wood compost. Easily extractable / total glomalin-related soil protein and glomalin-related soil protein / soil organic carbon ratios of wood chips alone and wood chips + wood compost had increased trend compared to the controls but did not reach significant levels (p > 0.05). Mean weight diameter and geometric mean diameter correlated positively with total and easily extractable glomalin-related soil protein but were not positively correlated with soil organic carbon, the ratios of easily extractable and total glomalin-related soil protein, and the ratios of glomalin-related soil protein and soil organic carbon. Redundancy analysis revealed that total glomalin-related soil protein was the most important driver for soil aggregate stability, especially the total glomalin-related soil protein of small macroaggregates. The results suggest that wood chips + wood compost enhanced soil aggregate stability through the increase of glomalin-related soil protein. Wood chips alone cannot enhance soil aggregate stability in urban forests in the short term.

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