Soil organic matter and glomalin-related soil protein contents do not explain soil aggregate stability after freeze-thaw cycles at contrasting soil moisture contents

The influence of organic matter amendments on soil aggregate stability is well known, but the corresponding changes in recently deposited sediment are not well documented. In this study, improvements in aggregate stability of recently deposited sediment (RDS) supplemented with farmyard manure (FYM) and tea waste (TW) were evaluated during an 18-week incubation period under controlled conditions. FYM and TW were applied to RDS at different rates (0%, 2.5%, 5%, 7.5%, 10%, 12.5% and 15% w/w), and aggregate stability was determined at different times of incubation (2nd, 4th, 6th, 8th, 10th, 14th, and 18th weeks) using wet sieving analysis. The results showed that the aggregate stability of RDS treated with TW was statistically significantly higher than those of samples treated with FYM. Aggregate stability increased with increasing rates of both FYM and TW. Aggregate stability reached the highest value at the end of the second week in FYM treated samples, and declined within the following incubation period. However, in the samples treated with TW, aggregate stability reached the highest value at the end of the eighth week. Since the results of this study clearly indicated that tea waste and farmyard manure input significantly increased the aggregate stability of RDS, it is suggested that TW and FYM could be used for structural stabilization of degraded soils.

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Comparison of aggregate stability within six soil profiles under conventional tillage using various laboratory tests

Biologia ◽

10.2478/s11756-009-0095-6 ◽

2009 ◽

Vol 64 (3) ◽

Cited By ~ 21

Author(s):

Radka Kodešová ◽

Marcela Rohošková ◽

Anna Žigová

Keyword(s):

Organic Matter ◽

Soil Aggregates ◽

Organic Matter Content ◽

Aggregate Stability ◽

Clay Content ◽

Soil Aggregate ◽

Matter Content ◽

The Other ◽

Structure Stability ◽

Soil Aggregate Stability

AbstractSoil structure stability was studied in every diagnostic horizons of six soil types (Haplic Chernozem, Greyic Phaeozem, two Haplic Luvisols, Haplic Cambisol, Dystric Cambisol) using different techniques investigating various destruction mechanisms of soil aggregates. Soil aggregate stability, assessed by the index of water stable aggregates (WSA), varied depending on the organic matter content, clay content and pHKCl. The presence of clay and organic matter coatings and fillings, and presence of iron oxides in some soils increased stability of soil aggregates. On the other hand periodical tillage apparently decreased aggregate stability in the Ap horizons. Coefficients of aggregate vulnerability resulting from fast wetting (KV 1) and slow wetting (KV 2) tests showed similar trends of the soil aggregate stability as the WSA index, when studied for soils developed on the similar parent material. There was found close correlation between the WSA index and the KV 1 value, which depended also on the organic matter content, clay content and pHKCl. Less significant correlation was obtained between the WSA index and the KV 2 value, which depended on the organic matter content and clay content. Coefficients of vulnerability resulting from the shaking after pre-wetting test (KV 3) showed considerably different trends in comparison to the other tests due to the different factors affecting aggregate stability against the mechanical destruction. The KV 3 value depended mostly on cation exchange capacity, pHKCl and organic matter content.

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Accumulation of glomalin-related soil protein benefits to soil carbon sequestration with tropical coastal forest restoration

10.22541/au.161340180.00516553/v1 ◽

2021 ◽

Author(s):

Jing Zhang ◽

Jian Li ◽

Lingling Ma ◽

Xinhua He ◽

Zhanfeng Liu ◽

...

Keyword(s):

Mycorrhizal Fungi ◽

Forest Restoration ◽

Aggregate Stability ◽

Soil Aggregate ◽

Tropical Region ◽

Native Forest ◽

Barren Land ◽

Soil C ◽

Soil Aggregate Stability ◽

Soil Protein

Reforestation is widely used to restore degraded infertile soils in the coastal area. Substantial attention has been paid to the functioning of AMF in vegetation restoration because arbuscular mycorrhizal fungi (AMF) are considered beneficial to this process. However, little is known about the effect of AMF product, glomalin-related soil protein (GRSP), on soil organic carbon (SOC) sequestration during the forest restoration. We conducted a study in a tropical region where the native forest has been seriously deforested with only a few grasses and then a series of restoration approaches have been made to restore the forest ecosystem. The study sites include a barren land (BL), a Eucalyptus exserta planted forest (EF), a mixed broadleaved forest (MF) and a secondary natural forest (SF), which represents the un-, early-, middle- and late-restoration stage, respectively. The results showed that the restoration increased EE-GRSP and T-GRSP by 3.9-12.3 times and 1.9-4.6 times compared with the barren land, respectively. The proportion of GRSP in SOC is 1.6-2.0% (EE-GRSP/SOC) and 6.5-15.8% (T-GRSP/SOC), respectively. Also, a significantly positive relationship was found between the proportion of GRSP in SOC and recalcitrant SOC composition percentage (aromatic C), as well as between GRSP and soil aggregate stability. These results together suggest that the restoration of the degraded tropical forest is beneficial to soil C sequestration with the accumulation of GRSP, most likely, through an improvement of the soil aggregate stability and increase of the proportion of recalcitrant soil C chemical composition.

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