Importance of soil interparticle forces and organic matter for aggregate stability in a temperate soil and a subtropical soil

Geoderma ◽  
2020 ◽  
Vol 362 ◽  
pp. 114088 ◽  
Author(s):  
Zhenghong Yu ◽  
Yanyun Zheng ◽  
Jiabao Zhang ◽  
Congzhi Zhang ◽  
Donghao Ma ◽  
...  
2019 ◽  
Vol 37 (3) ◽  
pp. 263-273
Author(s):  
Efraín Francisco Visconti-Moreno ◽  
Ibonne Geaneth Valenzuela-Balcázar

The stability of soil aggregates depends on the organic matter, and the soil use and management can affect the soil organicmatter (SOM) content. Therefore, it is necessary to know therelationship between aggregate stability and the content of SOMin different types of soil use at two different altitudes of theColombian Andes. This study examined the conditions of soilaggregate stability expressed as a distribution of the size classes of stable aggregates (SA) and of the mean weighted diameter of the stable aggregates (MWD). To correlate these characteristics with the soil organic carbon (OC), we measured the particulate organic matter pool (POC), the OC associated with the mineral organic matter pool (HOC), the total organic carbon content (TOC), and the humification rate (HR). Soils were sampled at two altitudes: 1) Humic Dystrudepts in a cold tropical climate (CC) with three plots: tropical mountain rainforest, pastures, and crops; 2) Fluvaquentic Dystrudepts in a warm tropical climate (WC) with three plots: tropical rainforest, an association of oil palm and pastures, and irrigated rice. Soils were sampled at three depths: 0-5, 5-10 and 10-20 cm. The physical properties, mineral particle size distribution, and bulk density were measured. The content of SA with size>2.36 mm was higher in the CC soil (51.48%) than in the WC soil (9.23%). The SA with size 1.18-2.36 mm was also higher in the CC soil (7.78%) than in the WC soil (0.62%). The SA with size 0.60-1.18 mm resulted indifferent. The SA with size between 0.30 and 0.60 mm were higher in the WC soil (13.95%) than in the CC soil (4.67%). The SA<0.30 mm was higher in the WC soil (72.56%) than in the CC soil (32.15%). It was observed that MWD and the SA>2.36 mm increased linearly with a higher POC, but decreased linearly with a higher HR. For the SA<0.30 mm, a linear decrease was observed at a higher POC, while it increased at a higher HR.


2015 ◽  
Vol 7 (1) ◽  
pp. 1007-1024
Author(s):  
B. Turgut

Abstract. The aim of this study was to compare the soils of the wheat cultivation area (WCA) and the safflower cultivation area (SCA) within semi-arid climate zones in terms of their total carbon, nitrogen, sulphur contents, particle size distribution, aggregate stability, organic matter content, and pH values. This study presents the results from the analyses of 140 soil samples taken at two soil layers (0–10 and 10–20 cm) in the cultivation areas. At the end of the study, it has been established that there were significant differences between the cultivation areas in terms of soil physical properties such as total carbon (TC), total nitrogen (TN), total sulphur (TS) contents and pH, while only the TN content resulted in significantly different between the two soil layers. Moreover significant differences were identified in the cultivation areas in terms of soil physical properties including clay and sand contents, aggregate stability and organic matter content, whereas the only significant difference found among the soil layers was that of their silt content. Since safflower contains higher amounts of biomass than wheat, we found higher amounts of organic matter content and, therefore, higher amounts of TN and TS content in the soils of the SCA. In addition, due to the fact that wheat contains more cellulose – which takes longer to decompose – the TC content of the soil in the WCA were found to be higher than that of the SCA. The results also revealed that the WCA had a higher carbon storage capacity.


Soil Research ◽  
1995 ◽  
Vol 33 (6) ◽  
pp. 975 ◽  
Author(s):  
A Golchin ◽  
P Clarke ◽  
JM Oades ◽  
JO Skjemstad

Soil samples were obtained from the surface horizons of five untilled sites and adjacent sites under short- and long-term cultivation. The soil samples were fractionated based on density and organic materials were concentrated in various fractions which enabled comparative chemical composition of the organic materials in cultivated and uncultivated sites by solid-state C-13 CP/MAS NMR spectroscopy. Changes in the nature of organic carbon with cultivation were different in different soils and resulted from variations in the chemistry of carbon inputs to the soils and a greater extent of decomposition of organic materials in cultivated soils. Differences in the chemical composition of organic carbon between cultivated and uncultivated soils resided mostly in organic materials occluded within aggregates, whereas the chemistry of organic matter associated with clay particles showed only small changes. The results indicate a faster decomposition of O-alkyl C in the cultivated soils. Wet aggregate stability, mechanically dispersible clay and modulus of rupture tests were used to assess the effects of cultivation on structural stability of soils. In four of five soils, the virgin sites and sites which had been under long-term pasture had a greater aggregate stability than the cultivated sites. Neither total organic matter nor total O-alkyl C content was closely correlated with aggregate stability, suggesting that only a part of soil carbon or carbohydrate is involved in aggregate stability. The fractions of carbon and O-alkyl C present in the form of particulate organic matter occluded within aggregates were better correlated with aggregate stability (r = 0.86** and 0.88**, respectively). Cultivation was not the dominant factor influencing water-dispersible clay across the range of soil types used in this study. The amount of dispersible clay was a function of total clay content and the percentage of clay dispersed was controlled by factors such as clay mineralogy, CaCO3 and organic matter content of soils. The tendency of different soils for hard-setting and crusting, as a result of structural collapse, was reflected in the modulus of rupture (MOR). The cultivated sites had significantly higher MOR than their non-tilled counterparts. The soils studied had different MOR due to differences in their physical and chemical properties.


2016 ◽  
Vol 6 ◽  
Author(s):  
Bülent Turgut ◽  
Bahtiyar Köse

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 (2<sup>nd</sup>, 4<sup>th</sup>, 6<sup>th</sup>, 8<sup>th</sup>, 10<sup>th</sup>, 14<sup>th</sup>, and 18<sup>th</sup> 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.


2020 ◽  
Vol 150 ◽  
pp. 03010
Author(s):  
Hassnae Maher ◽  
Rachid Moussadek ◽  
Abdelmjid Zouahri ◽  
Ahmed Douaik ◽  
Houria Dakak ◽  
...  

In Morocco, agriculture is an important sector of the economy, accounting for 15 to 20% of Gross Domestic Product. However, it has faced several challenges: intensive tillage of land that has accelerated water erosion, seriously threatening water and soil potential, low plant cover density and misuse of traditional agricultural practices, causing a decrease in organic matter levels and destroying aggregate stability. Climate change is making water and soil management in agriculture more and more complicated. The major challenge for Moroccan agriculture is to increase agricultural production while preserving natural resources. The objective of our study is to evaluate the effect of no tillage (NT) on the physico- chemical properties of soil in the El Koudia experimental station, Rabat, Morocco. The crop is durum wheat, Arrehane variety. Soil samples are pre-dried, ground and screened to 0.2mm for organic matter (OM) analysis and 2mm for the remainder of the analyses. Plugs, canned, are then sintered, screened and dried for structural stability tests. The results show that no tillage (NT) favours the accumulation of surface OM, particularly at the 0-5cm horizon unlike conventional tillage (CT). The NT promotes structural stability, with a mean weight diameter (MWD) = 0.94mm for the NT compared to 0.83mm for the CT. These results show that soils ploughed in CT are more exposed to erosion degradation than soils not ploughed (NT). In addition, NT preserves soil moisture and promotes additional water retention of 5 to 10%.


1970 ◽  
Vol 10 (44) ◽  
pp. 313 ◽  
Author(s):  
J Loveday ◽  
JE Saunt ◽  
PM Fleming ◽  
WA Muirhead

Furrow-irrigated cotton was grown for two seasons on a previously uncultivated dense clay soil to which the following treatments had been applied :--normal ploughing (18 cm), precision ripping (30 cm), deep ploughing (40 cm), deep ripping (60 cm), and deep ploughing and deep ripping combined, with and without applications of gypsum at 10 tons an acre or organic matter at 2 1/2 tons an acre. The deep tillage significantly increased the porosity of the subsoil, but this extra porosity had largely been lost by the end of the second season. Neither the gypsum nor the organic matter addition had a significant effect upon its rate of decline. Despite the effect on porosity the deep tillages had only small and mostly non-significant effects upon water increment at irrigation. The gypsum treatment, but not the organic matter, increased water entry to the subsoil at irrigation, and this W-as apparently a result of improved hydraulic conductivity and aggregate stability, particularly in the surface layers. Considerable leaching of chloride occurred from the 30-60 cm subsoil zone in both gypsum treated and deep-tilled plots, but not in organic matter plots, and an accumulation of chloride occurred in the 0-10 cm layer (the hill) in gypsum treated plots. The increased water intake to the subsoil resulting from gypsum treatment was matched by increased water use in the following period, and hence a reduction in relative water deficit of Leaves during the peak period of water demand. Neither the organic matter nor the deep tillages had appreciable influence on water uptake. Water use during periods of peak demand was about 6 mm a day for gypsum treated plots, and this was probably lower than mould have been obtained with water freely available at all times. On the other treatments it can he inferred that water use was even further reduced by lack of available water.


Solid Earth ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Bülent Turgut ◽  
Merve Ateş

Abstract. The aim of this study was to determine certain basic properties of soils in the Batumi delta (southwestern Georgia) to determine the relationships of studied properties and to identify differences with regards to these properties between different sampling sites in the delta that were selected based on the delta morphology. In this context, a total of 125 soil samples were collected from five different sampling sites, and the clay, silt and sand content of the samples were determined along with their mean weight diameter (MWD) values, aggregate stability (AS) values, amount of water retained under −33 (FC) and −1500 kPa (WP) pressure and organic matter (OM) content. Correlation analysis indicated that clay content and OM were positively correlated with MWD, and OM was positively correlated with AS. However, the sand content was found to be negatively correlated with MWD. In addition, clay, silt and OM content were positive correlated with FC and WP. Variance analysis results determined statistically significant differences between the sampling sites with respect to all of the evaluated properties. The active delta section of the study area was characterized by high sand content, while the lower delta plain was characterized by high OM and AS values, and the upper delta plain was characterized by high MWD values, high FC and WP moisture content levels and high clay and silt content. In conclusion, it was demonstrated that the examined properties were significantly affected by the different morphological positions and usages of these different areas. These results may help with the management of agricultural lands in the Batumi delta, which has never been studied before.


2004 ◽  
Vol 13 (2) ◽  
pp. 195 ◽  
Author(s):  
R. García-Corona ◽  
E. Benito ◽  
E. de Blas ◽  
M. E. Varela

Two forest soils rich in organic matter but differing in texture (sandy loam and silty loam) were heated under controlled laboratory conditions in order to examine the consequences of the heating effect that accompanies the passage of a fire on the physical properties of soil. Three samples of both soils were heated for 30 min in a muffle furnace at temperatures of 25, 170, 220, 380 and 460°C. At each temperature, the following parameters were determined: dry aggregate size distribution, water aggregate stability, total porosity, pore size distribution, water repellency and hydraulic conductivity. Heating the soils at 170 and 220°C caused no significant changes in aggregate size distribution or total porosity but increased water aggregate stability and the volume of pores 0.2–30 μm. Also, increased water repellency and strongly decreased the hydraulic conductivity. All parameters underwent much more dramatic changes at 380 and 460°C that can be ascribed to the combustion of organic matter. At such temperatures, water repellency was destroyed and the low hydraulic conductivity can be attributed to the aggregate breakdown observed under dry and wet conditions.


Sign in / Sign up

Export Citation Format

Share Document