scholarly journals Soil aggregation under different management systems

2012 ◽  
Vol 36 (6) ◽  
pp. 1868-1877 ◽  
Author(s):  
Cibele Mascioli Rebello Portella ◽  
Maria de Fátima Guimarães ◽  
Christian Feller ◽  
Inês Cristina de Batista Fonseca ◽  
João Tavares Filho

Considering that the soil aggregation reflects the interaction of chemical, physical and biological soil factors, the aim of this study was evaluate alterations in aggregation, in an Oxisol under no-tillage (NT) and conventional tillage (CT), since over 20 years, using as reference a native forest soil in natural state. After analysis of the soil profile (cultural profile) in areas under forest management, samples were collected from the layers 0-5, 5-10, 10-20 and 20-40 cm, with six repetitions. These samples were analyzed for the aggregate stability index (ASI), mean weighted diameter (MWD), mean geometric diameter (MGD) in the classes > 8, 8-4, 4-2, 2-1, 1-0.5, 0.5-0.25, and < 0.25 mm, and for physical properties (soil texture, water dispersible clay (WDC), flocculation index (FI) and bulk density (Bd)) and chemical properties (total organic carbon - COT, total nitrogen - N, exchangeable calcium - Ca2+, and pH). The results indicated that more intense soil preparation (M < NT < PC) resulted in a decrease in soil stability, confirmed by all stability indicators analyzed: MWD, MGD, ASI, aggregate class distribution, WDC and FI, indicating the validity of these indicators in aggregation analyses of the studied soil.

2014 ◽  
Vol 38 (4) ◽  
pp. 1337-1349 ◽  
Author(s):  
Jane Kelly Silva Araujo ◽  
Mateus Rosas Ribeiro ◽  
Marcelo Metri Corrêa ◽  
Izabel Cristina de Luna Galindo ◽  
Valdomiro Severino de Souza Júnior

The Garanhuns Plateau in the Agreste region of the State of Pernambuco, Brazil is characterized by humid climatic conditions due to orographic rains, unlike the surrounding semiarid region. These soils are subjected to intense agricultural use and are extremely important for the regional economy. This study was carried out in the municipality of Brejão in the Agreste region with the aim of assessing changes in humic Haplustox soils subjected to different land uses. Four plots with different vegetation covers (native forest, secondary shrubby vegetation (capoeira), traditional cropping system, and planted pasture) were selected, and samples were taken from a soil profile and four small pits surrounding it at each site. Physical and chemical properties were assessed, including aggregate stability, humic organic fractions, and a microbiological evaluation through determination of basal respiration, microbial biomass carbon, and metabolic quotient. The soils under study showed physical and chemical properties typical of a Haplustox, such as low nutrient content, low cation exchange capacity, and high levels of acidity and Al saturation. The total organic carbon (TOC) contents were high regardless of the type of land use. Aggregates < 2 mm were dominant in all the conditions under study. The TOC content was higher in the soil under capoeira, 43.91 g kg-1 on the surface, while 34.36 and 33.43 g kg-1 of TOC were observed in the first layer of forest and pasture soils, respectively. While the microbial biomass C (MBC) was greater than 700 mg kg-1 in the forest and pasture areas (in the 0-5 cm layer), and 588 mg kg-1 in the soil under capoeira, these numbers were not statistically different. In the cultivated soil area, there was a reduction of around 28 % in TOC and MBC contents. Agricultural activity contributed to degradation of the humic horizon, as can be seen from a significant decrease in the TOC and changes in the relative distribution of the humic fractions. In contrast, aggregate stability was not altered as a function of the different land uses; the soil under planted pasture and capoeira were similar to the soil under native forest. Humin was the most important humified fraction for C reserves, contributing over 40 % of the TOC in these soils.


Author(s):  
O.S. Bezuglova ◽  

Rostov Region belongs to the highly protected natural territories characterized by the continuous plowing. There territories are the only reserves with the soils preserved in their natural state. However, these areas often lack detailed information about the soils quality and composition. Surveying soils on these territories is crucial for determination of their basic physical and chemical properties. The resulted compilation of soil maps could lay a foundation for creating the Red Book of Soils and the formation of a section in the soil-geographical database of the Russian Federation. Subsequently, such information can be used as a background data for the main types of soils in the region. It will be also valuable during monitoring and justification of conservation measures.


2021 ◽  
Vol 8 (01) ◽  
Author(s):  
PEPAKAYALA VARALAKSHMI ◽  
POLAGANI NAGARJUNA ◽  
MOHAN BABU Y. N. ◽  
ADI LAKSHMI G. ◽  
ARADHNA KUMARI ◽  
...  

A study was conducted in an ongoing experiment under AICRP on micronutrients at nursery jhilli of RPCAU, research farm. The experiment consisted of thirteen treatments, of which twelve combinations were of four doses of zinc (Zn) (2.5, 5.0, 7.5 and 10 kg ha-1), three frequencies (only once, alternate year and every year) of application along with control with the no-zinc application. Rice and wheat crops were grown in succession with the recommended dosages of fertiliser viz. 120:60:40 of N: P2O5: K2O applied as Urea, DAP, and Potash, respectively. Surface soil samples (0-15 cm) were collected after the harvest of the wheat crop in the year 2018, i.e. after completion of six years of the experiment, and analysed for soil physical and chemical properties. The availability of nitrogen, sulphur, organic carbon content and aggregate stability increased, and the bulk density, phosphorous availability decreased with increasing doses and zinc application rates. No effect on soil availability of potassium, pH and EC. The treatment T7 i.e., application of zinc @ 7.5 kg Zn ha-1 in alternate year application was the best treatment with regards to yield of rice-wheat cropping (982.9 q ha-1) and also for good physical and chemical properties of the soil.


2012 ◽  
Vol 36 (4) ◽  
pp. 1299-1310 ◽  
Author(s):  
Carolina Tirloni ◽  
Antonio Carlos Tadeu Vitorino ◽  
Anderson Cristian Bergamin ◽  
Luiz Carlos Ferreira de Souza

Crop-livestock integration represents an interesting alternative of soil management, especially in regions where the maintenance of cover crops in no-tillage systems is difficult. The objective of this study was to evaluate soil physical and chemical properties, based on the hypothesis that a well-managed crop-livestock integration system improves the soil quality and stabilizes the system. The experiment was set up in a completely randomized design, with five replications. The treatments were arranged in a 6 x 4 factorial design, to assess five crop rotation systems in crop-livestock integration, and native forest as reference of soil undisturbed by agriculture, in four layers (0.0-0.05; 0.05-0.10; 0.10-0.15 and 0.15-0.20 m). The crop rotation systems in crop-livestock integration promoted changes in soil physical and chemical properties and the effects of the different systems were mainly detected in the surface layer. The crops in integrated crop-livestock systems allowed the maintenance of soil carbon at levels equal to those of the native forest, proving the efficiency of these systems in terms of soil conservation. The systems influenced the environmental stability positively; the soil quality indicator mineral-associated organic matter was best related to aggregate stability.


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%.


1974 ◽  
Vol 14 (70) ◽  
pp. 694 ◽  
Author(s):  
EH Mikhail ◽  
WI Walbran

Lemnos loam, a red-brown earth used for fruit production in the Goulburn Valley, Victoria, has degrees of friability in the subsoil as assessed in the field. Forty-one samples from three subsoil depths were obtained from 25 sites near Kyabram. Aggregate stability, as measured in the laboratory was found to be related to field assessments of friability. Exchangeable cations, pH, silt, clay and clay minerals were determined on the samples. By relating some of these measurements to aggregate stability it has been shown that exchangeable Ca++ contributes to a strongly aggregated soil (friable) ; and silt, exchangeable Na+ and exchangeable Mg++ to a weakly aggregated soil (less friable). The effect of silt and exchangeable Na+ is greater than that of exchangeable Ca++ and exchangeable Mg++. A multiple regression equation describing the effect of these four significant factors on stability percentage is presented. This equation accounts for 85.5 per cent of the variation in stability percentage. There is a strong relationship between field assessment of friability and exchangeable Ca++/Mg++ ratio; the higher the ratio, the more friable is the soil.


2007 ◽  
Vol 64 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Antonio Carlos de Azevedo ◽  
Darrel Gene Schulze

The behavior of a soil regarding the dispersion and aggregation of its particles is very important for the development of environmental and agricultural soil functions. This study was conducted to determine how aggregate distribution and stability are impacted by land uses and how the release of Water Dispersible Clay (WDC) relates to disaggregation in Oxisols from subtropical Brazil. Samples from two Oxisols, collected at three depths from sites under no-tillage (NT), conventional tillage (CT) and native vegetation (NV) land uses were shaken in 250 mL plastic bottles for intervals up to 27 hours. The mass of aggregates was measured in five size classes ranging from 53 to 2000 µm. Most aggregates larger than 500 mm disappeared during the first 7.5 hours of shaking, concurrent with an increase in WDC release and without change in soil suspension pH and electrical conductivity, without increase in smaller aggregates. Therefore, there is no aggregate hierarchy in these soils and the release of WDC was caused by breaking aggregates within the 500 to 2000 mm range. Land uses affect mass of aggregates in each size class, but the aggregate stability depends on its size, not land use.


2019 ◽  
Vol 19 (2) ◽  
Author(s):  
Marcio Gonçalves da Rosa ◽  
Antonio Domingos Brescovit ◽  
Carolina Riviera Duarte Maluche Baretta ◽  
Júlio Cesar Pires Santos ◽  
Luís Carlos Iuñes de Oliveira Filho ◽  
...  

Abstract: The ability of spiders to spread over contiguous areas (Arachnida: Araneae) is directly related to soil management conditions. The objective of this work was to study the effect of land use system (LUS) on the abundance and diversity of soil spider families and their relationship with soil physical and chemical properties. The evaluated LUS were: native forest, eucalyptus reforestation, pasture, crop-livestock integration, and no-tillage crop. Samples were collected in three municipalities of Southern Plateau of Santa Catarina, considered as true replicates, during winter and summer. A total of 270 samples was taken in each area and season. The sampling points were arranged in a grid of 3 × 3 m, spaced by 30 m. We evaluated soil physical, chemical, and microbiological attributes and the abundance and diversity of spider families, collected by soil monolith and soil traps. A total of 448 spiders were captured, 152 in winter and 296 in summer, distributed in 24 families and 52 species/morphospecies. There was a seasonality effect related to the land use systems and the highest Shannon-Wiener diversity index was recorded in the native forest in both sampling periods. Most families of spiders have a direct dependence on soil physical and chemical properties, such as microporosity, exchangeable aluminum, calcium, magnesium, and potassium during the winter. Organic matter, nitrogen, pH in water, weighted average diameter, soil density, and microbial biomass carbon exhibited dependence during the summer. Vegetation type and soil management are the factors that seem to affect most the occurrence of spiders. The families Theridiidae and Nemesiidae are dependent on sites with low human intervention.


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