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Impact of soil use on aggregate stability and its relationship with soil organic carbon at two different altitudes in the Colombian Andes. Agronomía Colombianavol. Therefore, it is necessary to know the relationship between aggregate stability and the content of SOM in different types of soil use at two different altitudes of the Colombian Andes.
This study examined the conditions of soil aggregate stability expressed as a distribution of the size classes of stable aggregates SA and of the mean weighted diameter what is diagonal relationship class 11 the stable aggregates MWD. 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 what is diagonal relationship class 11 plots: tropical rainforest, an association of oil palm and pastures, and irrigated rice.
Soils were sampled at three depths:and cm. The physical properties, mineral particle size distribution, and bulk density were measured. The SA with size 1. The SA nutrition courses in germany size 0. The SA with size between 0. Key words: soil degradation, soil structure, organic matter, agriculture.
Por lo tanto, es necesario conocer la relación entre la estabilidad de agregados y el contenido de MOS en diferentes tipos de uso del suelo a diferentes altitudes en Los Andes de Colombia. Se muestreo el suelo a tres profundidades: 0 what is diagonal relationship class 11 5, 5 a 10, y 10 a 20 cm. Se midieron las propiedades físicas, distribución por tamaño de la partícula mineral y densidad aparente.
Los AE de what is the meaning of no correlation 1. Los AE de tamaño 0. Los AE de tamaño entre 0. The Norte de Santander province is located in the northeastern area of Colombia, on the eastern ramification of the Andes range. This province is characterized by strong altitudinal variations approximately from 50 to m a.
The variations in landscape configuration and changes in the vegetation modify its tropical weather IGAC, a. Food production is one of the most important socioeconomic activities in this region. For this reason, it is essential to acknowledge that the soil use is adapted to each particular biophysical condition in terms of the altitude. The zones of the region with cold and warm climate represent the areas with the most intense agricultural land use.
This fact has generated soil degradation problems, such as compaction or erosion IGAC, a what is diagonal relationship class 11, which may be related to the soil's physical properties, in particular, to its structure and its aggregates stability Pla, Soil aggregates are the product of a complex physical-chemical and biological aggregation process, in which various factors such as climate, soil use, plants, and soil properties interact Bronick and Lal, Among the soil properties that determine directly the aggregation and its stability, the texture, total organic carbon, microbiological activity, soil fauna and inorganic cementing agents exchangeable Ca and oxyhydroxides stand out Six et al.
According to Oadesmacroaggregation is controlled by management in soils where organic matter is the major binding agent. The best distribution of organic materials and mix with inorganic colloids occur through the root systems, particularly the fine, bushy and extensive root systems of grasses. However, in intensively disturbed soil or with lack of root growth, the opposite effect may be observed. Changes in soil use, from natural forest to agricultural use, frequently generate modifications what is diagonal relationship class 11 the soil organic carbon content.
This affects the aggregates and soil stability directly, which leads to soil what is meant by random variable loss Sena et al. According to Lozano et al. This generates limitations, such as surface seal or compaction, that alter the normal soil hydrological functioning and generate erosion. The problems of aggregate stability in soils have been associated with changes in the organic carbon of soil, caused by changes in the soil use Nascente et al.
Aggregation is a hierarchical process, in which the union of mineral components of the soil with organic components occurs at a microscopic scale. In this process, humified organic carbon participates to form micro aggregates, and then, at a larger scale, the particulate organic carbon or light organic carbon takes part in the formation of macro aggregates and mega aggregates.
Therefore, the increment in organic carbon increases the dynamic of aggregation and in turn, the greater aggregation favors the preservation of soil organic carbon Six et al. Consequently, there has been a growing interest in identifying the soil use systems that best suit the stability of soil aggregates from the preservation of soil organic carbon. In this sense, this study aimed to examine the effect of three soil use systems at two altitudes of the Andes mountain range, located in the Norte de Santander province of Colombia.
The analyzed soils were located in two municipalities of the province of Norte de Santander in the northeast of Colombia. The first one was a Humic Dystrudepts soil in the high mountain area with a cold climate, located in the Vereda Monteadentro, at the municipality of Pamplona. Three adjacent lots on this soil were selected, each one with different soil use and cover: natural forest, kikuyo pastures, and intensive horticultural crops. All lots were located within the premontane wet forest zone, with an average annual temperature of The other soil was a Fluvaquentic Dystrudepts in the low area of alluvial valley with a warm climate, located in the Vereda Astilleros, at the municipality of El Zulia.
Three adjacent lots were selected by the following soil uses and covers: natural forest, oil palm with pasture and intensive rice cultivation with irrigation. The study was conducted with an experimental arrangement of a 2x2x3 factorial design with three replicates, with the climate, soil use and soil depth as factors. In each selected plot, undisturbed soil samples were collected in metallic cylinders and disturbed composite samples were also taken.
Soil samples were collected at three depths: 0 to 5 what are compositional techniques in art, 5 to 10 cm and 10 to 20 cm. The study was focused on the arable layer or soil tillage what is diagonal relationship class 11 0 to 20 cmwhich is separated into three layers: the first 5 cm is considered the place where the largest amount of particulate organic matter would accumulate; the layer from 10 to 20 cm is the depth where the largest amount of stable or humified organic matter would be present, while the medium layer could be considered as a transition layer.
A systematic sampling strategy was performed on a diagonal transect line of m with three equidistant sampling points 10 m from the edge and 40 m between them. In what does the nasty mean what is diagonal relationship class 11 point, why internet is not working properly today soil subsamples were collected for each depth to integrate the composite sample of that point.
Those sub-samples were collected on a cross traced over each sampling point, where the distance between the crosses was 1 meter. The undisturbed samples were extracted in metallic cylinders of 5 cm of diameter and 5 cm of height, taken in threefold at each depth in each sampling point. The soil aggregate stability was determined by the modified Yoder's wet sieving method proposed by Pla Stability tests were performed on aggregates with diameter from 2. The wet sieving was carried out for 10 min with an array of sieves corresponding to 2.
This allowed making the proper correction when calculating the size distribution of stable aggregates retained on each sieve. Also, the aggregates smaller than 0. The mean weighted diameter MWD was calculated as an important stability index, from the percentage of the total weight of the aggregate fraction retained in each sieve Wi and the average diameter of the fraction for each sieve Xi. To calculate the MWD, expressed in mm, Equation 1 was used:.
The disturbed soil samples also what is diagonal relationship class 11 the measurement of mineral particles contents sand, clay, and silt by the modified Bouyoucos method IGAC, band, meaning of market by philip kotler know the organization of soil constituents, the structural arrangement description was performed according to the guidelines for soil description FAO, The oxidizable total organic carbon TOC was determined by the digestion and wet acid oxidation method of Walkley and Black with colorimetric measurement by spectrophotometry IGAC, b.
Measurement of organic carbon in the particulate fraction of soil organic matter POC and the organic carbon of the humified fraction of soil organic matter HOC was performed by physical fractioning of the soil organic matter SOMby the method of suspension and agitation in water with sieving, using sieves with openings of 2. They were transformed to a weight expression in megagrams Mg of organic carbon OC ha -1for which the soil bulk density Bd and the thickness of the soil layer were considered; the first expressed in Mg m -3 and the second expressed in cm, through Equation The soil bulk density Bd was determined by the modified method of the metallic cylinder of Uhland Pla, The results were analyzed concerning the compliance of the normality statistic assumptions and the variance homogeneity, by the Shapiro-Wilk and Kolmorogov tests.
The Pearson correlation coefficients were determined and the dispersion graphics between the related variables with the structural stability and the SOC content were made to interpret their behavior and the ratio of the stability of aggregates with the SOC in their different pools. Data of the what is diagonal relationship class 11 particle content in the Humic Dystrudepts soil evaluated in the lots at cold climate presented clay in a proportion of Sand predominates at all depths from 0 to 20 cm and in all the soil use systems turns in coarse and medium coarse class textures.
Considering the Bd of the evaluated soil in the cold climate Tab. This fact is normal in soils of medium texture class, and low in soils of coarse texture class. This represents a favorable condition, which means the existence of a good relationship between the volume occupied by the solids and the pores in this soil Pla, TABLE 1 Principal statistics for the data of the examined variables in the soils under cold and warm climates three soil depths, three soil uses, and three replicates.
The Fluvaquentic Dystrudepts soil that was evaluated in the warm climate expressed contrasting data of sand, silt and clay content compared to the other studied soil. Clay is in proportions from The Bd of the soil in the warm climate Tab. This represents a high value in soils with fine and medium-class textures, indicating an unfavorable condition that could result in structural problems by compaction in the soil Pla, The contrasts in the contents of sand and clay in both soils are important because the SOC amount can be influenced by the distribution of these particles Mujuru et al.
In addition, the SOC has an important effect on the soil particle aggregation, with a correlation between the content and kind of SOC and the size and aggregates stability Martinez et al. Therefore, it is what is diagonal relationship class 11 to be aware of the particle distribution in the studied soils. The results of aggregates stability in real life example of relational database cold climate soil Tab.
The SA from 0. These data reveal a favorable condition of structural stability, considering that the In the case of the aggregate what is diagonal relationship class 11 in the warm climate soil Tab. This high proportion of micro aggregates is clear evidence of the unfavorable physical conditions in this soil. Table 2 shows that the structural stability measured by the SA proportions of size classes presents a response with significant statistical effect due to the climate in 4 of the 5 size classes of SA.
The class without significant effect in SA is between 0. It is deduced that this effect matches the condition of higher SOC content in soils of cold climate. It can be observed that there was a significant effect only over the size class of SA from 0. The other four classes remained without significant effect.
This corresponds with the statement that micro-aggregation is not so sensitive to management. Therefore, it is more difficult to improve micro-aggregation through normal farming practices Oades, In the case of depth, there is no significant effect in any of the size classes of SA. The lack of effect over the SA due to the depth of the soil is understood by the fact that the three depths belong to the horizon A of each soil.
Therefore, there are no relevant differences in factors involved in the stability of aggregates, such as texture, mineralogy and structural arrangement type, grade, and class of aggregates between the three layers of each soil Tabs. Hence, none of the three evaluated use systems affects significantly this good condition.
For the MWD, the soil in cold climate has the biggest structural stability Fig. The crop presents MWD values in the layers of 0 to 5 and 5 to 10 cm, of 1. For the deepest layer 10 to 20 cmthe MWD of the crop 2.