Raindrops hit bare soil with enough force to break the soil aggregates. Water then accumulates on the surface and increases runoff which takes soil with it. Besides, hill slopes are prone to erosion. The amount of hill slope erosion largely depends on how the land is used. However water or wind moving over the surface will also remove more soil, and contribute to erosion. Light soils are more prone to erosion.

Very good response Dr Malhotra. I think, soil organic carbon is really most pivotal soil qualify parameter having strong cascading effect on soil tilth..Please

thanks Fathima,Anoop kumar and suresh for your answers

so from this I can make a decision that I have to do mechanical analysis of soil samples

Hi Ashish

Excellent points made by Fatima.

Your question mentions hilly areas in a watershed. So, in that scale, maybe removal of so called top soil (a loss), deposited in another area which has its positive benefits in some cases (such as deposition of fertile soil, nutrients and organic matter).

A physical factor in areas prone to erosion, that is good to consider for soil quality assessment is Soil Depth, particularly the top soil horizon, or the depth to a restricting layer.

Good luck.

The risk of water erosion is related inter alia to the type of soil, and its compaction, the particle-size distribution, the stability of soil aggregates and the organic components content. Generally, it is believed that the most susceptible to erosion and surface runoff are silty soils (especially loess soils) and sandy soils. According to some researchers, the general view of the greatest susceptibility to erosion of loess soils is not true. They think that the most susceptible to water erosion are soils developed from sand. E.g. according to Sharma et al. (1991), the most susceptible to erosion are sandy, then loamy, and finally clay materials.

Sincerely

Pawel Wisniewski

Some of the soil properties that you must look for to evaluate the propensity of a soil to erosive forces are:

Soil Structure: Stable soil structures are required to ease water infiltration. When water infiltrates easily, this reduces overland flow which would otherwise wash the topsoil. Soils that have stable structures have higher mean weight diameter (MWD), aggregated silt+clay (ASC), clay flocculation index (CFI) and less of dispersion ratio (DR) and clay dispersion index (CDI).

Soil organic Matter (SOM): Organic matter contributes in binding soil aggregates in order to form stable structure. Any soil that has low SOM is likely to be easily eroded.

On a slope, the severity of erosion is influenced by the type of slope, whether it is a concave or convex slope (bulging slope). Erosion is pronounced on convex slopes because of the shape of the slope, which give very little time for any water to infiltrate, thereby increasing soil detachability.

The length of slope also another important factor; the greater the slope length, the greater the erosion menace.

thanks, Utibe Edet Utin , Paweł Wiśniewski ,

as you have added my confidence ,at some corner this i am not able to express, so again thank you very much.,

soil samples which I have collected should be tested for its structure(mechanical analysis)and organic contents

Dear Ashish Guruji

I propose an analysis of particle size distribution, organic matter content, pH, calcium carbonate and macronutrients (P, K, Mg).

Regards

Pawel Wisniewski

Any soil areas that do not support adequate vegetation will obviously are prone to erosion. Vegetation will improve more root volume,OC and better aggregates that would prevent erosion.

if we are talking about general principle I think Flocculation need to be considered. This happnes in relation of the dominance of mono-valent element such as Na. Flocculation is the process by which individual particles of clay aggregate into clotlike masses or precipitate into small lumps so the soil have very poor/weak structure and thus vulnerable to erosion .

How do these principles differ in degraded versus non-degraded soils..

More than 50-60 parameters can be used for soil quality (SQ) assessment. They are basically divided in to physical, chemical and biological. Some of these parameters are measured in laboratory on disturbed and undisturbed samples (such as pH, CEC, Texture, etc.), and some are evaluated in the field or site (such as soil depth, slope, etc). Selection of appropriate parameters for SQ assessment, first depends on the objective (in this case soil erosion).

Many parameters have been suggested here by our colleagues for soil erosion susceptibility. I believe, a good assessment should include at least 1 parameter from each category (physical, chemical and biological). In addition to laboratory analysis (texture etc), for soil erosion susceptibility, really field parameters MUST be considered as well! They could be soil depth, slope, vegetative cover, etc. Otherwise, assessment and recommendations based only on laboratory analysis of texture and some chemical parameters, will be weak and may not work in actual field situation, especially for soil erosion that occurs constantly in the nature.

Also, the suggested parameters here, add up to a large number of parameters, making it exhaustive and expensive for the researcher. An important part of soil quality assessment, is determining what is called Minimum Data Set. It has its own methods and can be different in different environments and objectives. These refs maybe useful.

https://hrsl.ba.ars.usda.gov/cesium/LiYong.pdf

http://www.swcs.org/en/publications/soil_quality_and_soil_erosion/

http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/aesa8692

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwi6qqna7LfXAhVfFMAKHRisCvgQFggkMAA&url=http%3A%2F%2Fwww.scielo.cl%2Fpdf%2Fjsspn%2Fv14n4%2Faop7714.pdf&usg=AOvVaw37Y5lQxiftFGurGxf09XBW

Non-construction soil is more prone to erosion, This can be cured by adding organic matter, Cultivation of windbreakers and try to reduce surface runoff

Any soil with poor aggregation quality would be more prone to soil erosion. This could be the result of intensive tillage impact, massive loss of SOM and so on.

Sandy soils having poor adhesive capacity are most susceptible.