There are a number of articles on this in the literature - several published over the years in Soil Use and Management. Links attached.

Regards

Andrew

Article A review of visual soil evaluation techniques for soil structure

Article Application of visual soil examination and evaluation techni...

Article Visual soil evaluation in relation to measured soil physical...

Article A simple procedure for assessing soil structural, rooting an...

Dear Oswaldo, The analysis of farmer level demonstration not restricted to academics can include the soil aggregation stability test. When soil clods are immersed under water the cohesiveness of the soil will vary according to the organic matter content. This can give dramatic demonstration of qualitative difference from management practices which increase soil organic matter. Another dramatic demonstration is in the percolation rate. The draining of water through a profile and the capture of the water for its quality is also quite impacting. 

There are a number of articles on this in the literature - several published over the years in Soil Use and Management. Links attached.

Regards

Andrew

Article A review of visual soil evaluation techniques for soil structure

Article Application of visual soil examination and evaluation techni...

Article Visual soil evaluation in relation to measured soil physical...

Article A simple procedure for assessing soil structural, rooting an...

As a generalisation, intensive cultivation is easier to sustain on light textured soils because there is little structure in the first place.  However the down side is their permeability and potential for off-site environmental effects

For a 'farmer-friendly' tool to assess structural quality under grassland download the 'grassland soils guide' at:

https://dairy.ahdb.org.uk/technical-information/grassland-management/healthy-grassland-soils/#.WC6qgNKyrug

Funded by AHDB UK and developed by a team including ADAS, Chris Duller, Newcastle University and SRUC.

Other tools include Visual Soil Assessment (VSA - developed by Graham Shepherd et al. in New Zealand) and the Visual Evaluation of Soil Structure (VESS; developed by Bruce Ball, Rachel Guimarães, Lars Munkholm and Tom Batey). VESS formed the basis for 'Healthy Grassland Soils'. Other soil visual evaluation tools are available!

Thank you Mr. Paul Reed Hepperly , Mr. Andrew Butler , Mr. Paul Milham and Mr. Paul Newell Price  for the contributions

The rate at which soil clods disperse in water also gives fair idea about the structural quality  as well  as stability .

Something like clay dispersible in water...

http://www.old.international-agrophysics.org/artykuly/international_agrophysics/IntAgr_2008_22_4_319.pdf

I was also going to mention the VSA method developed by Graham Shepherd at Landcare Research, which you can view here - http://www.landcareresearch.co.nz/publications/books/visual-soil-assessment-field-guide/download-field-guide. 

I was in New Zealand when Graham was rolling it out to the wider public, and had a day in the field testing it out.  It's not difficult to carry out the assessment, and comparisons that were made between expert assessors and non-expert farmers in the development stage showed a pretty good correlation.

I feel structural soil  quality viable for farmers stands valid until the farmer hernesses the quality production on a sustained basis ...thats the only viability criterion , besides economic returns..

Dear Oswaldo,

Farmers can assess quality of soil structure in their fields by some simple ways as summarized below:

(1) Quick Feel Test: Dig a small pit (40cm x 40cm x 50cm deep), lift out a section of soil and examine it. Good soil structure consists of well-formed aggregates, which are easily broken down between the fingers when moist. Vertical fissures lead roots downwards and the soil is structurally stable. Poor soil structure has hard, sharp edged aggregates that are more difficult to break apart with horizontal “pans” restricting root growth and development.

(2) Visual Soil Assessment: Dig a 20 cm cube of topsoil with a spade. If the topsoil is less than 20 cm deep, take off the subsoil before moving to the next step. Drop your sample a maximum of three times from a height of 1 m (waist height) into the plastic basin. Lay the soil out in the large plastic bag, grading the pieces so that the coarsest clods are at one end and the finest aggregates at the other end. This provides a measure of aggregate size and distribution. Structure quality is rated in the following way.  hard and platy aggregates difficult to break: poor structure; somewhat blocky aggregates: medium structure; crumby and loose aggregates: good structure.  [Reference: www.fwi.co.uk/academy/lesson/soils-1-structure]

(3) Beside this, I suggest you to go through the following article for some more techniques for visual field assessment of soil structural quality:

Moncada MP, Gabriels D, Lobo D, Rey JC, and Cornelis WM (2014) Visual field assessment of soil structural quality in tropical soils. Soil & Tillage Res. 139:8-18

I think by now  many of our learned colleagues have given good number of field and visual observation based measures of soil quality/health measurement techniques.I appreciate all of them.