Kindly see this link and get desired information http://nebeginningfarmers.org/farmers/land/land-environment-facilities-tutorial/know-your-soils/soil-nutrients/

Hi Govind.. I guess the link mentioned is wrong.  

Dear Mr. Teixeira,

The following publications could help you:

1 - Acín-Carrera et al. (Impacts of land-use intensity on soil organic carbon content, soil structure and water-holding capacity - Soil Use and Management, Volume 29, Issue 4, pages 547–556, 2013);

2 - Li & Shao (Change of soil physical properties under long-term natural vegetation restoration in the Loess Plateau of China - JOURNAL OF ARID ENVIRONMENTS Volume: 64, Issue: 1, pages: 77-96, 2006);

3- Price et al. (Variation of surficial soil hydraulic properties across land uses in the southern Blue Ridge Mountains, North Carolina, USA - JOURNAL OF HYDROLOGY Volume: 383, Issue: 3-4, Pages: 256-268, 2010);

4- Liu et al. (The effects of conservation tillage practices on the soil water-holding capacity of a non-irrigated apple orchard in the Loess Plateau, China - Soil and Tillage Research, Volume 130, June 2013, Pages 7-12);

5- Mahe et al. ( The impact of land use change on soil water holding capacity and river flow modelling in the Nakambe River, Burkina-Faso - Journal of Hydrology, Volume 300, Issues 1–4, 10 January 2005, Pages 33-43);

6- Buchanan et al. (Influence of texture in bauxite residues on void ratio, water holding characteristics, and penetration resistance - Geoderma, Volume 158, Issues 3–4, 15 September 2010, Pages 421-426);

With Regards.

Hi Luiz, 

thank you very much for your attention.  But I guess my question was not so clear.  What Im looking for is some published article where people compared from the same plot water holding capacity measured from disturbed and undisturbed soil samples.  A very methodological question ...some friends told me that these kind of articles were published  many years ago ...  

Dear Mr. Teixeira,

I am sending you two links which may be interesting to you:

1. http://onlinelibrary.wiley.com/doi/10.1111/ejss.12058/abstract

The first paper uses the CPV method to identify the water pressure of field capacity which is considered constant for a soil under various compaction conditions while what is changing is the water content at field capacity. The method can be used even to distrubed soils.

2. http://link.springer.com/article/10.1007%2Fs11242-011-9876-9

In the second paper is a primitive analysis of CPV method

I hope it will help you

There are several methods for estimating water holding capacity as evident by several scientists:

1. Harding, D.E. and Ross, D.J. 1964. Some factors in low-temperature storage influencing the mineralisable nitrogen of soils. Journal of the Science of Food and Agriculture15: 829 – 834.

Details: 

Water holding capacity (WHC) is the amount of water retained by the soil after it has been saturated and allowed to drain overnight. Soil biochemical tests are routinely carried out at a target soil water content equivalent to a certain percentage (usually 60%) of the sample’s WHC, as results can be affected by very wet or dry conditions.

Water holding capacity is determined by keeping fresh soil overnight with water at a 1:2 ratio in a filter funnel plugged with glass wool and stoppered. The stopper is then removed and the soil allowed to drain for 3 hours. The water content of the saturated soil is then determined using method 104(ii). The procedure is as described by Harding and Ross (1964).

Other suitable method I will suggest in due course of time

Hi People, thank you for trying help me. But my question is a very specific one: The same soil sample was measured by its holding water capacity at different potentials by using different methods (Disturbed and Undisturbed samples) ? Does it delivery the same results ?

Do you kknow an article abou that ?

Anyway: Thanks for rewievinng the concepts of water holdign capacity to us.

All the best

I don't know if this comparison between water holding capacity measured from disturbed and undisturbed samples has never been done. The problem is that the definition of the water holding capacity (the answer above) does not suit to any laboratory measurement. Only the physical modelling of the drainage of a soil profile from saturation could give an answer corresponding to the definition (see Braudeau et al. 2009).  However several laboratory methods or standard calculations can be chosen depending on the understanding we have of the soil water and soil structure interaction (see Braudeau et al. 2005 using the shrinkage curve and Braudeau et al. 2014 using the water retention curve and standard defiition).

Article Hydrostructural characteristics of two African tropical soils

Hi Wenceslau,

Actually, I do not know if there is any work about the comparison between disturbed and undisturbed samples. The measurement of the soil water holding by using disturbed samples is not common because the structure of the soil is destroyed. I have tried to evaluate soil water retention curves with disturbed samples some year ago, but I have never published these results. My idea was to analyze the effect of wetting and drying on the structure of damaged samples. Sorry.

Luiz

Hi Erik thank you for you comments and  articles. Very nice concept about "typology of the pedostructures". Thank you. The question about disturbed and undisturbed in the forum was to try to harmonize some soil data banks I want to see if we have a trend when use disturbed samples in pressure like 6, 10 kPa the trend is sub-estimate water holding capacity. Some equipments are available now (as Hyprop) and expanded range tensiometers I guess they will change the way that we do the water holding capacity and hydrological soil balances. Your concepts is very welcomed. Im also developing some combination of instruments to make feasible (costly, timely and labor demand) to measure the soil water retention points direct  in the field.

Hi Luiz thank your for your comments.

Some people believe that after some potential as 500 kPa or higher disturbed samples are better than undisturbed. It is because the errors and time consuming in the analyses of water holding capacity in the traditional cylinders (5 cm high) lead to worst results than those form disturbed samples in small rings or done with potentiometers (WP4) or centrifuges. I dont know how correct is this statements.  Im trying to learn more about it. The permanent wilting point (1500 kPa) is traditionally done with disturbed samples (at least the soil moisture equipments is built to that) however I have some colleagues that do not agree and are still asking to have this measurements done in the cylinders (it take ages to "equilibrate") in the Richard Chamber. 

One more reference link regarding water holding capacity determination,

yours sincerely

file:///C:/Users/hcl/Downloads/JeradDLId0393vol007issue001.pdf

Hi Wenceslau,

Based on my experience for sandy soils it is possible to use disturbed samples for matric potentials above -500 kPa without any problem. For clayey soils, sometimes the difference of water retained on the structure of the soil between -500 and -1500 kPa is minimum and the errors associated to the methods of water content measurement or thermodynamic equilibrium time judgment can justify the use of disturbed samples for these potentials. Actually, the use of undisturbed samples for very negative matric potentials e.g. -1500 kPa as you said is time consuming and presents several difficulties regarding the equilibrium judgment. Another additional problem is the lack of temperature control in the laboratory, which can also affects the equilibrium of the samples for large period of times.

Dear Wenceslau,

This is an intersting question that bothers everyone that tries to generate a well defined pF-curve. The best way would of course be to equilibriate a large undisturbed sample; then you are always sure about a valid result. But our equipment is unfortunately not yet capable of performing accurate results this way, because a long equilibrium time has the great disadvantage that the apparatus/ceramics will suffer from drying via the vapour phase; there is no (hanging) water (column) from below the ceramic plate (pressure plate) left to feed the sample during equilibrium time. Supplying water from above is very tricky. Thus when the measurement takes too long, it becomes uncertain if the applied pressure is the real applied pressure. A standard rule that must be kept in mind is that larger (macro) pores  empty at lower suctions than smaller pores. As soon as they are emptied they do not contribute any more to the equilibrium result, so disturbing these pores is not a problem beyond this pressure. The macro pore volume is then been accounted for via the Theta=(mass liquid/mass solid)*dry bulk density. A sandy soil has generally no structure at all, so the pores are made of the interspace of/between the particles themselves. Disturbing such samples is not a problem , because the same pores will emerge in disturbed circumstances. The more structured a sample is, the more larger and smaller non-paricle based pores exist, and thus the more important it is to measure an undisturbed sample. Therefore the expert must value the disadvantages of long equilibrium times against the disadvantages of disturbing the sample, keeping the 'amount of structure' in mind. I'm still longing for better equipment, so we don't have to bother any more.

Hi Wenceslau,

Very good queston.

25 years ago I was very interested by this question and developed some models water flow in different types of soils based on Richards equation but with some specific options. One of this model was designated for structural soil (composed with macroaggregates) having two pore spaces for water flow between and in macroaggregates. To estimate separately hydraulic properties of these pore spaces I developed special additive model based on Arya approach and in this case linking size of textural and structural elements/ Thus was quite useful to model preferential flow and was (in this time) published in Russian journals and not in English. Some years ago I renew this approach and published presented it in English at some soil scientific events like attached to this message.

Hi Wenceslau!

In our paper we investigated the temporal changes of soil physical quality under two residue management systems, in South Italy. Some references were provided in order to highlight the different type of correlation (positive or positive) between plant available water and soil bulk density. This latter may be different according to the soil texture.

https://www.researchgate.net/publication/263221607_Temporal_changes_of_soil_physical_quality_under_two_residue_management_systems

Article Temporal changes of soil physical quality under two residue ...