Many of the soil testing methods are 40-50 or more years old.Several scientists suggested modifications/improvements in those methods over the years.It seems to me that the improvements need to be monitored ,documented and even validated for inclusion in the original method.Some macro-methods have now become micro-methods. New instrumental methods are now available in place of old methods.By keeping basic principle/ concept intact whatever changes emerged over time need to be collected ,monitored,documented and validated for use by new researchers.Is some body doing this?Are there any reviews of the developments in a particular method or soil test methods in general with focus on improvements in methodology.?
The paper I attach and is available here
http://nawfert.iung.pulawy.pl/zeszyty/pelne/30%202008.pdf
may be somewhat related to the question. Here we have comparison of different methods used in Central Europe fertilization recommendations. Based on the same soil samples. It does not answer the question, but may be quite useful.
We do methodical inter comparisons in the Baltic countries. But what was a big deal 40-50 years ago, cross validating soil extraction methods seems to be outdated today. One reason is probably that the expectations in soil analytical methods never have been really fulfilled or with other words the possibilities of soil testing methods have been greatly overestimated. A big problem is that for most of the methods around the way they have been calibrated is more or less obscure and/or biased. So its a lot of believing in the methods and interpretation schemes offered by commercial laboratories.
I have conducted a correlation to test the accuracy of a 1:5 fixed volume for electrical conductivity compared to the accepted ECe by saturated paste. My purpose being to correlate the two and use the fixed volume to find the correlated electrical conductivity to allow for consistent monitoring of salinity changes on a local bird refuge. Given the criteria for creating a saturated paste is not discrete in nature, and can be subjective to the individual conducting the soil test. Monitoring over long periods of time in an arid-semiarid rich in nutrient soils that parent materials consist of those spewed from an ancient volcano and the remnants of a prehistoric lake, salinity reaching up to 60,000 micro Siemens 30 feet below the surface.
Maybe new soil testing methods have not changed because there would be difficulty comparing old logged soil test data to look for trends?
Sir
I have developed 'Om Soil Testing Kit' for analysing 19 soil parameters (chemical, physical and biological). While doing, I have collected some of the literature, standard methods for different parameters.
You have raised very right thing. Some person or group of persons should take the task and pool all the information old and new along with the source. Definitely it consumes time and the work has to be planned on project mode by taking assistance.
We should think and formulate a project and submit to ICAR.
I very well appreciate the responses of Drs.Stepien,Schnug,Olsen,and Rajakumar .Wider adoption of soil test methods across large areas especially with some uniformity in soils ,climate and crops has been done in different regions of USA or Europe with some good success.I have seen soil testing laboratory manuals containing common methods adopted for different regions of USA.Similar situation may prevail in Europe.As I understand,Dr.Stepien's remarks/comments are in the same direction. Some commonality is their in calibration and recommendations also.As pointed out by Olsen,easy to follow methods are needed and they should continue for long term for monitoring purposes. Dr.Schnug 's comment is a big question for all soil scientists especially for soil fertility specialists.On one side the demand for soil heath assessment, management and monitoring is increasing(Now there is public awareness and political will in developing countries).One the other side we have our limitations. We have conventional (rather old) soil testing methods,rapid soil tests as mentioned by Rajakumar and emerging new sensor based methods(suitable for precision agriculture) .Rapid soil tests may meet requirements under certain conditions in limited way and they may not replace the conventional methods Also the sensor based or on- the -go methods need a few decades to get established.My only concern is how best we can use the well established methods in contrasting soils in different environments.The following paper( in the review part) gives several developments in commonly used Olsen's method for available P testing.Increasing pH of the extractant,soil solution ratio,shaking time,and concentration of 0.5M NaHCO3 etc influenced the amount of P extracted.We need such reviews for all soil test methods and some basic soil properties for their appropriate use in different soil environments.The should be compiled, documented and validated.
Development of an alternative to the Olsen'test for determining corn plant-available phosphorus in calcareous soils.by M.R.Maghsoodi et al. Iran Agricultural Research(2015)34(1)92-104.
file:///:/Users/matrix/downloads/IAR.30961426883400.pdf
Sir,
Very good discussion. In calcareous soils definitely Ca will interfere with available P, henece the method has to be as you said with reference,
Most agricultural labs in the developed countries are private enterprises nowadays, which dont have the resources and the impact to pursue interlaboratory method development, calibration and evaluation of analytical methods and therefore rely on whats be done, published and commonly accepted in the past. In connection with our work on Precision Farming we have developed a concept named "on farm (or local) experimentation and calibration", where we use established methods offered by certified labs and calibrate those for a particular farm / area.
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