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Feature Soil Conditioning and Improvement of Fertilizer Application by Soil Diagnosis

Analysis of soil chemical properties in soil diagnosis
-Introduction of simplified field soil testing tools –
Daisei GOTO*

This is an extract from “Soil Conditioning and Ecological Farming, June–July 2011”, which is the periodical publication from “Japan Soil Association”. With the approval from association, we translated into English an article, written by Daisei GOTO, Agricultural Science Equipment Division of our company.
We wish to express our gratitude to Japan Soil Association for the special consideration to us.
Fujihira Industry Co., Ltd.


To make plants grow healthy, the soil needs to stay healthy to grow it. Soil diagnosis, in other words, soil health examination, is indispensable to be familiar with soil condition, to improve and maintain the optimum condition for crop production.
In soil diagnosis, general evaluation is made on the basis of analysis of each properties described in table 1.
Especially, chemical properties diagnosis is highly important to make a fertilization plan. This plan is designed on the basis of data from soil chemical properties analysis (further described as soil analysis).

In soil analysis, standard method is not determined, but there are methods of detailed analysis (routine procedure or conventional method). The extraction or measurement methods are different depends on target nutrient, crop, soil character and target region.
This is because, the purpose of soil analysis is to measure morphologically available nutrient for crop, not the total volume of nutrient.

Process of soil analysis consists of preparatory operation to extract the target nutrient from soil and measuring operation of nutrient concentration in the extracted solution (Figure 1). As the detailed analysis requires much time and labor, simplified and rapid testing method is used on sites of soil analysis.
Here I would like to mention different types of soil analysis, tools for on-site soil analysis and its recent trend.

2.Detailed analysis and simplified analysis

As mentioned above, there is no standard method in soil analysis. Usually in research and experimental institutions, detailed analysis (routine procedure,conventional method) is adopted. It is possible to get the accurate result by these method, but it requires long time for preparatory operation, and it is necessary to be a good command of precision analytical equipment,
which needs sophisticated operation technique. (Table 2).
On the other hand, in the soil diagnosis organizations (such as JA), it is necessary to rapidly deliver the results to producers to reflect it in appropriate cultivation management. For this purpose, generally soil analysis with labor and time-saving method is executed. (Table 2.)
Meantime, Zen-noh type Soil Analyzer ZA-II and Soil Plant General Analyzer SFP-3, which are utilized in many of the soil diagnostic organizations, are distributed together with necessary tools and reagent in complete set. And, to obtain the closer result to detailed analysis, these equipment are worked out with built-in compensation formula of extraction ratio. There are installed the formula to figure out the nutrient concentration, too, for direct reading. By using these systemized exclusive analyzer, it is possible to simply and rapidly to make soil analysis.(Photo1.)
Photo1. Soil Plant General Analyzer SFP-3 

3. Simplified testing method

Til now, soil analysis in research institutes
and diagnostic organizations were introduced.
On the other hand, at the outside field with no
laboratory equipment, it is possible to roughly
grasp the soil nutrient condition, using
simplified testing tools or analytical kit, such
as Dr.Soil.
There are various features of Dr.Soil
(Photo2, 3) such as 1. Sample raw soil can be
collected in volume, without scaling. 2.
Extraction for 9 elements, excluding pH, can
be done at once. It is not necessary to extract
one element by one element. 3. Exclusive
extraction and filtering tools are included for simple and rapid operation. 4. Any electronic equipment is not required. Evaluation is made by comparison with colorimetric or turbidimetric chart.  

What is more, as the extraction method is different from detailed analysis, the extraction rate differs in some element.
By compensation of values on colorimetric or turbidimeric chart, closer result to detailed analysis can be get.
An example of testing procedure and testable parameters are shown in Table 3 and Figure 2.
Meantime, by using Nodai-method simplified soil diagnostic kit “Midorikun”, it is possible to check the soil nutrient condition very easily, for the limited 4 parameters of pH, NO3-N, Water soluble P, water soluble K.(Photo. 4)
 Photo 2. New Soil Nutrient Tester Dr.Soil
 Photo 3. Soil analysis, using Dr.Soil
(Photo provided from Japan Bio Farm)
Photo 4. Nodai-method simplified soil diagnostic kit “Midorikun”

1. Take 0.5ml of extracted solution to test tube  
4. Recent trend

These years, fertilizer management on the basis of soil diagnosis is increasing in its importance, and analyzed sample number is increasing, too. The fertilizer cost gets higher attention from producers due to its steep rise in price, and the necessity grows to prevent the decrease of harvest and deterioration of quality due to unusual weather. For the purpose to intensively manage the plenty samples of soil analysis, soil diagnostic organizations started to install automatic preparation system and automatic analyzer.
Our equipment, High Speed Soil Nutrient Automatic Analyzer “SNA-24i” and Full Automatic General Extraction and Filter Unit “CEC-10” are adopted in soil diagnostic organizations throughout Japan, and contribute to smoothly manage the soil diagnosis.
In the end, I would like to mention our research and development. For more than 20years after starting of its sales, Dr.Soil has been practically used in Japan as well as in overseas countries. Now, we proceed the development to renew it, to include CEC, which shows durability of applied fertilizer, and P-abc, which shows volume of phosphate fixation, as the possible target of on-site soil analysis.
And, SFP-4i (tentative model name, successor of SFP-3) is under development, with another one year target for starting of sales.
2. Add stilled water up to the increment of 3.  
3. Add 0.5ml of reagent No. 2 (NH4-N testing reagent A) and stir. 
4. Add 0.5ml of reagent No. 3 (NH4-N testing reagent B) and stir. 
 5. Compare with NH4-N colorimetric chart and read the value after 10minutes.
Photo 5. High Speed Soil Nutrient Automatic Analyzer “SNA-24i”
 Figure 2. Procedure of NH4-N testing operation
For inquiries about this article, please send an e-mail to : overseas@fujihira.co.jp,
International Sales Section of Fujihira Industry Co., Ltd,