Routine Soil Analysis

Introduction

We are specialists in soil fertility management and developing fertilizer programs for farmers.  We carry out fast and affordable soil analysis in our laboratory, and we use the results to make the right recommendations for your farm. We are independent and don't sell any farm input products and we only offer you the best advice.


Soil testing is essential for building sustainable soil fertility and fertilizer management programs for your farm, to increase your crop yields and reduce your input costs.   Accurate sampling is absolutely critical to a successful soil management plan as all recommendations are based on the samples submitted to the lab.


How to take a soil sample in a field crop


Equipment Needed

1.Sample bags(we can supply at no charge)

2.  Auger or shovel

3.  Bucket

4.  Sample submission forms (please request these from us)

5.  Field logbook

6. Labels or marker pens


Selecting Sample Areas


When you are selecting areas to sample you must remember that there is no set size but we don’t recommend single sampling areas of>20 Ha.The actual size of the sample area is determined by certain factors.Areas that differ in any of the following should be sampled separately: 

    1. Soil type.
    2. Soil colour.
    3. Previous cropping history.
    4. Previous lime or fertilizer applications.
    5. Slope.
    6. Drainage


Where very large areas of land are uniform, divide the land into areas that would be treated as a unit (i.e.one field),and sample these areas individually.

One sample should not represent more than one field,as individual fields will have had different treatments in the past.As mentioned ,it is recommended that one soil sample should not represent more than 20 hectares regardless of apparent field uniformity.This is because non-uniformity is usually difficult to assess over broad areas of landscape. Large fields can be divided for sampling purposes into two or three smaller sections. 

Make a map of your fields and always label the field with the same name – this way you can follow your field’s soil health historically.


Sampling depth

Depth of sampling is critical because tillage and nutrient mobility in the soil can influence nutrient levels in different soil zones.Sampling depth depends on the:

  1. Crop.
  2. Cultural practices.
  3. Tillage depth.
  4. Nutrients to be analyzed.


Plant roots,biological activity and nutrient levels occur mainly in the top soil (0-25 cm) hence most of the soil samples are collected within this layer.For tree crops and other deep rooted crops,samples from the sub soil (25–50 cm) should also be collected.

Sampling Procedure

Procedure

  1. One sample should consist of about 20 cores taken from the set area.It is recommended that the cores be taken from the area in a zig zag pattern as shown below:
  2. Scrape away surface litter and crop residues and sample the whole core from the true soil surface to 25 cm depth.
  3. Put the soil cores in a bucket and mix thoroughly. 
  4. Label the bag carefully with your company name,farm name,field name,sample depth and date, and crop to be grown. Fill the soil bag half full (500g), from this mixed representative sample.
  5. Different tools such as a soil sampling tube,soil auger,or spade may be used to take soil samples.Do not use galvanized,soft steel or brass equipment if trace metal analyses are desired.  Clean all tools between sampling.
  6. Avoid taking samples from areas such as lime piles, fertilizer spills, ant hills,  gate areas,livestock congregation areas,poorly drained areas,dead furrows,fertilizer bands,old fence rows,or any other unusual areas.

The quality of any analysis is directly related to how well the sample is collected.


 

 

by Shambaza team

Advertisement