Hanna Instruments HI 3896 - Manual (Page 4)

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The physical structure of the soil depends on the dimension of the particles of its make up
(Tab. 1). In addition, the particles also differ based on their shape and volumic mass (mass
per unit of volume)
DIAMETER OF THE PARTICLES (mm) CLASSIFICATION
> 2 stony texture
2 - 0.2 coarse sand
0.2 - 0.02 fine sand
0.02 - 0.002 silt
< 0.002 clay
Soil is divided into many classes of texture, according to the percentage of the basic
particles (clay, sand and silt). If, for example, we have a soil with 37% clay, 38% sand
and 25% silt, the soil is classified as “clay loam” (Fig. 2).
PHYSICAL STRUCTURE
Tab. 1. Particles
classification according to
“International Society of
Soil Science” (ISSS)
Fig. 2. Types of soil in
relation to the texture
Among different types of soil, the loam soil is considered as being suitable for crop
growth. However, other types of soil, with a rational management, can also provide
positive results.
The soil texture is the cause of important aspects such as porosity, tenacity, adhesivity
and plasticity.
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Apple very low 150 120 230
low 130 90 150
medium 110 70 120
medium-high 90 50 90
high 80 40 60
very high 70 20 40
Grape very low 150 90 230
low 120 70 180
medium 100 60 150
medium-high 90 40 120
high 80 30 90
very high 70 20 60
Peach very low 200 120 230
low 160 90 150
medium 140 70 120
medium-high 120 50 90
high 100 40 60
very high 80 20 40
Pear very low 150 120 230
low 130 90 150
medium 110 70 120
medium-high 90 50 90
high 80 40 60
very high 70 20 40
The soil analysis is very useful, in order to plan fertilization and to know the residues of
fertilizers in relation to the crop, tillage and climate. An analysis can highlight shortages
and help the understanding of the causes of an abnormal growth.
Testing the soil during the crop cycle and comparing the results with the plant growth can
be an useful experiment for the next cultivation.
1) Extracting Soil Sample
– With a large field, take 1 or 2 samples per 1000 m2 (0.25 acre) of homogeneous
areas.
– Even for smaller areas, 2 samples are recommended (the more the samples, the
better the end-results, because the sample is more representative)
– For a small garden or plot, 1 sample is sufficient
2) Avoid extracting samples from soil presenting obvious anomalies
3) Sample quantity:
Take the same quantity of soil for each sample. For example, use bags with similar
dimensions (1 bag per sample)
CROP SOIL CONTENT ADVISED DOSES (kg/ha)
N P
2
O
5
K
2
O
Tab. 7.
SOIL ANALYSIS
Sampling
(data ESAV)