High soil fertilty = high food production Establish soil fertlity with soil tests With only one soil test > 20 soil characteristics can be measured. Based on a single soil test fertilzation recommendations are given, but also additional information like a soil organic matter balance, and a water retention curve is given to farmers and their extension services.

1. Arjan Reijneveld
August 27, 2013
A grip on soil fertility
Dr. Arjan Reijneveld
The Netherlands

2. Soil fertility
Soil fertility = nutrient and water supplying
and retaining capacity of the soil
Soil fertility is, since beginning of 20th century,
established by soil tests

3. Soil tests:
until now

4. Soil tests until now
For every soil characteristic (N, S, P, K,…)
a different method
- Time consuming chemical analysis
- Expensive
- Mostly based on knowledge of the 1960th - 1970th

5. Soil tests:
nowadays

6. Soil tests: nowadays
Soil in a jar of glass
Analysed with near infra red method (NIR)
In every soil sample > 20 soil characteristics

7. > 20 soil characteristics
Among others:
N-total
S-total
P-total and P saturation
Ca-, Mg-, K-, and Na-CEC
Plant available Ca and K
Soil texture (clay, silt, sand)
pH
CEC, Total C
Soil Organic Matter (SOM)
Soil Organic Carbon (SOC)
CaCO3

8. From soil test to report
Those > 20 soil characteristics of the soil test are
transformed to a report

9. On the report
● Fertilization recommendations (nutrients)
● Among others Phosphorus
● Extra information
● CEC
● Organic matter balance
● Soil structure
● Water retention curve
● Soil type
Example II
Example III
Example IV
Example I

10. Example I
Phosphorus

11. Phoshporus (P)
Recommendations based on:
● Plant Available P
as well as on
● Soil supplying capacity
Improved root development:
better uptake of nutrients
and less drought sensitive

12. Example II
CEC

13. CEC and yield potential
13

14. CEC can be improved by:
Effective CEC improved by pH improvements
CEC improved by input organic matter
- Crop residues
- Compost
- Animal manure
- Green manuring
- Organic fertilizer

15. Example III
Organic matter

16. Soil organic matter (SOM)
2.9 % SOM
mineralisation
Input through crop residues
Shortage, to be filled in with
animal
manure, compost, green
Not only a measurement but also information about
maintaining soil organic matter content (balance)

17. 17
Improved SOM status
Improved soil workability
Less drought sensitve

18. Example IV
Water
retention
curve

19. Water retention curve
Plant available
water
Wilting point
Field capacity

20. Water retention curve
Information about:
Which fields are most drought sensitive
How much mm of water can be irrigated
Too much irrigation
● water will leach to deeper soil layers
● nutrients will leach

21. Finally

22. Sampling sites
NIR stations could be established everywhere (worldwide)

23. Higher soil fertility = higher production
With NIR technique much insight in soil fertilty
More insight can be used to optimise
- Production (yield)
- Product quality
- Water use
- Prudent use of minerals
Results of soil tests should be discussed with famers
and extension services (advisors) to fully exploit its
added value
In conclusion

24. Soil tests can contribute to
● Profitable farming
● Feeding a steadily
increasing
world population
FAO, 2012

25. Thank you
Arjan Reijneveld@Blgg.nl