Phosphorus fertilization recommendation


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A more trustworthy P recommendation by implementing the intensity, buffering capacity, quantity concept into agricultural practice.

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Phosphorus fertilization recommendation

  1. 1. A more trustworthy P recommendation by implementing the intensity, buffering capacity, quantity concept into agricultural practice A r j a n R e i j n e v e ld
  2. 2. Introduction
  3. 3. Introduction (back then) ● P fertilization recommendations for agricultural crops are based on soil tests from ~ 1900 onwards ● Already at that time, it was suggested that two or more soil P test would give more insight in soil processes and improve recommendations ● However, mostly for reason of costs, this was not implemented
  4. 4. Introduction (nowadays) ●Modern soil analysis methods (costs decreased) ●Optimal crop yield and quality increasingly important (world food) ●Environmental protection has become a topic ●P resources are exhaustible ●Legislative restrictions for P-fertilization ●Farmers value soil P tests, doubt the current recommendations, and are interested in improved allotment of P
  5. 5. So, there seems room for a more trustworthy P recommendation 5
  6. 6. Material & Methods
  7. 7. Material Literature: Throughout 20th century combination of soil tests was promoted ● P intensity= plant available P ● P buffering capacity = capacity to replenish plant available P when P is taken up by crops ● P quantity = total capacity for P replenishment
  8. 8. 8 Direct Available Nutrients Plant Available ElementsSoil Stock Total Soil Stock Methods P-total or P-oxalate P-Al or P-CAL or P-Olsen P-CaCl2 P-water Metaphor Basement Kitchen Table Plate Kg P ha-1 3400 545 4.7 2.5 Soil Quantity Soil Intensity
  9. 9. Method Stepwise introduction i) Scientific research to further test the concept ii) From 2004 onwards on all reports (all farmers) P intensity P-CaCl2 P capacity P-Al/P-CaCl2 P quantity P-Al iii) Validation in field experiments (grass, maize, potatoes) iv) Making it an ‘official’ recommendation (>2010)
  10. 10. Results
  11. 11. Results: variation of P intensity within a P quantity category 0 1 2 3 4 5 6 7 8 9 10 11 12 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50 50 - 60 60 -70 70 - 80 >80 0,71 1,07 1,4 2,3 3,3 4,12 5,2 7,85 8,56 P intensity, P-CaCl2 mg P kg-1 Pquantity;P-AlmgP2O5100g-1 percentile, 10 - 50% percentile, 50 - 90%
  12. 12. Results (P recommendation) ● On average: lower P recommendations (15 kg P2O5 ha-1) ● Different allotment over fields ● In general: lower recommendations when soil P status is low, but small recommendation even when soil P status is higher
  13. 13. Discussion
  14. 14. Discussion: improvements Buffering capacity is represented by ratio P-Al/P-CaCl2 Recommendations could be improved by measuring Fe, Al, and Ca on routine basis (to establish Fe-P, Al-P, and Ca-P binding) Risk of leaching can be established
  15. 15. Discussion: international (P-Olsen) A lot of variation in plant available P within P-Al, but also within P-Olsen, and P-CAL
  16. 16. Discussion: other nutrients Concept can also be used for other nutrients: For example: K plant available (K-CaCl2) K soil stock (K-CEC)
  17. 17. Soil P status of a soil is established by one soil P test Government in the Netherlands has the intention the use quantity and intensity characteristics to classify soils and establish P applications from 2015 onwards. Discussion: legislation
  18. 18. Conclusion
  19. 19. Conclusion Improved allotment of P useful for food, farmer and environment 19
  20. 20. Thank you all! Questions? Arjan Reijneveld Gerard Abbink Martijn van Oostrum Debby v. Rotterdam Wim Bussink