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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  • 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. Introduction 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. 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. So, there seems room for a more trustworthy P recommendation 5 6. Material & Methods 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 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. 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. Results 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. 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. Discussion 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. Discussion: international (P-Olsen) A lot of variation in plant available P within P-Al, but also within P-Olsen, and P-CAL 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. 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. Conclusion 19. Conclusion Improved allotment of P useful for food, farmer and environment 19 20. Thank you all! Questions? Arjan Reijneveld Arjan.Reijneveld@blgg.nl Gerard Abbink Martijn van Oostrum Debby v. Rotterdam Debby.vanRotterdam@nmi-agro.nl Wim Bussink Wim.Bussink@nmi-agro.nl

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