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8. We recommend to develop suitable and robust techniques to assess the amount of soil P which would become available to trees through desorption processes in the medium to long term. For this purpose, P desorption isotherms (sequential extraction procedures) using anion based extractants on a representative set of samples (from the BZE collective) are suggested. This part of method development would require intensive research efforts. 9. In order to apply the above method to all the BZE samples, two alternatives are available: (a) To develop suitable pedo-transfer functions to assess P desorption parameters. This may require additional analysis of the soil samples causing additional cost and the need for substantial financial resources. (b) To use near infrared spectroscopy methods to develop suitable predictive models for determining parameters of P desorption isotherms. We recommend the latter because of its simplicity, low cost, and versatility, which makes it an appropriate and usefulness technique for a very large sample collective (grid samples from nationwide forest soil inventory study). 4
EXECUTIVE SUMMARY 1. The first nationwide forest soil survey, BZE1, included an assessment of tree nutrition on 1014 sites. For the assessment, concentrations of nutrients in the foliage and total amounts in the litter layer and soil samples were determined. In the report by BMELF (1997), it was noted that a significant number of forest sites had low to very low P levels in the foliage. The percent of sites for the different tree species which had low to very low P concentrations in the foliage were (in brackets are the critical limits used) : Norway spruce (Picea abies) – 59 % (
Page 1 and 2: ASSESSMENT OF CHANGES IN THE PHOSPH
Page 3: RECOMMENDATIONS 1. The results of t
Page 7 and 8: High N inputs and uptake by plants
Page 9 and 10: 12. It is recommended that a series
Page 11 and 12: Below, these hypotheses are being d
Page 13 and 14: Douglas fir which suffered from abs
Page 15 and 16: easons of such results. Another rea
Page 17 and 18: The frequency and the amount of mas
Page 19 and 20: usually present in the leaves. In v
Page 21 and 22: level class are given in brackets.
Page 23 and 24: 2.3 Factors influencing the foliage
Page 25 and 26: example the compiled data from BZE-
Page 27 and 28: mostly during periods of active gro
Page 29 and 30: Table 3: Number of cases included f
Page 31 and 32: P % 0.1 0.2 0.3 0.4 Kiefer 4 4,5 5
Page 33 and 34: P % 0.1 0.2 0.3 0.4 0.5 Eiche 4 4,5
Page 35 and 36: 19.84 n=144 NVHU< 1228 | CMENGE< 38
Page 37 and 38: 2.6 Changes in P concentrations in
Page 39 and 40: in section 1 of this report. In sum
Page 41 and 42: Fig 8: Mixed linear model describin
Page 43 and 44: Fig 10: . Mixed linear model descri
Page 45 and 46: Table 6: Concentration of P (mg/g)
Page 47 and 48: (Nilsen and Abrahmsen 2003) reporte
Page 49 and 50: 3. PHOSPHRUS IN FOREST SOILS 3.1 In
Page 51 and 52: sequential extraction scheme of ext
Page 53 and 54: Table 8 : Sequential extraction pro
Page 55 and 56:
phosphates at pH values
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3.2.2 Inorganic forms of P - desorp
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Mineralisation of organic P does no
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enhances the dissolution of Ca-phos
Page 63 and 64:
water, and sodium bicarbonate metho
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Table 10. Estimated transfers and c
Page 67 and 68:
3.3 Use of pedo-transfer functions
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the amount taken up at each site. T
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is commonly saturated with HCO3 is
Page 73 and 74:
assess P status or any changes in P
Page 75 and 76:
Forest Ecol. Manage. 92, 119-152. B
Page 77 and 78:
Rev. Plant Physiol.Plant Mol. Biol.
Page 79 and 80:
and N-free-fertilisation. Plant Soi
Page 81 and 82:
Sparling GP, Hart PBS, August JA. (
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