Rome: Food and Agriculture Organization of the United Nations, 2008. — 108 pp. — (FAO Fertilizer and Plant Nutrition Bulletin 18).
ISBN 978-92-5-105929-6.The efficient use of phosphorus (P) is essential to many agricultural and environmental issues. These include maintaining or improving the P fertility of soils by the judicious use of P fertilizers and other sources of P, such as organic manures including animal manures, composts and biosolids. There is also the need to conserve the finite global P resource. This bulletin reviews, analyses and synthesizes information on the efficient use of soil and fertilizer P. It presents information on the plant availability of soil and fertilizer P, with an emphasis on soil plant interactions. The focus is on the changing concepts of the behaviour of both soil and fertilizer P and on the need to define and assess their recovery and, thus, P-use efficiency more appropriately. The bulletin also outlines strategies for improving P-use efficiency. Strategies for improving the efficiency of use of soil and fertilizer P include: (i) modifying surface soil properties; (ii) managing surface soil; (iii) managing P sources; and (iv) optimizing P use through economically appropriate rates and timing. The main conclusion of this bulletin is that the efficiency of fertilizer P use is often high when evaluated over an adequate time scale using the balance method.C o n t e n t s.
Acknowledgements.
List of acronyms and abbreviations.
Executive summary.
Introduction.
Rationale for the report.
Background.
Plant availability of soil and fertilizer phosphorus.
Soil–plant interactions.
Concentration of phosphorus in the soil solution.
Movement of phosphorus to roots.
Plant root systems and phosphorus uptake by roots.
Phosphorus uptake, root systems and soil conditions.
Changing concepts of the behaviour of soil and fertilizer phosphorus and reconciling these with agronomic information.
Work in the nineteenth century.
Work in the early part of the twentieth century.
From 1950 to 1980: a period of change.
A major change in direction.
An overall assessment.
Reconciling current concepts with agronomic information.
Measuring the recovery of soil and fertilizer phosphorus and defining phosphorus-use efficiency.
Introduction.
Assessing the recovery of added phosphorus from crop yields.
Efficiency determined in relation to yield per kilogram of phosphorus applied or taken up by the crop.
Summary of methods for estimating the recovery of phosphorus fertilizers.
Soil analysis.
Using omission plots to assess the need for phosphorus.
Summary.
Improving the efficiency of soil and fertilizer phosphorus use in agriculture.
Modifying surface soil properties.
Managing surface soil and its phosphorus content.
Managing phosphorus sources
Investment to optimize soil phosphorus status and availability.
Conclusions.
References.
Annex. Case studies.
