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Determining the longer term decline in plant‐available soil phosphorus from short‐term measured values
Author(s) -
Johnston A. E.,
Poulton P. R.,
White R. P.,
Macdonald A. J.
Publication year - 2016
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/sum.12253
Subject(s) - eutrophication , environmental science , phosphorus , fertilizer , soil water , term (time) , grassland , agronomy , nutrient , ecology , soil science , biology , chemistry , physics , organic chemistry , quantum mechanics
Once phosphorus (P) applications stop, it is important to know how long it will take for plant‐available P in soil to decline to a particular level for soils with a history of intensive management. The rate of decline in the absence of applied P can be expressed as a half‐life, that is the time in years for it to halve relative to the lowest level measured in the soil. This knowledge is essential when planning long‐term policies for managing the P status of soils. It is important to farmers who wish to optimize applications of P fertilizers and make better use of accumulated P residues to ensure that plant‐available P does not fall below the critical level for the soil and crop because of the risk of losing yield and the inefficient use of other inputs, especially N fertilizer. Lower levels of plant‐available P are also desirable for environmental and ecological reasons. Allowing plant‐available P to decline to the critical level from unnecessarily high concentrations will reduce the risk from P on eroded soil causing adverse effects of eutrophication in surface water. Low levels of plant‐available P are usually considered necessary for establishing species‐rich grassland. A method for determining the longer term decline in plant‐available soil P from short‐term measured values is presented.