Pasture legume roots: the key to achieving a significant reduction in the P-fertiliser costs of temperate pastures

Dr Richard Simpson, CSIRO Australia, will give this seminar titled 'Pasture legume roots: the key to achieving a significant reduction in the P-fertiliser costs of temperate pastures' at the James Hutton Institute in Dundee. This seminar will also be broadcast live to the Aberdeen site.

Abstract

Phosphorus (P) fertiliser applications are mandatory for high pasture production in southern Australia where soils are P-deficient and have a moderate to high P-sorption (fixation) capacity. However, the cost of P is increasing at approximately twice the rate of inflation and there is growing interest in whether pastures that require less P fertiliser can be developed to reduce input costs. We have assessed the “critical” P requirements (that is, the soil available-P level needed for 90% maximum growth rate) of a number of alternative pasture legumes seeking legumes that are highly productive when grown with low available-P concentrations in the soil. There were a number of species that fitted this specification and we have subsequently shown that differences in root morphology explain the differences in critical P requirements. This delineates a clear but challenging path for improving the P-efficiency of the key legumes used in temperate pastures.

Biography

Richard Simpson is a research agronomist with CSIRO’s Agriculture Flagship, an initiative that brings together research in agricultural productivity and environment sustainability. He leads a national research team assessing the feasibility of developing pastures that are highly productive but with lower phosphorus fertiliser costs. Simpson’s personal research has spanned a broad area of pasture systems agronomy including issues of pasture management, botanical composition, feeding value for livestock, plant nutrition and fertiliser use. He has provided agronomic support for the development of computer-based decision support tools for Australia’s grazing industries and has compiled a P-fertiliser calculation tool used by graziers across southern Australia. Most recently, his research has been focussed on soil biology and root damage, management of phosphorus, and land capability in grazing systems.

This seminar will be hosted by Dr Tim George, Ecological Sciences.