TY  - CONF
ID  - orgprints9905
UR  - http://orgprints.org/9905/
A1  - Cornish, P. S.
TI  - Phosphorus Management on ?Extensive' Organic Farms with Infertile Soils


Y1  - 2007///
N2  - Two case-study farms with negative P balances maintained acceptable productivity without fertilisers, apparently by ?mining? ?available? P reserves in surface and subsoil.  The question for these organic farms is ?how long before fertiliser is needed??  With six farms on lower-fertility, weakly acidic to alkaline soils and modest rainfall (380-580 mm/yr), low productivity was related to P deficiency despite positive P balances from using allowable fertilisers. Useful supplies of compost or manure were unavailable.  Until effective allowable fertilisers or microbial inoculants have been developed, there is a case for using soluble forms of P fertiliser on soils where soil-solution P is low and soil P-sorption is high, so that additions of soluble P ?feed the soil, not the plant?.
AV  - public
KW  - phosphorus
KW  -  Australia
KW  -  soil fertility
KW  -  grain
KW  -  grazing
ER  -