[USCC] P accumulation in manured fields

[frank]

Rufus,

First I wonder what type of P test should be done on compost to measure 
the 'problem' phosphorus?
I suggest 'Dissolved acid-hydrolyzable phosphorus'. But first we should 
know if when using this method adding Al to the compost will reduce the 
measured P -as we need it to do if we use Al to solve the problem. 

SM 4500 Method: filter a water extract (suggest 1:5 w/w) thru 45um pore 
membrane filter / add dilute acid and boil for 90 min.

Frank








(snip)

>High P accumulation in soil is already regulated in some states. Imperfectly regulated. Composts are not yet strongly regulated in relation to plant available or water soluble P in the amended soil, but regs are moving toward limiting the Water Extractable Phosphate (WEP) of the soil amendment or amended soil. Slopes and other factors which affect runoff and erosion are increasing included in planned regulations for manure P applications.
>  
>

>(snip)
>
>Most evidence shows that the P is adsorbed on Fe and Al hydroxides, although some is slowly converted to inorganic compounds of P in the soil or diffuses inside the micropores in the oxides. Plants can utilize the adsorbed and organic P, and even the P compounds, by the mechanisms they use within the rhizosphere to dissolve and absorb soil P for normal soils. We did one test of the P available to wheat from soils on my long term biosolids plots at Beltsvsille and found that with no P fertilizer the wheat obtained adequate P for full growth. So the P adsorbed on Fe and Al has remained plant available. Other's research also supports this conclusion.
>  
>

>Regards,
>
>Rufus Chaney
>Beltsville, MD
>
>
>-----------------------------------------------------------------------
>Jerry d'Aquin, Con-Sul, Inc.   
>     One area which is of concern to me on a multi-decade time horizon is the practice of applying alum to fields receiving high doses of poultry litter. This approach has been promoted by the U of Arkansas as a means to convert soluble P in litter to an insoluble form. This permits high-volume litter applications while limiting P runoff and percolation into surface  and ground waters. In my mind, we are (at best) over-accumulating ground P until the point when it again becomes an issue (if it ever ceased being so) AND artificially injecting Al as aluminum phosphate into a long  term equation -- rather than simply "biting the bullet" and  dispersing litter over a larger area and at doses appropriate for requisite  nutrient uptake of those crops. Am I wrong regarding the use of alum?
>
>_______________________________________________
>Compost maillist  -  Compost at composter.com
>http://mailman.cloudnet.com/mailman/listinfo/compost
>
>This list is a service provided by the US Composting Council.
>
>_______________________________________________
>
>
>Ongoing Sponsors of the USCC Discussion list are:
>
>Food Industry Environmental Network (FIEN), a regulatory and policy e-mail alert service for environmental, food and agricultural industry professionals.
>Contact Jack Cooper 301/384-8287 JLC at fien.com --- www.fien.com
>
>Renewable Carbon Management, LLC with the containerized, in-vessel NaturTech Composting System www.composter.com rcm at composter.com
>
>(c) Copyright 2006 United States  - All rights reserved
>
>Members posting CC copies to the list and other addresses will have their posting privelages suspended.  No exceptions!
>
>Opinions expressed represent only the poster and are not necessarily the opinion or policy of any organization.
>
>Non-members of USCC are encouraged to join the Council through our website at: http://www.compostingcouncil.org/membership.cfm     For discussion list policies and information regarding subscribing, unsubscribing, digest or other options, go to:http://mailman.cloudnet.com/mailman/listinfo/compost
>
>For additional help in unsubscribing or to report bugs and problems, send a message to the List Manager, Jim McNelly, at compost-owner at composter.com 
>
>
>
>  
>

-- 
Frank Shields
Soil Control Lab
42 Hangar way
Watsonville, CA  95076
(831) 724-5422 tel
(831) 724-3188 fax
frank at compostlab.com
www.compostlab.com