Maize (Zea mays L.) and wheat (Triticum aestivum L.) are two
main crops in China, whereas P, either in a sole chemical P or a combination
of chemical P plus manure P, is often applied to increase their
productivity. Under six 15-year long-term (1991–2005) fertilizations
(three no-P, two chemical P, and one chemical P plus manure P) at
three contrasting alkaline soils withmaize–wheat rotations in northern
China, the objectives of this study are to address differences in (1) soil
Olsen P accumulation patterns, (2) responses of soil Olsen P to APB
and (3) relationships between change in soil Olsen P and organic C
accumulation.