Aluminum is the most abundant metal that makes up 7% of the earth's crust and occurs in a number of different forms in the soil.It is harmless as oxides and aluminosilicates.Nevertheless

if the soil pH <5 or even 5.5

as is now the case on 40% of the arable lands in the world

Al will be solubilised into toxic forms

generally referred to Al~(3 )

which is a primary factor limiting plant growth have been attributed to several physiological pathways.A possible alternative to ameliorate Al toxicity is the application of such organic manure as rice straw.Laboratory incubation studies were conducted to determine the dynamics effects of rice straw on different Al forms

the results strongly revealed that Al forms and soil pH changed rapidly in 30 days.Soil pH increased rapidly in the first 10 days

and then decreased to the 30th days and tends to the balance.As we all know exchangeable Al are negatively correlates with pH

so exchangeable Al decreased in the first 10 days with the pH increasing

and then increased to the balance.Adsorbent hydroxyl Al had complex hydrolisis and the polyreaction after straw application and changed a little.Exchangeable Al and adsorbent hydroxyl Al transform to organically complexed Al after straw application

so the curve of organically complexed Al increased to the peak on the 10th day

and then decreased to the balance.Because the time of incubation study is short

soil organic matter will not aggregate

so organically complexed Al is instable

which will be change with the environment changes

so the capacity of alleviating Al toxicity is weak.