After 10-growth-year alfalfa furrowed

experimentation that include 9 kinds of alfalfa-grain rotation patterns has been carried out in dried area of southern Ningxia during 2003-2005 year.It has been studied that effects of different rotation patterns on third spring wheat yields

soil nutrients

pH values and enzyme activities.The results showed that there are significant differences at above indexes of the third year rotation spring wheat of 9 kinds of alfalfa-grain rotation patterns

organic matter

total N

available N

available K average contents and pH values of 0-60 cm soil layers all decreased

which breadths is 0.05~2.24 g/kg

0.019~0.325 g/kg

0.118~12.280 mg/kg

8.87~166.88 mg/kg and 0.03~0.31

respectively.It has cumulation effect that No.1 and No.2 year rotation grains absorb soil water and nutrients

which decrease by rotation year adds.It is dominating that rotation crops consume soil nutrient at the first rotation year and consumption quantity was different with crop species.When the first rotation crop is spring wheat

consumption of this rotation pattern's soil N and P is the least of all

it is second when it is millet

and it is the most when it is potato.As millet favor to available K

soil available K was use greatly when former stubble grains was millet

it is more little than millet when former stubble grains was potato

and it is the least when spring wheat.Soil organic matter and available P decrease greatly when those three grains rotate with free arrange in groups.In all rotation patterns

potato and millet use greatly soil water than spring wheat

so it lead to soil keep high alkalescence degree.In the alfalfa-grain rotation patterns

grain succession pattern induce to soil urease activity decline

which breath is more great than other patterns'.Potato succession pattern lead to soil Alkaline Phosphatase activity fall

soil Invertase activity of crop succession pattern is more high than others.