Through gradual regression analysis to ten kinds nutritions of soils of 54 counties

Saanxi province

the optimum regression modelfor soil utritions(including alkaline--N

quick action Ps quicick ackac-tion K

B and Zn) has been set up

It shows that soil fertility is thelimit factor of wheat production in Guanzhong plain

but this is not ase in North Shaanxi loess plateau gully hill region

Finally，correlation analysis and fuzzy cluster on soil nutriments have been done

From above mentioned

we can get a lot of information about wheat production

soil assessment and nutrition diagnosis