Abstract: By using 3-year field experimental results and related meteorological observation data, the dynamic characteristics of leaf area index (LAI) and the allocation characters of ecological resources for different yielding spring maiz e (Zea Mays L.) population in Huadian of Jilin Province were studied. The resul ts showed that the dynamic characteristics of relative LAI, with the relative gr owth days of test population, relative effective accumulated temperature, relat ive sunshine hours and relative rainfall as independent variables, fitted r ational formula y=(a+bx)/(1+cx+dx2), and the regression equation of maize yiel d with the ratios of growth days before and after silking (x1), effective accu mulated temperature before and after silking (x2), rainfall before and after s ilking (x3), and sunshine hours before and after silking (x4) was y=546519 +1781064x1-2323614x2+409341x3+628737x4 (R2=08187，P<001) , with the effects of these ecological factors on yield being in the sequence of x1>x2>x3>x4 according to the absolute values of partial regression coef ficients. In super high yielding (1549986 kg·hm-2) spring maize populat ion, the allocation ratios of x1, x2, x3, and x4 were 143, 141, 14 4, and 140, respectively. Therefore, in Northeast China, appropriate early sow ing of spring maize to prolong its growth days with more rainfall and sunshine h ours before silking could attain high yielding, and high or super high yield cou ld be achieved when the allocation ratios of x1, x2, x3, and x4 were all about 14.

Key words: urease, microbial biomass, organic matter., chernozem