The Impact Of Different Pine + Eucalyptus Mixed Models For Soil Physical And Chemical Properties

This study on the basis of the PaiYangShan Forest Farm experimental planting,selecting typical three kinds of Masson Pine and Eucalyptus mixed model,and comparing with at the same time,create pure forest,to clarify the Masson Pine and Eucalyptus nitrogen fixation of forest tree growth effect and the influence of soil physical and chemical properties,which will provide a scientific basis for the continued operation of artificial forests,the results of the study to guide the practice of Masson Pine + Eucalyptus management has important guiding significance.(1)The average chest diameter and average tree height were found in 3.5a and 4.5 a,and the pattern a(see table 2-1,FIG.2-1,and below)was the maximum,and the Masson Pine pure forest was the minimum,and the difference was significant.However,in the comparison of the growth rate of the thoracic diameter,SC(Masson Pine forest)was the maximum of 1cm,and the mode C was the minimum value of 0.57cm;And there are significant differences.3.5a and 4.5a raw Eucalyptus average size of chest diameter and chest diameter,mode B was the first,but the mean diameter of the four afforestation modes was not significant(P>0.05).3.5 a and 4.5 a,average tree height of Eucalyptus,model C for maximum,CK(Eucalyptus pure forest)as the minimum value,no significant difference between three kinds of mixed mode(P>0.05),but in three kinds of mixed mode and pure forest widely exist significant difference;In the comparison of the growth rate of trees,mode B is optimal.(2)The mixed model of Masson Pine and Eucalyptus has a significant improvement on the physical properties of soil.Relative to the eucalyptus pure forest,three kinds of mixed mode are reduced soil bulk density,improve the capillary porosity and capillary porosity,total porosity,soil field capacity,capillary water holding capacity,maximum water holding capacity.The soil layer of woodland becomes loose,increasing the soil ventilation,which is beneficial to the growth of tree roots.The soil physical quality of eucalyptus was optimal.(3)Different afforestation patterns have significant influence on soil N elements,P elements and K elements(P<0.05).In the soil of 0?20cm,the contents of N elements,P elements and K elements of the three mixed modes are higher than that of two types of pure forest,and the content of mode B is the maximum,which is the optimal value.In the trace elements,the Cu content and Zn in the pattern A and B soil are generally higher than the two kinds of pure forest,and the difference is significant.Five afforestation modes,the soil is acidic,and the afforestation model has significant influence on soil pH value;In 0?20cm,the soil pH value of model B is the largest and the optimal value,and the soil pH value of AC is the lowest,which is the lowest value.In soil below 20cm,pure forest soil has a high pH value.The soil organic matter content of the mixed mode afforestation was higher than that in the pure forest,and the soil organic matter content of mode B was the highest in the soil of 0?40cm.(4)The soil physical properties are closely related to chemical properties.Soil bulk density and PH value,organic matter,total K,hydrolytic nitrogen,quick effect P,quick effect K,effective Cu are all significant negative correlation.The maximum water content is positively correlated with PH value and total K,and is positively correlated with organic matter,hydrolyzed nitrogen,quick effect P,quick effect K and effective Cu.There is a significant positive correlation between the water content of the capillary and the speed effect K,which is positively correla.ted with the hydrolyzed nitrogen and the quick effect P.The amount of water in the field is significantly correlated with the quick effect P,the quick effect K and the effective Cu.The capillary porosity is positively correlated with the quick effect K.There is a significant positive correlation between non-capillary porosity and quick effect P and effective Cu.The total porosity is positively correlated with organic matter;The hole degree is positively correlated with the hydrolytic nitrogen,quick effect P,quick effect K,and effective Cu.(5)Comprehensive evaluation method by applying the method of fuzzy membership function on soil physical indexes and soil chemical properties index evaluation and sorting,respectively,and then will be accumulate,belonging to the two aspects of value averaging,it is concluded that comprehensive evaluation score.The final evaluation score is:mode B>mode C>SC>mode A>AC,optimal mixed mode is mode B.