Changes of Soil Nutrients in Different Aged Torreya grandis ‘Merrillii’ Stand

During October and November 2019, 49 sample plots were established in Torreya grandis ‘Merrillii’ stands with age of 15-99-year, 100-299-year, 300-499-year, 500-999-year and ≥1 000-year in main production area, namely Zhuji, Shaoxing, Shengzhou, Dongyang and Pan’an of Zhejiang province. Determinations on soil nutrients showed that the content of soil hydrolytic N decreased gradually with the increase of tree age, and the content of soil available P, available K and organic matter increased first and then decreased, with the highest content in the 100-299-year stand. The soil pH value fluctuated with the increase of tree age, and showed an overall increasing trend. The content of Ca in soil decreased firstly and then increased with the increase of tree age, while the content of Mg had no evident change with tree age. The contents of soil available nutrient, organic matter and Ca decreased with the depth of soil layer, while the content of Mg was opposite. Variance analysis showed that tree age had significant effects on content of soil available nutrients, organic matter, Ca, Mg content and pH and soil layer had significant effects on soil available nutrients and organic matter content, but had no significant effects on pH, Ca and Mg content. The correlation analysis among soil nutrients demonstrated that soil organic matter content had extremely significant positive relation with available N (P<0.01), and evident positive relation with available P and available K (P<0.05). Soil available K content had extremely significant positive relation with available P (P<0.01). Soil pH had extremely significant positive relation with Ca (P<0.01), but negative with hydrolytic N, available P and available K, and it had no obvious positive relation with organic matter (P>0.05).