Effects of nitrogen loading under low and high phosphorus conditions on above- and below-ground growth of hybrid larch F1 seedlings

iForest: Biogeosciences and Forestry

Fujita, S.¹ 

关键词: Ecophysiology;    Nitrogen Deposition;    Phosphorus;    Fine Root Production;    N: P Ratio;    Hybrid Larch F1;   

DOI  :  10.3832/ifor2395-010

学科分类：社会科学、人文和艺术（综合）

来源: Societa Italiana di Selvicoltura ed Ecologia Forestale (S I S E F)

【 摘 要 】

Abstract: Under present environmental conditions, hybrid larch F1 (Larix gmelinii var. japonica × Larix kaempferi) is a promising afforestation species as it has a high growth rate and tolerance against grazing damage, disease and cold. However, the input of nitrogen (N) to forests due to the increase of anthropogenic N is causing imbalances of N compared to other nutrients, especially phosphorus (P), thus affecting the root growth of healthy seedlings. However, knowledge on how different N and P conditions affect F1 root growth is still limited. In this study, various N (3 levels) and P (no addition and addition) conditions were imposed to investigate the effect of N loading on larch F1 seedlings under different P conditions. Needle N: P ratio, aboveground growth, belowground growth as well as fine root production were measured. The results showed that needle N: P ratio was higher under low P loading, and aboveground growth of seedlings increased with N loading at both low and high P conditions. Relative fine root production was decreased by N loading. On the other hand, fine root to total dry proportion was increased by N loading at no P addition, suggesting that limited P availability could increase fine root production. Total root proportion to total dry mass was decreased by N loading at both P conditions. We concluded that N loading has different effects on above- and below-ground growth of larch F1 and its effects may also differ according to P conditions, indicating that both N and P conditions should be carefully considered when planting hybrid larch F1.

【 授权许可】

Unknown