Effect of nitrogen load on growth and photosynthesis of seedlings of the hybrid larch F1 (Larix gmelinii var. japonica × L. kaempferi) grown on serpentine soil

Abstract

We studied the growth and photosynthesis of the hybrid larch F1 (Larix gmelinii var. japonica×L. kaempferi) grown on serpentine soil and the effects of soil N load, to determine the performance of this species as reforestation material in serpentine regions. We prepared 16 experimental plots (2m×4m each), eight on serpentine and eight on brown forest soil, and planted one-year-old cutting seedlings of the hybrid larch F1 in each plot, in May 2007. Ammonium sulfate was supplied to half of the plots of each soil type in 2008 and 2009, at a load of 47kgNha−1year−1. Although the growth and photosynthetic capacity of hybrid larch F1 seedlings in the serpentine soil were limited, the rate of growth in serpentine soil was greater than that of Sakhalin spruce (Picea glehnii) that is dominant species in serpentine regions. There was significant interaction between soil type and N load for the growth and photosynthetic parameters. The N load adversely affected growth and photosynthetic parameters in the serpentine soil, while improved them in brown forest soil. Although the growth rate of hybrid larch F1 without N loading showed high potential as an afforestation species in serpentine region, increasing deposition of N might be a threat to the growth and photosynthesis of the hybrid larch F1 in serpentine soil.