两种立地条件下麻栎人工林地上部分养分的积累和分配

麻栎(Quercus acutissima)是一种分布广、用途大、耐干旱瘠薄的乔木树种, 掌握其生长规律和养分利用特性对麻栎人工林的科学经营十分必要。对安徽省滁州市红琊山林场两种立地条件下的麻栎人工林的生长和养分状况进行了对比研究, 结果表明: 在土壤含石量较高、养分含量较少的立地条件下, 12年生的麻栎人工林地上部分生物量为49 180.2 kg·hm^-2; 林木养分总累积量为633.9 kg·hm^-2, 其中N、P、K、Ca、Mg的累积量分别为119.9、18.7、88.5、368.6和38.2 kg·hm^-2。在土壤含石量较少、养分含量较高的立地条件下, 12年生麻栎人工林地上部分生物量为90 774.8 kg·hm^-2; 林木养分总累积量为993.6 kg·hm^-2, 其中N、P、K、Ca、Mg的累积量分别为203.5、23.0、146.9、553.6和66.6 kg·hm^-2。所以, 立地条件对麻栎生长和养分累积具有显著影响。较差立地条件下的麻栎对土壤养分的富集系数较大, 但其凋落物的养分含量较低。研究显示, 麻栎可以通过养分奢侈吸收、提高养分内循环、减少养分损失等途径来适应低养分环境。

Nutrient accumulation and allocation of aboveground parts in Quercus acutissima plantations under two site conditions in Anhui, China

Aims Quercus acutissima is widely distributed in China. Because of high resistance to drought and the adaptation to poor soil condition, it is commonly planted in mountainous and hilly areas for soil and water conservation and wood production. Our objective is to study its growth and nutrient use strategy for the purpose of better plantation management.Methods We analyzed biomass, nutrient contents and nutrient distributions of 12-year-old Q. acutissima stands at two different sites at Hongyashan Forest Farm, Chuzhou, Anhui, China: a poor site with high gravel content and low soil nutrient concentration and a rich site with low gravel content and high soil nutrient concentration.Important findings In the poor site, the aboveground biomass of Q. acutissima was 49 180.2 kg·hm^–2, total nutrient accumulation in the aboveground biomass was 633.9 kg·hm^–2 and the storage of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) was 119.9, 18.7, 88.5, 368.6 and 38.2 kg·hm^–2, respectively. In the rich site, the aboveground biomass was 90 774.8 kg·hm^–2, total nutrient accumulation was 993.6 kg·hm^–2 and the storage of N, P, K, Ca and Mg was 203.5, 23.0, 146.9, 553.6 and 66.6 kg·hm^–2, respectively. Results indicated obvious effects of site conditions on biomass productivity and nutrient accumulation of Q. acutissima plantations. Moreover, the nutrient accumulation coefficient of Q. acutissima was higher, while the nutrient concentration of litterfall was lower in the poor site than in the rich site. Therefore, adaptation of Q. acutissima to poor soil conditions involved increased nutrient uptake, increased internal nutrient cycling and reduced nutrient loss through litterfall.