木荚红豆人工林凋落物的养分动态特征

Nutrient Dynamics of the Litter in Ormosia xylocarpa Plantation

探讨了福建三明莘口教学林场 3 4年生的木荚红豆人工林凋落物的养分特征及其动态 .结果表明 :凋落物各组分中 N、P、K、Ca、Mg含量差异显著 ,其月动态也不同 .1999年 ,木荚红豆人工林通过凋落物归还土壤的 N、P、K、Ca、Mg分别为 61.5 68、1.766、2 3 .2 19、3 3 .92 9、6.60 4kg· hm- 2 ,落叶是养分归还的主要组分 ,木荚红豆 N和 K年归还量明显比针叶林的大 ,这对维持林地的长期生产力具有重要意义 ;凋落物的 N、P、K、Ca、Mg总归还量间的月动态相似 ,均在 3月和 8月出现高峰 ,以 3月最高 ,以 1月最低 ;各组分养分归还量的月动态与总归还量略有不同 ,养分总归还量的季节变化模式为春季 >夏季≈秋季 >冬季 .

This paper deals with the nutrient characteristics and dynamics of the litter in a 34 year old Ormosia xylocarpa plantation located in Xinkou Teaching Forest Farm, Sanming, Fujian Province. The results show that the litter's concentration of N, P, K, Ca and Mg elements differs significantly among fractions, and monthly dynamics of N, P, K, Ca and Mg elements in fractions are also different from each other; that in 1999 the annual nutrient return through litter amounts respectively to 61.568 kg·hm -2 N, 1.766 kg·hm -2 P, 23.219 kg·hm -2 K, 33.929 kg·hm -2 Ca, and 6.604 kg·hm -2 Mg, and the main return of nutrients is through leaf litter; and that N and K return are obviously higher than coniferous forest, which benefits the maintenance of long term site productivity in the stand. The monthly dynamics of total nutrient return are similar among N, P, K, Ca and Mg elements, which peak in March and August, highest in March and lowest in January. The monthly dynamics of nutrient return among fractions are different to those of total nutrient return. Seasonal dynamics of total nutrient return through litter are in the order of spring>summer≈autumn<winter in the stand.