北京密云油松人工林生态系统N、P、K养分循环

Nutrient cycling of N,P and K in a plantation ecosystem of Pinus tabulaeformis in Miyun District,Beijing

对北京密云水库库西试验区的33年生油松人工林N、P、K养分循环进行了研究。结果表明:油松人工林不同器官中N、P、K含量顺序为针叶>树枝>树根>树干;油松人工林N、P、K的积累量分别为323.87、53.33、235.19kg/hm2;油松人工林凋落物中N、P、K的归还总量为18.00kg/(hm2.a),占归还总量的36.32%,降水中N、P、K的归还总量为31.56kg/(hm2.a),占归还总量的63.68%;油松人工林生态系统从土壤中吸收N、P、K的总量为126.58kg/(hm2.a),其中77.02kg/(hm2.a)存留于油松人工林中,49.56kg/(hm2.a)通过淋溶和凋落物归还土壤;油松人工林N、P、K的吸收系数为N>P>K,利用系数为N>K>P,循环系数为K>N>P,周转期为11.94、48.45、11.02年,富集系数为5.20、1.85、0.09。

Cycling of N,P and K in a Pinus tabulaeformis plantation was investigated in Miyun County of Beijing.The contents of N,P and K in different organs of P.tabulaeformis follow the order of leaves > living branches > stems > roots.The standing crops of N,P and K in the plantation amount up to 323.87,53.33 and 235.19 kg/hm2,respectively.The annual returns of the three elements through litterfall and rain leaching amount to 18.00 and 31.56 kg/(hm2·a).These two pathways contribute to 36.32% and 63.68% of total return in the plantation.The annual total absorption of N,P and K is 126.58 kg/(hm2·a),in which the annual retention is 77.02 kg/(hm2·a),and the annual return is 49.56 kg/(hm2·a).The absorption coefficient and the utilization coefficient are in the order N > P > K and N > K > P.The cycling coefficient follows the order K > N > P.The recycling periods of N,P,K are 11.94,48.45 and 11.02 yrs,respectively.The enrichment coefficients of N,P and K are 5.20,1.85 and 0.09,respectively.