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对首个轮伐期内I-69杨人工林养分循环的定位试验结果表明:(1)速生期叶片养分年平均适宜范围值:N(2.98%3.37%)>Ca(2.26%2.95%)>K(0.65%0.73%)>Mg(0.35%0.46%)>P(0.11%0.13)%),属喜N、Ga树种。(2)速生期叶片养分的年、月变异极显著,林木生长规律一致,叶片对养分吸收、积累、分配与转移的动态变化反映了体内养分循环的特性。林木生物量分配顺序各年都相同:干>枝>侧根>主根>干皮>主根皮,叶随林龄增加递减;养分分配速生期为:侧根>枝>干>干皮>主根>主根皮,后期枝、干大于侧根,叶随林龄增加递减,但养分分配比叶高于干。生物养分量的积累与分配与林木生长一致。(3)该森林生态系统内养分循环速率:生长前期为0.47,后期为0.28;养分利用率也不同,前期生产1t干物质需要的主要养分量分别为:N:7.6 kg,Ca:4.97 kg,K:1.89 kg,Mg:0.84 kg,P;0.26 kg,后期则为N:4.3 kg,Ca:6.34 kg,K:1.39 kg,Mg:1.14 kg,P:0.18 kg。人工林采伐后年平均移出养分量占土壤相应年平均速效养分量为:N:36.80%,P:52.8%,K:19.73%。支出较大。但是土壤养分供给水准较高,在该森林生态系统中,以林木和土壤为主导的养分循环仍处于动态平衡的良性循环之中。
The results of the experiment on the nutrient cycling of I-69 Yang-Plantations in the first rotation showed that: (1) The average annual suitable nutrient values of leaf nutrients in fast-growing period were N (2.98% 3.37%)> Ca (2.26% 2.95% K (0.65% 0.73%)> Mg (0.35% 0.46%)> P (0.11% 0.13)%). (2) The annual and seasonal variation of leaf nutrient in fast-growing period were extremely significant, and the growth pattern of trees was consistent. The dynamic changes of leaf nutrient absorption, accumulation, distribution and transfer reflected the characteristics of nutrient cycling in the body. The distribution order of forest biomass was the same in all years: stem> branch> lateral root> main root> dry bark> main root bark, with the decreasing of forest age; the rapid distribution of nutrient allocation was: lateral root> branch> stem> , Late branches, stems larger than the lateral roots, with increasing declining in age, but the distribution of nutrients than leaves higher than dry. The accumulation and distribution of biological nutrients is consistent with the growth of trees. (3) The nutrient cycling rate in this forest ecosystem was 0.47 in the early growth stage and 0.28 in the late stage. The nutrient utilization rate was also different. The main nutrients required for producing 1t dry matter in the early stage were N: 7.6 kg, Ca: 4.97 kg, K: 1.89 kg, Mg: 0.84 kg, P; 0.26 kg, late N: 4.3 kg, Ca: 6.34 kg, K: 1.39 kg, Mg: 1.14 kg, P: 0.18 kg. The average annual available nutrient content of the annual average annual removal of nutrients after harvesting of artificial forests is: N: 36.80%, P: 52.8%, K: 19.73%. Spending more. However, the soil nutrient supply level is relatively high. In this forest ecosystem, the nutrient cycle dominated by forest and soil is still in a virtuous cycle of dynamic equilibrium.