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題名 | 薩而瓦多型銀合歡苗木在銨態及硝酸態氮源介質的生長= |
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作者 | 洪富文; 孔繁熙; 張淑玲; |
期刊 | 林業試驗所研究報告季刊 |
出版日期 | 19860900 |
卷期 | 1:1 1986.09[民75.09] |
頁次 | 頁1-8 |
分類號 | 436.27 |
語文 | chi |
關鍵詞 | 銀合歡; 氮源; Leucaena leucocephala; Nitrogen sources; |
中文摘要 | 我們用含有NO3-N/NH4-N不同比例(100/0, 80/20, 50/50, 20/80,0/100) 的 modified Hoaglond and Arnon (1938)營養液進行薩爾瓦多型銀合歡的砂耕栽培試驗,以判斷苗木對不同型態氮源的適應性。試驗為逢機區集設計,總共為5個處理X5個區集,每一處理單位為一盆矽砂中所含的一株苗木。 2個月大的苗木經過3個月的處理後,就苗高、地上部乾重、地下部乾重及全株乾重而言,以在NO3-/NH4-N的比率為80/20之營養液生長者最佳,在 100/0及50/50者次之,在20/80及0/100者最差。而就處理後苗高的生長歷線及抽測介質溶液的pH的變化而言,在NH4-N多的介質中,其溶液於培養液加入後快速酸化是抑制其生長的主要原因。 由於植物固氮作用亦將引起根域的酸化,同時,在pH值較低的土壤,其硝化作用可能較差,供給固氮植物生長所需的氮態將多為NH4-N,亦將使根域酸化而不利固氮植物的生長;而硝化作用高的高pH值土壤,亦因硝化過程中,產生H+離子,植物吸收NO3-N後釋出OH-或HCO3-的量及速度是否可緩和土壤的酸化,值得進一步探討。總之,長期經營固氮樹種將引起土壤酸化,進而影響其生長,使其生產力衰退的問題在薩爾瓦多型銀合歡林之經營上應加重視。 |
英文摘要 | In a sand culture, 5 kinds of mineral nutrient solution of modified Hoagland and Arnon (1938) with different NO3-N/NH4-N ratios (100/0, 80/20, 50/50, 20/80, 0/100) were applied to 2-month-old seedlings of Leucaena leucocephala, Salvado type for 3 months. One seedling in a pot was a treatment subject and each treatment was randomized in each of 5 blocks, with total 25 seedlings in this experiment. ANOVA analysis of the height, diameter at the ground, and aboveground, belowground and total seedling biomass at the end of treatment period, Showed that the seedling growth in the treatment of NO3-N/NH4-N ratio being 80/20 was best, that in NO3-N/NH4-N ratio being 100/0 and 50/50 was medium, and that in NO3-N/NH4-N being 20/80 and 0/100 was bad. The bad growth was mainly due to the rapid acidification by high NH4-N uptake of seedlings supplied with the culture solution of high NH4-N proportion of N source. Because N2-fixation in nodules and possibly high NH4-N content in low pH soils with low nitrification, rhizosphere of host plant would be acidified in the field as demonstated in this experiment. As a consequence, the growth of Leucaena would be further retarded by functional damage of root, which was caused by soil acidity and/or Al toxicity. In the soils of high nitrification, the production of H+ during nitrification may also acidify the soils, in the long run the decrease of leucaena growth is expected. The potential effect of these phenomena should be estimated and monitored in the field, and counter action should be taken into consideration in the management of leucaena plantations. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。