| 摘要: |
| 【目的】探究氮添加对轻木（Ochroma lagopus）人工林生长及其根和土壤养分含量的影响，为轻木人工林施肥管理提供一定的理论基础。【方法】以景洪农场的2年生轻木人工林为试验材料，采用完全随机区组设计，设置尿素和缓释肥2种氮肥，每种氮肥纯氮（N）用量设置低（92 kg/hm2）、中（136 kg/hm2）、高（184 kg/hm2）3个水平，通过计算，共设置6个施氮处理，分别为低尿素300 g/株（N1）、中尿素450 g/株（N2）、高尿素600 g/株（N3）、低缓释肥300 g/株（H1）、中缓释肥450 g/株（H2）、高缓释肥600 g/株（H3），以不施氮肥作为对照（CK），共7个处理，测定不同处理轻木的生长指标（树高、胸径）和根可溶性糖、淀粉和非结构性碳水化合物（NSC）、C、N、P含量及土壤全氮（TN）、全磷（TP）、全钾（TP）含量，计算根C∶N、C∶P和N∶P和土壤N∶P、N∶K和K∶P，对以上指标进行相关性、表型可塑性以及主成分分析，在此基础上采用隶属函数对7个处理的综合表现进行了评价。【结果】各施氮处理轻木的树高、胸径相对增量均高于CK，其中H2处理树高、胸径相对增量最大，分别达到了26.67%和27.66%。与CK相比，除N1与H2处理外，其余施氮处理轻木的根可溶性糖含量均显著下降，各施氮处理根淀粉与NSC含量总体下降；各施氮处理根C含量无显著变化，根N、P含量增加。各施氮处理土壤TN、TP、TK含量均增加，且在同等施氮量下，缓释肥处理的土壤TN含量显著高于尿素处理。相关性分析结果显示，树高、胸径与土壤TN、土壤TK、根N、根P呈极显著正相关，根N、根P和根N∶P与土壤TN呈极显著正相关，根P与土壤TK呈显著正相关。氮添加条件下轻木生长指标和根与土壤养分的表型可塑性指数为0.092~0.433，其中土壤TN、土壤N∶P、根N、根C∶N、根可溶性糖和根可溶性糖∶淀粉的表型可塑性指数均较大。主成分分析结果显示，在主成分1和2中，不同指标的权重系数差异较大，其中根N含量权重系数较高，土壤N∶P影响较大。隶属函数分析结果表明，H2处理的隶属函数平均值最高，为0.732；其次分别是H3（0.682）、N2（0.533）、H1（0.530）、N1（0.490）、N3处理（0.445）；CK的最低，仅为0.297。【结论】氮添加对轻木生长及根和土壤养分含量有明显影响，其中以中等缓释肥处理（H2）效果较优。 |
| 关键词: 轻木 氮添加 土壤养分 根系养分 树高 胸径 |
| DOI：10.13207/j.cnki.jnwafu.2025.12.006 |
| 分类号: |
| 基金项目:国家自然科学基金项目（32071688） |
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| Growth,root and soil nutrient content of Ochroma lagopus plantations in response to nitrogen addition |
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WEN Chengjing1, WU Junwen1, ZHAO Zhijuan1, GU Jianyao1, DU Guanben2, LIANG Wen3
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1.College of Forestry,Southwest Forestry University,Kunming,Yunnan 650224,China;2.College of Materials and Chemical Engineering,Southwest Forestry University,Kunming,Yunnan 650224,China;3.Jinghong Farm Co.,LTD.of Jinghong City,Xishuangbanna,Yunnan 666303,China
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| Abstract: |
| 【Objective】This research aimed to investigate the effect of nitrogen addition on the growth of Ochroma lagopus plantation forests and their root and soil nutrient contents,to provide a certain theoretical basis for the fertilization management of O.lagopus plantation forests.【Method】With the 2-year-old O.lagopus plantation forest in Jinghong Farm as the experimental material,a completely randomized block design was adopted.Two kinds of nitrogen fertilizers (urea and slow-release fertilizers) were used,and three levels of pure nitrogen (N) dosage were set for each nitrogen fertilizer,namely low dosage (92 kg/hm2),medium dosage (136 kg/hm2), and high dosage (184 kg/hm2).By calculation,a total of six nitrogen treatments were set:low urea 300 g/plant(N1),medium urea 450 g/plant (N2),high urea 600 g/plant (N3),low slow-release fertilizer 300 g/plant (H1),medium slow-release fertilizer 450 g/plant (H2),and high slow-release fertilizer 600 g/plant (H3).No nitrogen fertilizer treatment was used as the control (CK).With a total of seven treatments,the growth indexes (tree height,diameter at breast height), root soluble sugars,starch and non-structural carbohydrates (NSC),C,N,P contents and soil total nitrogen (TN),total phosphorus (TP) and total potassium (TP) contents were determined for different treatments.Root C∶N,C∶P and N∶P and soil N∶P,N∶K and K∶P were calculated.Correlation,phenotypic plasticity and principal component analyses were conducted on the above indicators,and the subordinate function was used to evaluate the overall performances of seven treatments. 【Result】The relative increments of tree height and diameter at breast height (DBH) in all N application treatments of O.lagopus were higher than that of CK,with the highest relative increment of tree height(26.67%) and DBH(27.66%) observed in H2 treatment.Compared with CK,the root soluble sugar content of all the nitrogen application treatments of O.lagopus,except N1 and H2 treatments,decreased significantly,and the root starch and NSC content of all the nitrogen application treatments decreased in general.No significant difference was observed in root C content under nitrogen application treatments,and the root N and P content increased.The soil TN,TP,and TK content under nitrogen application treatments increased,and with the same amount of nitrogen application,the soil TN content of the slow release fertilizer treatments was significantly higher than that of the urea treatment.The results of correlation analysis showed that tree height and diameter at breast height were highly significantly and positively correlated with soil TN,soil TK,root N and root P.Root N,root P and root N∶P were highly significantly and positively correlated with soil TN,and root P was significantly positively correlated with soil TK.The phenotypic plasticity indices of O.lagopus growth indexes and root and soil nutrients under nitrogen addition ranged from 0.092 to 0.433,with larger phenotypic plasticity indices for soil TN,soil N∶P,root N,root C∶N,root soluble sugars and root soluble sugars∶starch.The results of principal component analysis showed that the weight coefficients of different indexes varied greatly in principal components 1 and 2,with higher weight coefficients for root N content and greater influence of soil N∶P.The results of affiliation function analysis showed that H2 treatment had the highest mean value of affiliation function(0.732),followed by treatmenr H3 (0.682),N2 (0.533),H1 (0.530),N1 (0.490),N3 (0.445),respectively,with the lowest value (0.297) observed in CK.【Conclusion】Nitrogen additions showed significant impact on the growth of O.lagopus and on the nutrient content of roots and soil,of which the medium slow-release fertilizer treatment (H2) showed the better effect. |
| Key words: Ochroma lagopus nitrogen addition soil nutrients root nutrient tree height diameter at breast height |
