| 摘要: |
| 【目的】了解外源氮、磷添加后云南松苗木各器官及土壤中氮、磷、钾化学计量比的变化特征，为云南松苗木培育过程中养分的合理管理提供依据。【方法】以2年生云南松苗木为试材，设置氮、磷配施试验，每种肥料设置3个施肥水平，氮肥的施用水平为0，0.4和0.8 g/株，磷肥的施用水平为0，0.8和1.6 g/株，共9个施肥处理组合。施肥后2，4，6个月分别测定苗木根、茎、叶及土壤的氮(N)、磷(P)、钾(K)含量，计算N∶P、N∶K、K∶P，探讨施肥对云南松苗木 土壤氮、磷、钾化学计量比的影响。【结果】施肥处理后2，4，6个月，9个施肥处理组合的云南松苗木根、茎、叶平均N∶P分别为2.85～4.30，3.60～5.12和5.18～6.65，总体上表现为氮受限，其中根的平均N∶P以氮肥0.8 g/株+磷肥0.8 g/株处理最小，茎、叶的平均N∶P以氮肥0.4 g/株+磷肥0.8 g/株处理最小；平均K∶P分别为3.72～5.87，5.04～7.26和5.62～7.71，均以氮肥0.4 g/株+磷肥0.8 g/株处理最小；平均N∶K分别为0.71～0.78，0.71～0.74和0.89～0.93，总体上均以氮肥 0.4 g/株处理最大。根、叶N∶P、K∶P随苗木的生长呈现降低趋势，茎N∶P、K∶P表现为先降低后升高的趋势；根、叶N∶K随苗木的生长呈现出先降低后增加的趋势，茎N∶K呈现增加趋势。施肥后2,4,6个月各施肥处理组合土壤的平均N∶P、N∶K和K∶P分别在3.48～4.58，0.70～0.74，4.93～6.52内波动，随着时间推移，N∶P、K∶P呈现先降低后增加的趋势，N∶K呈增加趋势。氮、磷配施改变了苗木与土壤的相关关系，且这种关系存在明显的时间变异，施肥处理后2个月内云南松苗木各器官与土壤化学计量间无明显的相关关系，而随时间延长，呈显著相关关系。【结论】综合来看，氮、磷配施改变了苗木及土壤的氮、磷、钾化学计量比，表现为降低了苗木及土壤的N∶P、K∶P，提高了苗木及土壤的N∶K。随着时间变化，N∶P、K∶P总体上呈现出降低的趋势，N∶K呈现出逐渐增加的趋势，表明氮限制有加剧趋势。 |
| 关键词: 苗木培育 云南松 氮、磷配施 化学计量比 |
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| 基金项目:国家自然科学基金项目(31860203)；云南省教育厅科学研究基金项目(2019Y0124) |
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| Effect of fertilization on stoichiometric ratio of nitrogen,phosphorus and potassium in Pinus yunnanensis seedling and soil |
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LI Yaqi,CHEN Lin,TANG Junrong,et al
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| Abstract: |
| 【Objective】This study investigated the changing characteristics of stoichiometric ratios of N,P and K in organs of Pinus yunnanensis seedlings and soil after addition of exogenous N and P to provide basis for rational management of nutrients during the cultivation of P. yunnanensis seedlings.【Method】Two-year-old seedlings of P. yunnanensis were selected for nine fertilization combinations of nitrogen and phosphorus.Nitrogen fertilizer levels were 0,0.4 and 0.8 g per seedling and phosphorus fertilizer levels were 0,0.8 and 1.6 g per seedling.Contents of nitrogen (N),phosphorus (P),and potassium (K) in root,stem and needle of seedlings and soil were measured 2,4 and 6 months after fertilization,and N∶P,N∶K and K∶P ratios were calculated to explore the effects of fertilization on stoichiometric ratios of N,P and K.【Result】The average N∶P ratios of root,stem and needle of P. yunnanensis seedling after 2,4 and 6 months were 2.85-4.30,3.60-5.12 and 5.18-6.65,respectively.It was indicated that the growth of seedlings was mainly restricted by N.The minimum N∶P ratio of root was in the treatment of 0.8 g N and 0.8 g P,while the minimum N∶P ratios of stem and needle were in the treatment of 0.4 g N and 0.8 g P.The average K∶P ratios of root, stem and needle were 3.72-5.87,5.04-7.26 and 5.62-7.71,with the minimum in treatment of 0.4 g N and 0.8 g P.The average N∶K ratios of root,stem and needle were 0.71-0.78,0.71-0.74, and 0.89-0.93,with the maximum values in treatments with 0.4 g N.N∶P and K∶P ratios of root and needle of P. yunnanensis seedling decreased with the growth of seedling,while N∶P and K∶P ratios of stem decreased firstly and then increased.N∶K ratios of root and needle of P. yunnanensis seedling decreased and then increased with the growth of seedling, and N∶K ratios of stem increased gradually.Average N∶P,N∶K and K∶P ratios of soil under different fertilization treatments were 3.48-4.58, 0.70-0.74 and 4.93-6.52,respectively.Soil N∶P and K∶P ratios decreased firstly and then increased over time,and N∶K ratios showed increasing trends.N and P combined application changed the correlations between seedlings and soil with significant spatial variations.There was no significant correlation in stoichiometry between organs of P. yunnanensis seedlings and soil within 2 months after fertilization,but the correlation became significant as time extended.【Conclusion】Combined application of N and P changed the stoichiometric ratio of seedling and soil.N∶P and K∶P ratios of seedling and soil were decreased, while N∶K ratios of seedling and soil were increased.As time extended,N∶P and K∶P ratios gradually decreased,while N∶K ratios gradually increased,indicating that N restriction was increasing. |
| Key words: seedling cultivation Pinus yunnanensis combined application of nitrogen and phosphorus stoichiometric ratio |
