【作者】 刘克林；

【导师】 孙向阳； 康向阳；

【作者基本信息】 北京林业大学 ， 土壤学， 2009， 博士

【摘要】 本文以三倍体毛白杨(Populus tomentosa Carr)为研究对象,选择最适生的北京、河南及河北等三个地区,进行了林木叶片养分动态变化研究。采用正交试验设计方案在河北试验地进行了施肥试验。主要研究结果如下:与对照二倍体毛白杨比较,三倍体毛白杨无性系S11、S1、S6、S3、S7、S8、S4叶片N元素浓度均有所提高,说明多数三倍体毛白杨无性系与二倍体相比,对N素需求更多;研究的11个三倍体无性系叶片K元素浓度均高于对照,说明三倍体无性系对K素的需求均高于二倍体;而从叶片Ca元素浓度来看,11个三倍体无性系均低于对照,说明三倍体毛白杨对Ca素的需求量比二倍体小。三倍体毛白杨叶片养分浓度在一个生长季节内呈现出规律性动态变化。叶片养分浓度变化范围是:N 20.72～31.89g/kg,P 1.21～1.91g/kg,K 8.13～12.81g/kg,Ca 8.27～17.95g/kg,Mg 4.21～6.91g/kg。不论落叶前后,施肥处理三倍体毛白杨叶片中N、P、K、Ca浓度均高于不施肥处理,而Mg浓度低于不施肥处理。施P、K肥并不导致三倍体毛白杨对P、K的奢侈吸收。施肥显著增加了三倍体毛白杨的生物量,使得施肥处理林木中各主要元素的外循环通量均高于不施肥处理。由于施入了过磷酸钙,使得相当数量的Ca从干、枝、根转入叶片中。以三倍体毛白杨造林第3年7～10月份各施肥处理叶片养分元素浓度为依据,制定了DRIS营养诊断标准,取得了较高的诊断正确率。DRIS诊断的三倍体毛白杨叶片N、P、K营养元素浓度最佳比值范围分别为:N/P=19.116±1.270;N/K=3.054±0.289;K/P=6.356+0.651。利用7～10月份高产组的叶片N、P、K分析值制定了DRIS图解法及指数法营养诊断标准,并经各月份养分元素浓度进行回代检验,结果表明诊断精度较高。以诊断精度最高的9月份各处理为例,进行诊断指数的计算,结果与实际施肥状况较吻合,诊断正确率达到了80%以上。从施肥试验结果来看,3年生三倍体毛白杨林木对N、P、K元素需求次序为:N>K>P,这与三倍体毛白杨叶片营养DRIS诊断结果一致。不同生长状况下三倍体毛白杨叶片养分浓度差异较大,反映在各养分浓度变异系数较大,特别是低产林;其中Zn浓度变异系数最大,其高、中、低产林变异系数分别高达37.30%、48.37%和66.40%。除Mg外,其他养分浓度都有随林木产量的提高而升高的趋势。根据高产林叶片养分浓度平均值和标准差提出了三倍体毛白杨叶片养分浓度分级标准及临界指标:N 25.00g/kg,P 1.50 g/kg,K 8.00 g/kg,Ca 9.00 g/kg,Mg 4.00 g/kg,Fe 250 mg/kg,Mn 40 mg/kg,Cu 10mg/kg,Zn 30 mg/kg。林木生长量与叶片N、P、K浓度均存在显著的一元线性正相关关系,与Ca浓度线性正相关关系不显著,而与Mg浓度呈负相关。根据偏相关系数大小,得出叶片N、P、K浓度对林木生长量的影响程度为N>K>P。三倍体毛白杨不同生长指标对施肥反应的敏感性不同:材积>胸高断面积>胸径>树高。林木施肥后,肥效反应的初始时间为施肥后的第1年,即当年施肥就产生了肥效,促进了幼树的生长;最大肥效反应时间出现在施肥后的第2年,说明施肥第2年三倍体毛白杨对施肥反应最为敏感,且肥效也最大;施肥后的第3年,肥效反应有所下降。无论胸径还是树高,与对照相比都有不同程度的增值效应,其中胸径最大增长了18.796,树高最大增长了9.4%。不同施肥处理下,胸径、蓄积生长量均达到了极显著性差异。16个施肥处理,胸径连年生长量的变化规律完全一致,最大值均出现在第2年。树高连年生长量变化规律是:1～11、13～16处理,树高连年生长量最大值出现在第3年,而12处理则出现在第2年,比其他施肥处理最大值提前1年。综合考虑施肥3年后林木蓄积生长量以及钾肥施入量大小,选择处理8为最佳施肥方案,其具体肥料使用量为:尿素230g/株+过磷酸钙230g/株。更多还原

【Abstract】 The nutrients dynamics in the leaves of Triploid Populus tomentosa were studied in three most suitable growth areas of Hebei,Henan and Beijing.Fertilization experiments with an orthogonal design (L₁₆4⁵) were also conducted in the experimental plots located in Hebei Province.The main results were as follows:Compared with the control of duple clone,nitrogen concentrations in the leaves of Triploid clones S11,S1,S6,S3,S7,S8 and S4 were significantly higher.Significantly higher K concentrations and lower Ca concentrations were also found in all 11 triploid clones.Nutrients concentrations in the leaves of Triploid Populus Tomentos varied regularly in a growing season,with total N 20.72-31.89 g/kg,P 1.21-1.91 g/kg,K 8.13-12.81 g/kg,Ca 8.27-17.95 g/kg,and Mg 4.21-6.91 g/kg,respectively.No matter pre- or post- leaves fallen,higher N,P,K and Ca concentrations but lower Mg concentrations were found in the leaves of Triploid Populus Tomentos with fertilization than those without fertilization.The application of P and K fertilizers did not lead to the luxury uptake of P and K by Triploid Populus tomentosa.Fertilization significantly increased the biomass of Triploid Populus tomentosa and thus increased the flux of external cycling of major nutrients.The application of superphosphate made considerable quantity of Ca transfer from trunk,branch and root to leaves.Based on N,P and K concentrations in the leaves of Triploid Populus tomentosa from July to October in the third year after plantation,nutrition diagnosis standards of DRIS graphic and index methods were successfully established with high accuracy.The optimal N/P,N/K and K/P ratios were 19.116±1.270,3.054±0.289 and 6.356±0.651,respectively.Diagnostic accuracy reached 80%with the analytical data in September for return test.The nutrients requirement by Triploid Populus tomentosa was in the order of N>K>P,which was in accord with the actual application rate of fertilizers. Nutrients concentrations in the leaves of Triploid Populus Tomentos varied greatly in different growth status with higher coefficients of variation（CV）,especially in low-yield plantations.The highest CV was found for Zn concentration,which was 37.30%,48.37%and 66.40%for high-,medium-,and low-yield plantations,respectively.Except for Mg,nutrients concentrations in the leaves tended to increase with increasing tree yield.Based on the average and standard deviation of nutrients concentrations in the leaves of high-yield plantations,the classification standards and critical indices were put forward as follows:N,25.00g/kg;P,1.50 g/kg;K,8.00 g/kg;Ca,9.00 g/kg;Mg,4.00 g/kg;Fe, 250 mg/kg;Mn,40 mg/kg;Cu 10 mg/kg and Zn 30 mg/kg.There were significant positive linear correlations between tree growth and N,P,K concentrations in the leaves.The positive linear correlation between tree growth and Ca concentration in the leaves did not reach the significant level.A negative linear correlation between tree growth and Mg concentration was also found.According to the partial correlation coefficients,the effect of N,P,K concentrations in the leaves on tree growth was N>K>P.The responses of different growth indices of Triploid Populus tomentosa to fertilization varied in the order of volume > breast-height basal area > diameter at breast height > height.After fertilization, the initial response occurred in the first year of fertilization,and the greatest response appeared in the second year.The fertilization effect decreased in the third year.Tree DBH and height increment effects with fertilization were significant.The DBH increased by 18.7%,and height by 9.4%most compared with those without fertilization.There were very significant differences of the DBH and volume growth between different fertilization treatments.Changes of the DBH annual growth were completely consistent in 16 fertilization treatments,with the maximum values appearing in the second year.The maximum values of height annual growth appeared in the third year except for fertilization treatment 12,whose maximum value appeared in the second year.Taking the volume growth and potassium fertilizer into consideration,the best schemes of 4-year-old Triploid Populus tomentosa were:urea 230g/tree + superphosphate 150g/tree.更多还原