配方施肥对杉木中龄林生长及土壤化学计量特征的影响

Effect of formula fertilization on growth and soil stoichiometric characteristics of middle-aged Cunninghamia lanceolata forest

[目的]通过比较不同施肥处理对杉木中龄林林木生长及土壤养分的影响,筛选杉木人工林培育的最佳施肥量与施肥配方。[方法]以15年生杉木人工林为研究对象,设置“3414”不完全处理(钾固定)、测土配方、测树配方以及微量元素平衡配方,共12种施肥处理。测定并分析施肥前后林木生长量变化及0~20 cm、20~40 cm和40~60 cm土层的土壤养分含量及其化学计量特征。[结果]施肥可有效促进杉木生长,其中处理10(N_(土)P_(土)K_(土),氮肥、磷肥和钾肥分别为140、370、60 g·株^(-1))和处理6(N_(2)P_(2)K_(2),氮肥、磷肥和钾肥分别为240、600、150 g·株^(-1))的林木生长效果最好。与CK(N_(0)P_(0)K_(0))相比,处理10的平均树高、胸径和单株材积增量分别提高58.5%、68.2%和100%,处理6分别提高53.4%、59.7%和88.9%。杉木树高生长与磷肥施入量呈显著正相关。施肥明显改变土壤化学计量特征,施肥后不同处理各土层土壤C∶N、C∶P和N∶P变化区间分别为6.83~15.16、25.42~108.84和2.78~11.63。磷是影响研究区土壤生产力的主要限制性因子。在改善土壤质量方面,处理10效果显著,表层土壤的全碳、全氮和全磷含量分别比CK提高37.33%、12.8%和37.5%,中层和深层土壤的全碳、全氮和全磷含量也都显著高于CK。[结论]测土配方施肥在促进杉木林木生长和改善林地土壤质量方面均具有显著效果,且肥料利用水平更高。

[Purpose]The goal of the study was to develop an optimal fertilization formula and dosage for the cultivation of Cunninghamia lanceolata plantation based on the growth status and soil stoichiometric characteristics under different fertilization treatments.[Method]The field experiment was performed on a 15-year-old C.lanceolata plantation in Shenkou Forest Farm,Sanming City.The experiment included 9 combinations of fertilization treatments by incomplete block design with nitrogen(N)and phosphorus(P)applied at 4 levels and the dosage of potassium(K)being constant.Another 3 treatments were developed from soil testing(named as T_(10)),nutrition characteristics of C.lanceolata(T_(11))and balanced formula supplemented with trace elements(T_(12)),respectively.Growth indices of the plantation were recoded before and after fertilization,and soil nutrient contents were measured at the depths of 0-20,20-40 and 40-60 cm,respectively,together with the interpretation of soil stoichiometric characteristics.[Result]The results showed that fertilization effectively boosted the growth of C.lanceolate:the promotive effects of T_(10)(N,P and K applied at rates of 140,370,60 g per tree)and T_(6)(N,P and K applied at rates of 240,600,150 g per tree)were the best,leading to 58.5%,68.2%and 100%growths in average tree height,diameter at breast height(DBH)and volume in T_(10),and 53.4%,59.7%and 88.9%growths of the above mentioned indices in T_(6),respectively.There was a significant positive correlation between height growth and the amount of P fertilizer.Fertilization exerted significant impacts on soil stoichiometric characteristics under the plantation,with the ratios of C∶N,C∶P and N∶P fluctuating between 6.83-15.16,25.42-108.84,and 2.78-11.63,respectively after fertilization.Correlation analysis revealed that P was the main limiting factor affecting soil productivity in the study area.Moreover,soil quality was furthest improved under T_(10),seeing 37.33%,12.8%and 37.5%growths in soil total carbon,total nitrogen and total phosphorus,respectively;soil fertility of the medium and deep layers were also better than their compartments in the control.[Conclusion]The fertilizer formula developed from soil testing contributed to the furthest forest growth,best soil quality and highest utilization efficiency of fertilizers among all the treatments,which is recommended for wider application in the cultivation and management of C.lanceolate plantation.