滴灌施肥下施氮量和施氮频率对毛白杨生物量及氮吸收的影响  

Effects of Nitrogen Application Rate and Frequency on Biomass Accumulation and Nitrogen Uptake of Populus tomentosa under Drip Fertigation

作　　者：席本野[1] 王烨[1] 贾黎明[1] Xi Benye Wang Ye Jia Liming(Key Laboratory of Silviculture and Conservation of Ministry of Education, Beijing Forestry University Beijing 100083)

机构地区：[1]北京林业大学省部共建森林培育与保护教育部重点实验室,北京100083

出　　处：《林业科学》2017年第5期63-73,共11页Scientia Silvae Sinicae

基　　金："十二五"国家科技支撑计划资助(2015BAD09B02);国家自然科学基金项目(31400532;31670625);中央高校基本科研业务费专项资金项目(BLX2013018)

摘　　要：【目的】为滴灌施肥下的毛白杨提供合理的氮(N)肥管理建议。【方法】以毛白杨(无性系B301)速生纸浆林(林龄3~5年)为研究对象,于2010—2012年研究施N量和施N频率对毛白杨生物量积累和N吸收的影响。试验设置为施N量115(N_(115)),230(N_(230))和345(N_(345))kg·hm^(-2)a^(-1)和施N频率[每年分4次施入(F4)和2次施入(F2)]所组成的6个滴灌施肥处理和1个只灌溉不施肥的对照处理(CK)。试验期间,对林木生长、生物量积累、N吸收量和土壤养分进行测定。【结果】自然条件下,3~5年生毛白杨林地土壤的表观矿化N量为23~42 kg·hm^(-2)a^(-1),CK林分N吸收量约为60 kg·hm^(-2)a^(-1),土壤供N量难以满足高产林分的N吸收量。滴灌施肥能明显促进毛白杨生长,其中,以施N量为115 kg·hm^(-2)a^(-1)、生长季内分4次施入处理(N_(115)F_4)最具生长优势,其2011和2012年林分总生物量分别达到33.9和45.5 t·hm^(-2),较CK分别显著提高42%和49%(P<0.05)。不同施N量水平对总生物量影响显著,2011年,N115处理总生物量显著大于N_(230)和N_(345)处理(P<0.05);2012年,N_(115)显著大于N_(345)处理(P<0.05),略大于N230处理(P>0.05)。施N频率对生物量未产生明显影响,但较高的施N频率(F_4)能提高林木年均N吸收量(P<0.05)。用二次回归方程拟合林分总生物量与施N量之间的关系,方程拟合效果较好(P<0.01,R2=0.482),由方程计算出最佳施N量为192 kg·hm^(-2)a^(-1),其90%置信区间为148~236 kg·hm^(-2)a^(-1)。【结论】滴灌施肥下,毛白杨人工林常规施N量(N345)并没有带来产量的增益效应,采用滴灌施肥技术能够比常规施肥技术减少肥料用量。施肥频率虽对产量没有影响,但采用较高的施N频率可提高林分的N吸收量,减少养分在土壤中的残留。3~5年生毛白杨人工林进行滴灌施N肥时,建议施N量为192 kg·hm^(-2)a^(-1),每年分4次施入土壤。[ Objective ] This study aimed to provide recommendations for N fertilizer management of Populus tomentosa under drip fertigation. [ Method] A field experiment was conducted in 2010 - 2012 （stand age of 3 - 5 years） to investigate the effects of nitrogen rate （NR） and application frequency （NF） on biomass accumulation and N uptake of P. tomentosa （clone B301） in a fast-growing pulp plantation. The experiment included six N fertigation treatments, which were a factorial combinations of three NR （ 115 （ N115 ） , 230 （ N230 ） and 345 （ N345 ） kg · hm ^-2a^-1 ） and two NF （ two （ F2 ） or four （F4 ） times per year）. A control treatment （0 N with irrigation, CK） was also included in the experiment. Diameter at breast height, height, biomass, N uptake and soil N were measured periodically during the experiment. [ Result] Under natural condition （ambient environment）, the soil N supply capacity （includes apparent N mineralization （23 -42 kg · hm ^-2a^-1 in the P. tomentosa plantation of age 3 -5） and soil inorganic N） could not provide P. tomentosa with adequate nutrient for optimal growth. The amount of apparent N mineralization was 23 - 42 kg · hm ^-2a^-1 in the plantation of age 3 - 5. The trees in CK incorporated nearly 60 kg · hm ^-2a^-1 from soil N sources, which could not maintain a high level of yield of P. tomentosa plantation. N fertigation showed a positive effect on tree growth, and especially trees under the Nit5 F4 treatment had the highest growth rate. Total biomass （TM） in the NH5 F4 treatment reached 33.9 and 45.5 t · hm-2 in 2011 and 2012, respectively, which were 42% and 49% significantly higher than that in CK （P 〈 0.05） , respectively. Variance in NR could significantly affect the TM of stand. In 2011 , the TM under N115 was significantly higher than that under N230 and N345 （ P 〈 0.05 ） , while in 2012 it was significantly higher than N345 （ P 〈 0.05） and not significantly higher than N230 （P 〉 0. 05）. NF sh

关 键 词：滴灌施肥 三倍体毛白杨 生物量 N吸收量 

分 类 号：S753.53[农业科学—森林经理学]