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施肥是提高苗木质量的关键技术措施之一,其根本目的在于及时补充苗木生长所需的养分,促进进苗木生长,提升苗木成活率和造林成效[1]。因此,成为苗木培育长期以来的研究热点。目前,林木施肥研究多集中以氮、磷、钾配比施肥试验[2],虽控制精准,但并不适用于树种不同生长阶段的养分供给。指数施肥是由瑞典农业科技大学的Ingestad等于20世纪80年代[3]创立的“指数养分承载理论”发展而来,并经Timmer等一系列西方学者[4,5]的研究带动下,得到了广泛推广。该理论是指采用与相对生长率同步的养分增加率,即指数递增方式逐渐增加施肥量,从而实现苗木对肥料的稳定持续吸收,提高苗木养分承载量和竞争能力[6]。由于指数施肥遵循了苗木年生长发育阶段的需肥规律,不但促进高效积累,还能避免养分毒害等优点,逐渐成为国内外苗木培育的首选施肥技术[7]。
杂交新美柳(Salix matsudana × alba)是2003年从美国引进的柳树新品种,有研究证明该品种在南京地区生长表现良好[8,9],继承了亲本旱柳(S. matsudana)和白柳(S. alba)的许多优良特性,特别是抗风和耐盐碱的特性,且观赏性高,生长迅速,适宜开发为内陆、沿海等盐碱滩涂造林用材[10]。但目前国内对杂交新美柳苗木培育的研究尚处于探索阶段,缺乏完备的理论基础和技术支持,对其指数施肥的相关试验亦鲜见报道。本研究系统比较研究了基于不施肥、常规施肥及指数施肥模式下杂交新美柳在苗高、地茎和生物量上的差异,以期获得最优施肥模式,从而为提高苗木生长质量与肥料利用效率提供基础参考。
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试验选用生长相对一致的1年生杂交新美柳扦插容器苗,平均苗高45.1 ± 0.3 cm,平均地径3.51 ± 0.03 mm,试验前1个月将苗移栽至配有集水托盘的塑料花盆中,每盆1株。盆栽基质采用河沙:珍珠岩 = 1∶1。将定植好的盆栽苗放于苗床,置于80%遮阳网下缓苗1个月,于2021年6月中旬开始指数施肥试验,期间,每隔2周移动盆的位置防止边缘效应。
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试验采用随机区组设计,设置对照(CK)、常规恒量施肥(CF)和指数施肥(EF1、EF2、EF3、EF4)共6个处理,采用指数施肥模型[11],获得氮用量分别为0.0、5.0、1.0、3.0、5.0和8.0 g·株−1,对应的多元复合肥(N∶P∶K = 15∶15∶55)用量分别0.00、33.35、6.66、19.99、33.35和53.34 g·株−1。以不施肥为对照CK。每个处理9株苗,3个重复,每个重复3株(见表1)。
施肥处理
Treatment以N肥计各处理单株施肥量
Weight of Nitrogen per plant/(g·株−1)6月10日 7月10日 8月10日 9月10日 10月10日 合计 CK 0.00 0.00 0.00 0.00 0.00 0.00 CF 1.00 1.00 1.00 1.00 1.00 5.00 EF1 0.05 0.08 0.15 0.29 0.43 1.00 EF2 0.17 0.27 0.47 0.84 1.25 3.00 EF3 0.27 0.43 0.76 1.35 2.19 5.00 EF4 0.43 0.69 1.22 2.08 3.58 8.00 Table 1. Application time and level of N fertilizer for hybrid Salix matsudana × alba under different fertilization treatments
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待杂交新美柳生长季结束后,于2021年10月10日,选取大小均匀的苗木,每个处理各9株,用卷尺和数显游标卡尺测量苗木苗高及地径生长情况。待用去离子水洗净后,按照地上部分(枝叶)和地下部分(根系)分别剪下,盛于托盘中,放入烘箱内,设置条件为:105℃杀青30 min,85 ℃烘干48 h至恒质量,用精度为0.01 g电子天平测其干质量。
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采用Microsoft Excel 2013对试验数据进行描述统计及绘图。利用SPSS 18.0 对数据进行单因素方差分析(one-way ANOVA),选择LSD法进行多重比较分析。
Effects of Exponential Fertilization on Growth and Biomass Accumulation of Hybrid Salix matsudana × alba Seedlings
doi: 10.12172/202203110001
- Received Date: 2022-03-11
- Available Online: 2023-01-11
- Publish Date: 2023-02-25
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Key words:
- Hybrid Salix matsudana × alba /
- Exponential fertilization /
- Seedling cultivation /
- Biomass
Abstract: To clarify the effects of exponential fertilization on the growth and biomass of hybrid Salix matsudana × alba seedlings can provide a basis for the seedlings cultivation. Taking the cutting seedlings of one-year-old hybrid S. matsudana × alba as the research object, the pot experiment method was adopted, and six treatments including control (CK), conventional fertilization (CF) and exponential fertilization (EF1, EF2, EF3, EF4) were set up. Each fertilization interval was 30 days and fertilization was applied five times in total. The seedling height and ground diameter of the seedlings were measured every 30 days. After the growth, the biomass was measured. The results showed that under different fertilization treatments, the seedling height and ground diameter growth of S. matsudana × alba were quite different, and the seedling height growth of EF2 treatment was the largest, which was 36.40% higher than that of CF treatment. The ground diameter growth of EF1 treatment was the largest, which was 21.63% higher than that of CF treatment. The biomass of EF treatment was significantly higher than that of CF and CK, and EF2 treatment was the best. Compared with CK treatment, the biomass of whole plant, aboveground part and belowground part increased by 96.86%, 84.31% and 157.60%, respectively. In conclusion, the exponential fertilization with nitrogen application rate of 3.0 g per plant and multi-component compound fertilizer of 19.99 g per plant were suitable fertilization methods for the cultivation of one-year-old hybrid S. matsudana × alba.