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    刘峰, 席本野, 戴腾飞, 于景麟, 李广德, 陈雨姗, 王杰, 贾黎明. 水肥耦合对毛白杨林分土壤氮、细根分布及生物量的影响[J]. 北京林业大学学报, 2020, 42(1): 75-83. DOI: 10.12171/j.1000-1522.20190222
    引用本文: 刘峰, 席本野, 戴腾飞, 于景麟, 李广德, 陈雨姗, 王杰, 贾黎明. 水肥耦合对毛白杨林分土壤氮、细根分布及生物量的影响[J]. 北京林业大学学报, 2020, 42(1): 75-83. DOI: 10.12171/j.1000-1522.20190222
    Liu Feng, Xi Benye, Dai Tengfei, Yu Jinglin, Li Guangde, Chen Yushan, Wang Jie, Jia Liming. Effects of water and fertilizer coupling on soil nitrogen, fine root distribution and biomass of Populus tomentosa[J]. Journal of Beijing Forestry University, 2020, 42(1): 75-83. DOI: 10.12171/j.1000-1522.20190222
    Citation: Liu Feng, Xi Benye, Dai Tengfei, Yu Jinglin, Li Guangde, Chen Yushan, Wang Jie, Jia Liming. Effects of water and fertilizer coupling on soil nitrogen, fine root distribution and biomass of Populus tomentosa[J]. Journal of Beijing Forestry University, 2020, 42(1): 75-83. DOI: 10.12171/j.1000-1522.20190222

    水肥耦合对毛白杨林分土壤氮、细根分布及生物量的影响

    Effects of water and fertilizer coupling on soil nitrogen, fine root distribution and biomass of Populus tomentosa

    • 摘要:
      目的杨树速生丰产林是我国主要的纸浆兼用材林,较低的水肥利用效率容易造成土壤退化、环境污染甚至林分产量下降。因此,迫切需要探究适宜的水肥耦合策略,实现可持续发展。本研究通过探讨不同水肥耦合处理对根区土壤氮分布、根系分布以及林木产量的影响,旨在筛选出适宜毛白杨人工林的最佳水肥耦合措施。
      方法以三倍体毛白杨为研究对象,设置3个灌溉水平:− 20 kPa(I20)、− 33 kPa(I33)、− 45 kPa(I45)和4个施N水平:0(F0)、120 kg/(hm2·a)(F120)、190 kg/(hm2·a)(F190)、260 kg/(hm2·a)(F260),并设置CK对照(不灌溉不施肥)。测定其全年的土壤NO3-N动态、细根分布以及生物量产量。
      结果(1) 施N量和灌溉量显著增加NO3-N运移、分布和深层累积量,其中I20F260处理NO3-N深层浸出现象严重,而I20F120处理浸出量最小。(2) 水肥耦合管理可使根系分布浅层化;其中N肥供应可改变根系分布规律,灌溉促使根系分布表层化;而根系生长对N的响应取决于灌溉水平,其中I20F260处理根长密度(RLD)显著高于其他处理(P < 0.05)。(3) 不同处理NO3-N含量、RLD和整株生物量(TB),彼此间存在显著相关性。其中,土壤NO3-N含量与RLD存在显著抛物线回归关系(P < 0.05);因此,土壤养分差异是造成细根分布差异的重要因素。0 ~ 10 cm、20 ~ 40 cm土层RLD与TB呈极显著的抛物线回归关系(P < 0.01);可见,0 ~ 10 cm、20 ~ 40 cm土层适量的RLD有利于提高林木产量。其中,I20F120水肥耦合处理,林木年均生物量最高。
      结论I20F120处理施N量是传统施N量的四分之一,且深层NO3-N浸出量最小,有效减轻对环境的污染;此外,能够形成适量的RLD,促进林木对土壤养分的吸收利用,并最终形成较高的林木产量和较高的水肥利用率等优点。因此推荐I20F120处理为砂地毛白杨人工林最佳水肥耦合措施。

       

      Abstract:
      ObjectiveFast-growing and high-yield poplar forest is the main pulp and timber forest in China. However, lower water and fertilizer use efficiency causes soil degradation, environmental pollution and even decline in forest yield. Therefore, it is urgent to explore appropriate water and fertilizer coupling strategies to achieve sustainable development. In this study, we investigated the effects of different water and fertilizer coupling treatments on the soil nitrogen distribution, root distribution and forest yield, aiming to screen out the optimal water and fertilizer coupling measures for the yield of Populus tomentosa plantation.
      MethodIn this experiment, triploid Populus tomentosa was used as the research object. Three irrigation levels: − 20 kPa (I20), − 33 kPa (I33), − 45 kPa (I45), four application N levels: 0 (F0), 120 kg/(hm2·year) (F120), 190 kg/(hm2·year) (F190), 260 kg/(hm2·year) (F260), and a CK control were set to determine the soil NO3-N dynamics, absorption root distribution and the biomass yield throughout the year.
      Result(1) The amount of N applied, and the amount of irrigation significantly increased the migration, distribution and deep accumulation of NO3-N. Among them, the deep leaching of NO3-N treated by I20F260 was serious, while the amount of leaching of I20F120 was the smallest. (2) The coupling of water and fertilizer can make the root distribution shallow; the supply of N fertilizer can change the distribution of root system, and the irrigation promotes the surface distribution of roots; the response of root growth to N depends on the irrigation level, and I20F260 treating the root length density (RLD) was significantly better than other treatments (P < 0.05). (3) NO3-N content, RLD, and whole plant biomass (TB) of different treatments showed significant correlations with each other. There was a significant parabolic regression relationship between soil NO3-N content and RLD (P < 0.05). Therefore, soil nutrient difference is an important factor in the difference of fine root distribution. The RLD and TB in 0 – 10 cm and 20 – 40 cm soil layers showed a very significant parabolic regression relationship (P < 0.01). It can be seen that an appropriate amount of RLD in 0 – 10 cm, 20 – 40 cm soil layer is beneficial to increase forest yield. In this study, the annual average biomass of forest trees was highest with I20F120 water and fertilizer coupling treatment.
      ConclusionThe amount of N applied by I20F120 is one quarter of the traditional amount of N applied, and the deep NO3-N leaching amount is the smallest, which effectively reduces the pollution to the environment; in addition, it can form an appropriate amount of RLD to promote the absorption and utilization of nutrients, and ultimately the formation of higher forest yields and higher water and fertilizer utilization. Therefore, I20F120 is recommended as the best water and fertilizer coupling measure.

       

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