首页分享水氮耦合处理对毛白杨纸浆林生长及土壤水养特征影响

水氮耦合处理对毛白杨纸浆林生长及土壤水养特征影响

来源：花匠小妙招时间：2026-02-20 03:05

摘要：

目的: 明确毛白杨纸浆材培育末期的最佳灌溉施肥策略，为不同时期水肥管理提供依据，也为解决长期灌溉施氮造成水资源浪费和土壤酸化等问题提供参考。方法: 以华北平原沙地的三倍体毛白杨为研究对象，采用增广试验设计滴灌水氮耦合试验，设置3 种灌水处理（W20、W33、W45）和 4种施氮水平（N0、NL、NM、NH）,研究第5个生长季内（4—10月）各水氮处理的叶面积指数（LAI）、土壤体积含水率（SVWC）的时空动态变化以及生长季末林木生长、林地土壤养分特征。结果: 1）培育末期，经过4年滴灌水氮耦合培育，不同水氮条件下林木生长、林地蓄积和林地生产力无显著差异。2）滴灌水氮耦合并未改变整个生长季LAI的变化趋势，受风灾（6月1日发生）影响，LAI总体呈双峰状，分别在5月30日和7月15日前后达到峰值。3）春季（5月）W20处理主要增加根区土壤表层（0~50 cm）水分，W33和W45处理则主要增加100~180 cm深度土壤水分；夏季（7月）灌溉能够增加0~180 cm深度土壤体积含水率，且W20处理对土壤水分的补充优于W33和W45处理；秋季（10月）停灌后，在W20和W33处理下深层土壤水分得到补充，而秋季的表层土壤相比春、夏季变得更为干燥。4）毛白杨林地土壤养分主要积累在浅土层（0~40 cm土层），浅土层土壤有机质和全氮含量对水氮耦合的响应弱于有效磷，其中灌溉对有效磷的积累作用大于施肥；且在水分充足的条件下（W20和W33灌溉下），施氮量的增加将抑制土壤磷含量的积累。5）土壤速效磷含量与林木胸径之间具有显著正相关，滴灌水氮耦合措施可调控土壤磷含量，进而影响林木生长。结论: 连续4年滴灌水氮耦合对毛白杨纸浆材培育末期林木生长及林地生产力无显著促进作用，且在灌水较多的水平下（W20和W33），高水平施氮（NM和NH）可能降低土壤有效磷积累，抑制林木生长。综合考虑经济成本和生态安全，在相近立地条件下，短轮伐期毛白杨纸浆材培育第5年停止施肥，保持充分灌溉（土壤水势?20 kPa时灌溉），土壤水分和养分维持在较高水平，实现地力可持续。

关键词: 水氮耦合, 毛白杨, 纸浆材培育末期, 林木生长, 土壤水养特征

Abstract:

Objective: Long-term irrigation and nitrogen application can cause a waste of water resources and soil acidification, leading to ecological security problems. This study aims to clarify the optimal irrigation and fertilization strategy for the late stage of Populus tomentosa pulpwood cultivation, so as to provide a basis for water and fertilizer management in different periods of short-rotation P. tomentosa pulpwood and also provide reference for solving problems such as water resource waste and soil acidification caused by long-term irrigation and nitrogen application. Method: The triploid P. tomentosa in the sandy land of the North China Plain was taken as the research subject, and an augmented experimental design was employed to conduct a drip irrigation water-nitrogen coupling experiment. Three irrigation treatments (W20, W33, W45) and four nitrogen application levels (N0, NL, NM, NH) were set up to investigate the spatiotemporal dynamics of the leaf area index (LAI) and soil volumetric water content (SVWC) under different water-nitrogen treatments during the fifth growing season (April to October), as well as the tree growth and soil nutrient characteristics at the end of the growing season. Result: 1) At the end of the cultivation of P. tomentosa pulp wood, after 4 years of drip irrigation water and nitrogen coupling, there was no significant difference in forest growth, forest stock and forest productivity under different water and nitrogen conditions. 2) The water-nitrogen coupling of drip irrigation did not change the changing trend of LAI throughout the growing season. However, due to the impact of the wind disaster (occurred on June 1), LAI showed a bimodal pattern, reaching peaks around May 30 and July 15. 3) In spring (May), the W20 irrigation treatment (when the soil water potential was –20 kPa) mainly increased the moisture in the root zone soil surface (0?50 cm), while the W33 and W45 irrigation treatments (when the soil water potential was –33 kPa and –45 kPa) mainly increased soil moisture at 100?180 cm. In summer (July), irrigation was able to increase 0?180 cm depth SVWC. The W20 supplemented soil moisture better than the W33 and W45 treatments. After irrigation was stopped in autumn (October), the deep soil moisture was replenished under W20 and W33 treatments, while the surface soil in autumn became drier than that in spring and summer. 4) Soil nutrients in P. tomentosa forestland mainly accumulated in the shallow soil layer (0?40 cm). The response of soil organic matter and total nitrogen content in the shallow soil layer to water-nitrogen coupling was weaker than that of available phosphorus. Among them, irrigation had greater effect on the accumulation of available phosphorus than fertilization. And under sufficient water conditions (W20 and W33 irrigation), the increase in nitrogen application inhibited the accumulation of soil phosphorus content. 5）There was a significant positive correlation between soil available phosphorus content and tree diameter at breast height. Thus, drip irrigation water-nitrogen coupling measures can regulate soil phosphorus content and affect the growth of forest trees. Conclusion: Water-nitrogen coupling for 4 consecutive years has no significant promotion effect on tree growth and forest productivity at the late stage of the cultivation of P. tomentosa pulpwood. Moreover, under the levels of heavy irrigation (W20 and W33), high-level nitrogen fertilization (NM and NH) may reduce the soil available phosphorus accumulation and inhibit forest growth. Comprehensive consideration of economic costs and ecological security, it is recommended that under similar site conditions, fertilization should be stopped in the fifth year of short-rotation P. tomentosa pulp cultivation and sufficient irrigation should be maintained (irrigation threshold is ?20 kPa), so that soil moisture and nutrients can be maintained at a higher level to achieve sustainable soil fertility.

Key words: coupling effects of water and nitrogen fertilizer, Populus tomentosa, the final stage of pulp material cultivation, forest tree growth, soil hydroponic characteristics

中图分类号:

S718.43