生物埂护坡上黄花根系分布特征及其对土壤养分的影响

Effect of Hemerocallis root system distribution characteristics on soil nutrients in terrace banks planted for hillslope protection

以川东丘陵区的梯田生物埂为研究对象,选择生物埂护坡上种植的黄花和生物埂网格内土壤为研究内容,为明确4种不同种植年限黄花根系分布特征及其对土壤养分的影响,通过野外调查和室内实验相结合的研究方法,分析了生物埂护坡上黄花根系分布特征、生物量与土壤养分之间差异性和相互关系。结果表明,随着种植年限的增长,黄花根长、根量、根表面积和根体积等指标均增加,4年生黄花根系垂直分布明显比其他3种种植年限的大,分别为185.3cm、17 133条、237.5cm2、301.2cm3和158.9cm。根系水平分布由于受到网格大小的限制而出现差异性。4种不同种植年限黄花根系平均生物量的大小顺序依次为:4a>3a>2a>1a,不同生长年限不同土壤层内根系的生物量也存在一定的差异。黄花根系形态不但影响植物本身的生长,还影响其保土培肥效果,3、4年生黄花根系土壤养分含量均比1、2年生黄花高,且种植植物的样地比对照裸坡地养分含量高,不同种植年限同一土层的土壤养分含量有显著性差异,土壤全氮、有效氮和有效钾含量均与黄花根系指标有显著的相关性,说明黄花根系的水土保持作用有保留土壤养分的能力。研究结果可为川东丘陵区的梯田生物埂的草本选择和土壤养分改良方面提供理论依据和实际应用参考价值。

Terrace banks in the east Sichuan hilly area which were planted with Hemerocallis citrina for slope protection were studied together with soil in bank grids to understand root distribution characteristics and their effect on soil nutrients. Four different planting years of Hemerocallis, were used in field investigations and in- door experiments with a combination of research methods. The differences and relationships between root dis- tribution characteristics, biomass and soil nutrients on terrace banks were analysed. With an increasing age af- ter planting, root length, root volume, root surface area and root volume indexes increased; The root vertical distribution of 4-year-old Hemerocallis were significantly higher than in younger plants. Their values over years one to four were 185.3 cm （17,133 items）, 237.5 emz, 301.2 cma and 158.9 cm respectively. The root system distribution levels were different due to the restrictions of the grid size. In the four different planting years of Hemerocallis, the average root biomass size sequences were： 4a〉3a〉2a〉1a. There was different growth in different soil layers and also some differences of root biomass. The Hemerocalgis root morphology not only affected the growth of the plant itself, but also affected soil fertilization. Root and soil nutrients were higher under three or four years of Hemerocallis than under 1 or 2 years of Hemerocallis, and those index in the bare plots, soil nutrient content were significantly difference between different plant ages in the same soil layer. Total N, available N and available P contents and the Hemerocallis root indicators were significantly correlated. It appears that the Hemerocallis roots have the ability to change the soil nutrients through their soil and water conservation properties. The research results could be used for choosing herbs and improving soil nu- trients in the east Sichuan hilly area terrace banks and to provide a theoretical basis and practical reference value.