Abstract:

To study the effects of intercropping with forage grasses on the composition and diversity of weed communities in an apple orchard in Nyingchi, Tibet, two annual grasses (Avena sativa L. and Vicia sativa L.) and two perennial grasses (Medicago sativa L. and Dactylis glomerata L.) were single sown or mixed sown, with grasses naturally growing after clear tillage used as a control. The weed communities were then surveyed in 2011 and 2022, respectively. A total of 33 weed species belonging to 31 genera and 17 families were found in the experimental plots in the two studied years. The dominant families were Gramineae, Leguminosae, Polygonaceae, and Asteraceae, and the dominant species were Pennisetum flaccidum Griseb., Eragrostis pilosa (L.) Beauv., Galinsoga parviflora Cav., Taraxacum mongolicum Hand.-Mazz., and Persicaria microcephala (D. Don) H. Gross. Intercropping with forage grasses led to a reduction in weed species richness and importance values of the dominant weed species, which were influenced by forage grass species and planting year. Intercropping also resulted in lower species diversity of the weed communities, with both planting year and cropping pattern significantly affecting community diversity and dominance. Weed control efficacy was higher for Gramineae forage compared to Leguminosae forage, and mixed sowing showed better results than single sowing treatment. The above findings suggest that the selection of forage grasses should be based on their growth period, with annual forages being more effective for short-term weed control and perennial forages being more suitable for long-term grass planting in orchards.

摘要：

以林芝市巴宜区苹果园杂草群落为研究对象，以清耕后自然生长植物为对照，研究了一年生箭筈豌豆（Avena sativa L.）、燕麦（Vicia sativa L.）和多年生紫花苜蓿（Medicago sativa L.）、鸭茅（Dactylis glomerata L.）牧草单播或混播对苹果园杂草群落组成和多样性的影响。结果显示：（1）调查期间共发现杂草17科31属33种，其中优势科为禾本科、豆科、蓼科和菊科，优势种为白草（Pennisetum flaccidum Griseb.）、画眉草（Eragrostis pilosa (L.) Beauv.）、小头蓼（Persicaria microcephala (D. Don) H. Gross.）、牛膝菊（Galinsoga parviflora Cav.）和蒲公英（Taraxacum mongolicum Hand.-Mazz.）；（2）牧草种植可以减少果园中杂草种类，降低优势杂草重要值，改变杂草群落结构，不同类型牧草在不同种植年限对杂草群落的影响存在差异；（3）不同间作牧草模式下杂草群落物种多样性有显著差异，但整体上较对照有所降低，种植年限与种植模式对群落多样性和优势度均有显著影响；（4）间作牧草有良好的杂草抑制效果，其中禾本科牧草的杂草防控效果优于豆科牧草，混播处理的杂草防控效果优于单播处理。研究结果表明，人工牧草的选择应考虑牧草生长年限，一年生牧草在短期内杂草防控效果较好，多年生牧草适宜长期种草的果园。