不同农作措施对少花蒺藜草(Cenchrus pauciflorus Benth)种子库及其繁殖能力的影响

系统调查了天然草原及旱作农田2种典型生境中少花蒺藜草种子库动态, 并深入研究了施肥、灌溉、刈割及替代种植对少花蒺藜草种群繁衍扩张的影响。结果表明:从2种生境土壤种子库中共鉴定出12科24属25种植物;天然草原及旱作农田少花蒺藜草种子总储量分别达12 923 粒·m^-2和8 960 粒·m^-2, 分别占整个种子库的67.72%及79.74%;天然草原生境中少花蒺藜草种子主要集中分布在土壤上表层(0~2 cm), 占种子总量的45.71%, 而旱作农田生境中, 少花蒺藜草种子在土壤表层(0~2 cm)、中层(2~5 cm)、下层(5~10 cm)中分布差异不显著(P>0.05)。试验也表明, 低施肥量能显著提高少花蒺藜草结实量(P<0.05), 而中、高水平施肥处理少花蒺藜草结实量反而降低;随着灌溉浇水量增加, 少花蒺藜草结实量显著增加(P<0.05), 高水平浇水量结实量平均为2 562.8 粒·株^-1;刈割能有效抑制少花蒺藜草种群种子繁殖, 每周刈割1次, 抑制少花蒺藜草结实率为97.69%;替代种植向日葵、菊芋能极显著抑制少花蒺藜草生长及结实量(P<0.01)。

Effects of Different Cultivation Practices on the Amount of Seeds in the Soils and Seed Production of Cenchrus pauciflorus Bent

In the present study, the amount of Cenchrus pauciflorus Benth seeds in the soils of natural grassland and farmland was measured. The effects of fertilization, irrigation, plant-mowing and using replacement plant species on C. pauciflorus were analyzed. From seeds of pasture and dry farmland soils, a total number of 25 plant species were identified, which fell into 24 genera of 12 families. The number of seeds of C. pauciflorus per square meter reached 12 923 in natural pasture soils and 8 960 in dry farming soils, which was 67.72% and 79.74% of the total seeds, respectively, from the two types of soils. In dry natural pasture soils, the seeds of C. pauciflorus were mainly distributed on the top 0~2.0 cm layer, being 45.71% of the total seeds. In dry farmland soils, however, the numbers of C. pauciflorus seeds were not significantly different on the 0~2.0, 2.0~5.0 cm and 5.0~10.0 cm layers (P>0.05). Experiments showed that seed production increased significantly at the low-dosage of fertilizer application (P<0.05), but it was much lowered at the intermediate and high dosages of fertilizer treatment. The seed yield of C. pauciflorus was positively related to the amount of water application in irrigation and it was 2 562.8 seeds per plant. Plant-mowing suppressed seeds production of the weed and a reduction of 97.69% of seeds was observed by mowing the weed once a week. Planting sunflower (Helianthus annus L.) or Jerusalem artichoke (Helianthus tuberosus L.) suppressed the growth and seed yield of C. pauciflorus plants significantly (P<0.01).