水稻秸秆-薄膜连续叠加覆盖对三叶鬼针草的控制效果

入侵植物三叶鬼针草(Bidens pilosa L.)严重危害我国农林畜牧业的生产。为探究生态高效控制三叶鬼针草的方法,开展了水稻秸秆与塑料薄膜相结合覆盖控制入侵杂草的研究。试验在以三叶鬼针草和马唐Digitaria sanguinalis(L.)Scop.]为主的自然杂草荒地进行,设置不同稻秆覆盖量(0kg·m~(-2)、1kg·m~(-2)、1.5kg·m~(-2)),于冬季进行稻秆覆盖,春季在稻秆覆盖的基础上覆盖薄膜。通过测定秸秆覆盖中期(2月12日)和薄膜覆盖中期(4月12日)的午间土壤温度、土壤相对含水量和近地表空气温湿度等环境指标和杂草生物量、种子萌发量、杂草群落结构和土壤种子库等群落指标,探究该方法控制入侵杂草的效果和机制。结果表明:冬季水稻秸秆覆盖显著降低了草地午间土壤温度、近地表空气温度、三叶鬼针草生物量和种子萌发量、优势杂草盖度和从属种的种类和数量;覆盖1.5 kg·m~(-2)稻秆的处理对各类指标的影响程度均大于1 kg·m~(-2)的处理。春季叠加薄膜覆盖导致浅层土壤高温干燥、近地表空气高温高湿;叠加薄膜覆盖处理使三叶鬼针草的土壤种子密度在0～5cm的土层内显著低于未做覆盖处理的对照,降低了79.49%;叠加薄膜覆盖处理的入侵杂草全部死亡且无种子萌发。说明冬季采用水稻秸秆覆盖,春季再叠加覆盖薄膜能有效防控三叶鬼针草的生长蔓延,在薄膜覆盖之前,覆盖1.5 kg·m~(-2)稻秆的处理对三叶鬼针草的防控效果要好于1 kg·m~(-2)的处理,在薄膜覆盖处理后,两个稻秆覆盖量处理对三叶鬼针草的防控效果均达到100%。本研究结果可为不同季节采用不同的控制方法及其组合模式防控入侵杂草的扩散提供参考。

Effect of continuous overlay mulching of rice straw-plastic film on control of invasive plant Bidens pilosa L.

The invasive plant, Bidens pilosa L., has extensively damaged the agricultural, forestry, and animal husbandry industries in China. Combining rice straw and plastic film mulching may be an ecological and efficient control method and was investigated in this study. Three straw mulching amounts (0 kg·m^-2, 1 kg·m^-2, and 1.5 kg·m^-2) were used, which was performed during winter followed by overlaid film mulching in spring. The environmental indicators (i.e., soil temperature, soil relative water content, surface air temperature, and relative humidity) and community indicators (i.e., weed biomass, seed germination amount, weed community structure, and soil seed bank) were measured in the middle periods both of straw mulching and film mulching. The results showed that rice straw mulching in winter significantly reduced the midday soil temperature, surface air temperature, B. pilosa L. biomass, seed germination amount, the dominant weed species coverage, and the number of subordinate weed species. The 1.5 kg·m^-2 treatment had the greatest effect. When film mulch was overlaid in spring, the temperatures of the shallow soil and surface air all increased, the humidity of shallow soil decreased, while the surface air humidity increased. The seed density of B. pilosa L. in 0-5 cm soil layer mulched by film was significantly decreased by 79.49% compared to non-film mulched. Overlaid film mulching after rice straw mulching, all B. pilosa L. died, and no seeds germinated. Rice straw mulching in winter followed by film mulching in spring can effectively prevent and control B. pilosa L. growth. This study provides an alternative method to prevent and control the spread of invasive weed species in different seasons.