燕麦与不同作物间作对土壤线虫群落结构及作物产量的影响

Effects of intercropping oat with different crops on the community structure of soil nematodes and crop yields

  • 摘要: 间作是土地可持续利用的重要种植模式。土壤线虫作为土壤健康的指示生物, 可揭示地下生态系统的食物网功能。为探究燕麦不同间作模式对产量和土壤线虫群落的影响, 本试验分别设置燕麦单作、燕麦||大豆、燕麦||赤小豆、燕麦||马铃薯和燕麦||甘薯5个处理, 分析燕麦不同间作模式对作物产量以及土壤线虫的数量、多样性和群落结构的影响, 以筛选出较优的燕麦间作模式。结果表明: 相比单作, 间作模式在土地利用率和作物总产量方面有一定的优势, 其中燕麦||马铃薯间作模式最佳, 土地当量比(1.36)最高, 其次为燕麦||大豆间作模式, 土地当量比为1.29。4种燕麦间作模式均显著(P<0.05)降低了植物寄生线虫的相对丰度, 提高了食微线虫相对丰度, 优化了土壤线虫群落结构。燕麦||大豆间作模式下食微线虫比例最高(88.42%), 植物寄生线虫比例最低(6.31%), 且在多项生态指数中(瓦斯乐斯卡指数、线虫通路指数、多样性指数和均匀度指数)显著高于燕麦单作(P<0.05)。而燕麦||赤小豆间作模式下富集指数最高, 植食性线虫成熟度指数最低, 土壤线虫群落受干扰程度最低。速效钾与线虫通路指数呈极显著正相关(r=0.722**), 速效钾含量的提升可以使土壤有机质分解主要依靠细菌分解途径。综上, 间作种植模式可以优化土壤线虫群落结构, 改善土壤生态环境, 提高产量; 燕麦||大豆是该试验条件下最佳的间作模式。

     

    Abstract: Intercropping is an important planting method for the sustainable use of land resources, and soil nematodes are an indicator of soil health, which can reveal the function of food webs in underground ecosystems. To explore the effects of different intercropping patterns of oats on yield and soil nematode communities, five treatments were set up: oat monoculture, and intercropping systems of oat||soybean, oat||rice bean, oat||potato, and oat||sweet potato. The effects of different intercropping patterns of oats on crop yield and the number, diversity, and community structure of soil nematodes were analyzed to determine the best intercropping pattern. The results showed that, compared with monoculture, intercropping had certain advantages in terms of land utilization rate and total crop yield. The intercropping of oats and potatoes had the highest land equivalent ratio (1.36), Followed by the intercropping of oats and soybeans, the land equivalent ratio is 1.29. A total of 39 genera were identified, including 12 bacterivorous nematodes, 4 fungivorous nematodes, 13 plant-parasitic nematodes, and 10 omnivorous predatory nematodes. The four oat intercropping patterns significantly reduced the relative abundance of plant-parasitic nematodes, increased the relative abundance of beneficial nematodes (bacterivorous and fungivorous), and optimized the soil nematode community structure. Among them, the best intercropping pattern was oat and soybean, with the highest proportion of microbial-feeding nematodes (88.42%) and the lowest proportion of plant-parasite nematodes (6.31%). Additionally, the intercropping pattern of oat and soybean was significantly higher than that of oat monoculture (P<0.05) in multiple ecological indexes (Wasilewska index, nematode channel ratio, Shannon-Wiener index, and enrichment index), and was also the best among the four intercropping patterns. The enrichment index of oat and rice bean intercropping was the highest, and the plant parasite index was the lowest, indicating that the soil nematode community was the least disturbed. The enrichment index and structure index of each cropping pattern were lower than 50, and the soil nematode food web was in quadrant D, indicating that the soil environment was in a stressed state, the food web was degraded, and the soil nematode community was unstable at the experiment location. Pearson correlation analysis showed that soil nematode community ecological indices were correlated with soil physical and chemical properties. Organic matter was significantly negatively correlated with the evenness index (r=−0.635, P<0.05), significantly negatively correlated with the Shannon-Wiener index (r=−0.641, P<0.01), and significantly positively correlated with the plant parasitic index (r=0.633, P<0.05). There was a significant positive correlation between available K content and the nematode channel ratio (r=0.722, P<0.01), increasing available K content could change the decomposition pathway of soil organic matter and contribute more to the decomposition of soil organic matter. In conclusion, intercropping can optimize the soil nematode community structure, improve the soil ecological environment, and increase crop yield. Among the four intercropping patterns, oat and soybean intercropping were the best method, not only having the highest crop yield but also the most beneficial nematode community structure for soil health, which showed the strong production and ecological advantages of traditional Gramineae and Leguminosae intercropping.

     

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