Dominance, evenness and diversity of weeds in the seedbank have been recommended as potential indicators for monitoring the sustainability of cropping systems. We aimed to investigate viable seed density and diversity in soil after 13 years of diversified cropping and nutrient management practices. The long-term field experiment comprised four cropping sequences: maize (Zea mays L.)–wheat (Triticum aestivum L.) (M-W), maize–wheat–mungbean (Vigna radiata L.) (M-W-Mb), maize–wheat–maize–chickpea (Cicer arietinum L.) (M-W-M-C) and pigeonpea (Cajanus cajan L.)–wheat (P-W) in main plots and three nutrient management regimes: without fertilisation (CT), recommended inorganic fertilisers (RDF) and integrated nutrient management (INM) in subplots. The importance value index (IVI), the sum of relative frequency, density and abundance, was used to measure how dominant a species was in a given treatment. The M-W rotation recorded a higher IVI of Phyllanthus niruri L. and Medicago denticulata L. compared with legume-based cropping (M-W-Mb, M-W-M-C and P-W). INM also resulted in higher IVI of these species than RDF in the 0–15 cm soil layer. The P-W rotation resulted in 33%–40% (at 0–7.5 cm), 16%–26% (at 7.5–15 cm) and 27%–36% (at 0–15 cm) higher seed density compared to the remaining rotations (expressed as the mean of other rotations). However, the sequence of seed density was INM = CT > RDF for the nutrient management. Weed species diversity (Shannon and richness indices) in the seedbank was higher in legume-based cropping than the M-W. The M-W rotation also had higher ecological dominance than legume-based rotations throughout the soil profile. Averaged across depths, RDF had 16% higher ecological dominance than the INM practice. Above-ground weed density in wheat at harvest was significantly lower in M-W-Mb and M-W-M-C than the M-W rotation indicating that weed pressure and competition in wheat are reduced when systems were diversified with mungbean and chickpea. However, the P-W rotation and INM can increase both weed seed density and species diversity compared with continuous cereal–cereal rotation (M-W) and chemical fertilisation (RDF) in the long term. Thus, diversification of M-W with legume (chickpea and mungbean) can be an important strategy to enhance species diversity vis-à-vis to reduce weed competition, herbicide inputs and avoiding the evolution of herbicide resistance.

中文翻译：

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豆科作物与化学施肥和综合施肥对杂草种子密度、多样性和群落结构的长期影响

种子库中杂草的优势度、均匀度和多样性已被推荐为监测种植系统可持续性的潜在指标。我们的目标是在经过 13 年的多样化种植和养分管理实践后调查土壤中可行的种子密度和多样性。长期田间试验包括四种种植序列：玉米（Zea mays L.）-小麦（Triticum aestivum L.）（MW）、玉米-小麦-绿豆（Vigna radiata L.）（MW-Mb）、玉米-小麦– 玉米 – 鹰嘴豆 ( Cicer arietinum L.) (MWMC) 和木豆 ( Cajanus cajanL.)–小麦 (PW) 在主地块和三种养分管理制度：不施肥 (CT)、推荐的无机肥料 (RDF) 和子地块中的综合养分管理 (INM)。重要性价值指数 (IVI)，即相对频率、密度和丰度的总和，用于衡量一个物种在给定处理中的优势程度。MW 轮换记录了Phyllanthus niruri L. 和Medicago denticulata的更高 IVIL. 与豆类作物（MW-Mb、MWMC 和 PW）相比。在 0-15 厘米土壤层中，INM 还导致这些物种的 IVI 高于 RDF。与其余种子相比，PW 轮作导致 33%–40%（0–7.5 cm）、16%–26%（7.5–15 cm）和 27%–36%（0–15 cm）更高的种子密度旋转（表示为其他旋转的平均值）。然而，对于养分管理，种子密度的顺序是 INM = CT > RDF。种子库中的杂草物种多样性（香农指数和丰富度指数）在豆类作物中高于 MW。在整个土壤剖面中，MW 轮作也比基于豆类的轮作具有更高的生态优势。平均跨深度，RDF 的生态优势比 INM 实践高 16%。MW-Mb 和 MWMC 中小麦收获时的地上杂草密度显着低于 MW 轮作，这表明当系统采用绿豆和鹰嘴豆多样化时，小麦中的杂草压力和竞争减少。然而，从长远来看，与连续谷物轮作 (MW) 和化学施肥 (RDF) 相比，PW 轮作和 INM 可以增加杂草种子密度和物种多样性。因此，豆科植物（鹰嘴豆和绿豆）的 MW 多样化可以成为增强物种多样性的重要策略，以减少杂草竞争、除草剂投入和避免除草剂抗性的演变。从长远来看，与连续谷物轮作 (MW) 和化学施肥 (RDF) 相比，PW 轮作和 INM 可以增加杂草种子密度和物种多样性。因此，豆科植物（鹰嘴豆和绿豆）的 MW 多样化可以成为增强物种多样性的重要策略，以减少杂草竞争、除草剂投入和避免除草剂抗性的演变。从长远来看，与连续谷物轮作 (MW) 和化学施肥 (RDF) 相比，PW 轮作和 INM 可以增加杂草种子密度和物种多样性。因此，豆科植物（鹰嘴豆和绿豆）的 MW 多样化可以成为增强物种多样性的重要策略，以减少杂草竞争、除草剂投入和避免除草剂抗性的演变。