Background and aims

The decomposition of shoot and root litter has been extensively studied in natural ecosystems. Our understanding of the decomposition of plant litter including carbon (C) and nitrogen (N) release from root residues is still limited in intercropping. We addressed how C and N release from straw and root decomposition might be affected in maize/legume intercrops.

Methods

A decomposition experiment was conducted within a field experiment including two N rates (i.e. no-N and N-addition), three monocultures (maize, soybean, and peanut), and two intercrops (maize/soybean and maize/peanut). Following five retrievals of polyethylene litterbag in 341 days, we assessed the C and N loss (i.e. release) and the mixing effects of both straw and root residues.

Results

Straws released 38.32% more C and 43.59% more N than root residues across all crop species. Maize/peanut residues showed faster C and N release than maize/soybean residues. The release of C and N was asynchronous in both straw and root decomposition in maize/peanut intercropping. Straw mixtures of maize and legume released C faster than expected from monoculture straw. Litter functional (i.e. initial chemical traits) dissimilarity between maize and legume accelerated C and N release from the decomposition of straw, but not root, in maize/legume intercropping.

Conclusions

These results suggest that C and N release from maize/legume residues can be explained by both residue quality and litter functional dissimilarity. Our findings have important implications for the management of straw and root residues to reduce reliance on chemical fertilizers in intercropping.

中文翻译：

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凋落物功能差异加速了玉米/豆类间作中秸秆分解中碳和氮的释放，但不加速根的释放

背景和目标

在自然生态系统中，枝和根凋落物的分解已被广泛研究。我们对间作植物凋落物分解（包括根部残留物释放的碳（C）和氮（N））的理解仍然有限。我们讨论了玉米/豆类间作作物中秸秆和根分解中的碳和氮释放可能受到的影响。

方法

分解实验在田间试验中进行，包括两种施氮量（即不施氮和施氮）、三种单一作物（玉米、大豆和花生）和两种间作作物（玉米/大豆和玉米/花生）。在 341 天内五次回收聚乙烯垃圾袋后，我们评估了碳和氮的损失（即释放）以及秸秆和根残留物的混合效应。

结果

所有作物种类中，秸秆释放的碳比根部残留物多 38.32%，氮多 43.59%。玉米/花生残渣比玉米/大豆残渣释放更快的碳和氮。玉米/花生间作秸秆和根系分解过程中C和N的释放是异步的。玉米和豆类秸秆混合物释放碳的速度比单一栽培秸秆的预期要快。在玉米/豆类间作中，玉米和豆类之间凋落物功能（即初始化学性状）的差异加速了秸秆分解中的碳和氮的释放，但不是根部的释放。

结论

这些结果表明，玉米/豆类残留物中碳和氮的释放可以通过残留物质量和凋落物功能差异来解释。我们的研究结果对于管理秸秆和根残留物以减少间作对化肥的依赖具有重要意义。