Purpose

Diversification practices such as intercropping in woody cropping systems have recently been proposed as a promising management strategy for addressing problems related to soil degradation, climate change mitigation and food security. In this study, we assess the impact of several diversification practices in different management regimes on the main carbon fluxes regulating the soil carbon balance under semiarid Mediterranean conditions.

Methods

The study was conducted in two nearby cropping systems: (i) a low input rainfed almond (Prunus dulcis Mill.) orchard cultivated on terraces and (ii) a levelled intensively irrigated mandarin (Citrus reticulata Blanco) orchard with a street-ridge morphology. The almond trees were intercropped with Capparis spinosa or with Thymus hyemalis While the mandarin trees were intercropped with a mixture of barley and vetch followed by fava bean. Changes caused by crop diversifications on C inputs into the soil and C outputs from the soil were estimated.

Results

Crop diversification did not affect soil organic carbon stocks but did affect the carbon inputs and outputs regulating the soil carbon balance of above Mediterranean agroecosystems. Crop diversification with perennials in the low-input rainfed woody crop system significantly improved the annual soil C balance in the short-term. However, crop diversification with annual species in the intensively managed woody crop system had not effect on the annual soil C balance.

Conclusions

Our results highlight the potential of intercropping with perennials in rainfed woody crop systems for climate change mitigation through soil carbon sequestration.

中文翻译：

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半干旱地中海条件下作物多样化对雨养和灌溉木本种植系统土壤碳通量和平衡的短期影响

目的

最近提出了木本作物系统间作等多样化做法，作为解决与土壤退化、减缓气候变化和粮食安全有关的问题的有前景的管理战略。在这项研究中，我们评估了不同管理制度中的几种多样化做法对地中海半干旱条件下调节土壤碳平衡的主要碳通量的影响。

方法

该研究在附近的两个种植系统中进行：(i)在梯田上种植的低投入雨养杏仁 ( Prunus dulcis Mill.) 果园和 (ii)具有街道山脊形态的平整集约灌溉柑橘 ( Citrus reticulata Blanco) 果园。杏仁树与刺槐或百里香间作，而柑橘树与大麦和野豌豆的混合物间作，然后是蚕豆。估算了作物多样化对土壤碳输入和土壤碳输出造成的变化。

结果

作物多样化不影响土壤有机碳储量，但确实影响了调节地中海以上农业生态系统土壤碳平衡的碳输入和输出。在低投入雨养木本作物系统中种植多年生植物的作物多样化在短期内显着改善了年度土壤碳平衡。然而，在集约化管理的木本作物系统中，一年生物种的作物多样化对一年生土壤碳平衡没有影响。

结论

我们的研究结果强调了在雨养木本作物系统中与多年生植物间作通过土壤碳固存减缓气候变化的潜力。