Maintenance of a living understory enhances soil carbon sequestration in subtropical orchards.

Orchard understory represents an important component of the orchards, performing numerous functions related to soil quality, water relations and microclimate, but little attention has been paid on its effect on soil C sequestration. In the face of global climate change, fruit producers also require techniques that increase carbon (C) sequestration in a cost-effective manner. Here we present a case study to compare the effects of understory management (sod culture vs. clean tillage) on soil C sequestration in four subtropical orchards. The results of a 10-year study indicated that the maintenance of sod significantly enhanced the soil C stock in the top 1 m of orchard soils. Relative to clean tillage, sod culture increased annual soil C sequestration by 2.85 t C ha(-1), suggesting that understory management based on sod culture offers promising potential for soil carbon sequestration. Considering that China has the largest area of orchards in the world and that few of these orchards currently have sod understories, the establishment and maintenance of sod in orchards can help China increase C sequestration and greatly contribute to achieving CO2 reduction targets at a regional scale and potentially at a national scale

Soil carbon stock in four subtropical orchards as affected by understory management (UM), orchard type (OT), and their interaction.

<p>Values are means + SE of three replications. <i>F</i> values and <i>P</i> values are from two-way ANOVAs. <i>P</i> values <0.05 are shown in bold.</p

Soil total potassium content in four subtropical orchards as affected by understory management.

<p>Values are means + SE of three replications. <i>T</i> values and <i>P</i> values are from paired <i>t</i>-tests.</p

Understory vegetation management in orchard systems in Guangdong Province, southern China: (A) Sod culture and (B) Clean tillage.

<p>The image used in the figure is not the original image used in the study and only used for illustrative purposes.</p

Soil total phosphorus content in four subtropical orchards as affected by understory management.

<p>Values are means + SE of three replications. <i>T</i> values and <i>P</i> values are from paired <i>t</i>-tests.</p

Soil organic carbon content in four subtropical orchards as affected by understory management.

<p>Values are means + SE of three replications. <i>T</i> values and <i>P</i> values are from paired <i>t</i>-tests.</p

Soil total nitrogen content in four subtropical orchards as affected by understory management.

<p>Values are means + SE of three replications. <i>T</i> values and <i>P</i> values are from paired <i>t</i>-tests.</p

Effects of understory management on the economic costs (A) and benefits (B) in three subtropical orchards.

<p>Effects of understory management on the economic costs (A) and benefits (B) in three subtropical orchards.</p