黄土高原旱作麦田沟垄集雨种植模式下土壤呼吸及其组分的时空变化特征

Soil respiration is an important part of the terrestrial carbon cycle, which is the main way of terrestrial ecosystem carbon return to atmosphere and influences global climate change significantly. Loess Plateau is an important source of atmospheric CO2, but also one of important area for agricultural production in China. Plastic－covered ridge and furrow planting (PRFP) regarded as a promising water－saving agricultural technique of rainwater harvesting, has been paid more attentions due to the water shortage in Chinese Loess Plateau. Under conditions of PRFP’s planting pattern, soil water content available and heat characteristics and root characteristics, etc have been improved, which in turn may affect soil respiration and its components. However, the response of soil respiration and its components to water content and heat characteristics and root characteristics, etc has not been sufficiently studied. Therefore, the present study carries out in PRFP’s winter wheat field of the Loess Plateau, with flat wheat fields as control. The present study aim to (1) determine the dynamics change of water content and heat of soil, and root characteristic, etc under PRFP or under different ratios of ridge to furrow; and (2) identify spatiotemporal changes of the soil respiration and it components under PRFP, and its relationships with water content and heat of soil and root characteristics. The present study will provide theoretical guidance for currently assessment of CO2 emissions while maintaining high water-use efficiency in Loess Plateau.

土壤呼吸是陆地碳循环的重要组成部分，也是陆地生态系统碳返回大气的主要途径，它显著影响全球气候变化。黄土高原旱作农田是我国大气CO2的重要来源，也是我国重要的粮食生产基地之一。针对我国黄土高原旱区水资源严重不足，形成了我国旱区极具特色的沟垄集雨栽培技术体系，该技术作为一种高效集雨措施已被广泛运用。该模式通过改善农田土壤水热等性状，促进了作物根系的生长，进而影响农田土壤呼吸及其组分。然而该模式下土壤呼吸及其组分对土壤水热及根系性状的响应机制尚不明确。为此，本项目以黄土高原沟垄集雨种植麦田为研究对象，以平作麦田为对照，研究沟垄集雨模式及不同沟垄比对土壤呼吸及其组分的影响，并进一步探讨其与土壤水热等性状和小麦根系性状的相关关系。本项目旨在揭示沟垄集雨种植模式下旱作麦田土壤碳排放特征，探索该模式下高效节水低碳型种植方案，为发展黄土高原旱作麦田低碳稳产技术模式提供依据。

农田生态系统是大气中CO2的主要来源之一，研究农田碳排放对于降低大气CO2浓度的增加，并缓解全球气候变化具有重要的生态意义。黄土高原旱作农田是我国大气CO2的重要来源，也是我国重要的粮食生产基地。目前我国黄土高原旱区水资源严重不足，因此形成了我国旱区极具特色的沟垄集雨栽培技术体系，该技术体系已经成为了一种高效的集雨措施，并已被广泛运用。本项目以黄土高原沟垄集雨种植麦田为研究对象，以平作麦田为对照，明确了沟垄集雨种植模式可延长水分利用期，显著提高水分利用效率和产量，具有良好的生态效益和经济效益。阐明了旱作麦田土壤呼吸及其组分的时空变化规律，及其受土壤相关性状和根系性状的影响机制。基于沟垄集雨种植模式下不同沟垄比，研究了冬小麦的土壤呼吸动态变化，及其与土壤温度和水分相关关系，明确了异养呼吸与土壤总呼吸呈现出的季节性变化，并阐明了籽粒产量、水分利用效率、麦田生态系统碳平衡和单位产量CO2累积量对该种植模式下不同沟垄比的响应机制，揭示了该模式下高效节水低碳型种植方案，为发展黄土高原旱作麦田低碳稳产技术模式提供依据。