黄土高原丘陵沟壑区土壤物理性质对苜蓿种植年限的响应

发布时间：2018-01-27 13:54

本文关键词： 黄土高原紫花苜蓿种植年限土壤物理性质水稳性团聚体土壤有机碳土壤容重　出处：《中国生态农业学报》2016年11期 　论文类型：期刊论文

【摘要】：西部黄土高原丘陵沟壑区是中国乃至世界上水土流失最严重的区域,以禾谷类作物单播为主的传统农业生产系统和过度耕作是引致水土流失的最主要原因。紫花苜蓿作为优良豆科牧草,在区域生态环境建设和产业结构调整中发挥着重要作用。因此,本研究通过设置在陇中黄土高原半干旱区的长期定位试验,以苜蓿草地(3 a、10 a、12 a)和农田(马铃薯地)为主要研究对象,探讨了土壤物理性质对于苜蓿种植年限的响应,为黄土高原雨养农业系统紫花苜蓿适宜种植年限的选择及苜蓿草地的可持续利用提供科学依据。结果表明,随着紫花苜蓿种植年限的加长,土壤表层呈容重降低、孔隙度增加的变化趋势,而下部土层变化不明显。苜蓿种植可以提高耕层0~30 cm土壤0.25 mm水稳性团聚体含量、平均重量直径(MWD)和几何平均直径(GMD),同时降低团聚体破坏率(PAD),且随种植年限的延长效果愈加明显。苜蓿种植一定年限后土壤总有机碳(TOC)和易氧化有机碳(ROOC)与农田差异明显,其中种植苜蓿土壤易氧化有机碳占总有机碳的比例为44%~57%,农田土壤易氧化有机碳比例占52%~68%,表明种植苜蓿不仅提高了土壤总有机碳含量,且改变了土壤有机碳的组成比例。与农田相比,苜蓿种植可改善土壤水分入渗性能,表现为随种植年限的延长呈现先增加后降低的趋势。黄土高原沟壑区种植苜蓿可以改善土壤有机质形态和物理结构,提高土壤渗透能力,但苜蓿种植年限以10 a为宜,10 a之后应该进行轮作换茬以维持雨养农业系统的可持续发展。
[Abstract]:The hilly and gully region of the western Loess Plateau is the most serious area of soil and water loss in China and the world. The main cause of soil and water loss is the traditional agricultural production system and overcultivation of cereal crops. Alfalfa is an excellent legume forage. It plays an important role in the construction of regional ecological environment and the adjustment of industrial structure. Therefore, through the long-term positioning experiment in semi-arid region of Longzhong Loess Plateau, the alfalfa grassland is used for 10 years. 12 a) and farmland (potato field) as the main research objects, the response of soil physical properties to alfalfa planting years was discussed. It provides scientific basis for the selection of suitable planting years of alfalfa and the sustainable utilization of alfalfa grassland in the rain-fed agricultural system of the Loess Plateau. The results show that with the increase of alfalfa planting years. The surface layer of the soil decreased in bulk density and the porosity increased, but the change of the lower soil layer was not obvious. Alfalfa planting could increase the content of 0.25mm water stable aggregate in 0 ~ 30cm soil. Mean weight diameters (MWD) and geometric mean diameters (GMD), while reducing the failure rate of aggregates (PAD). The effect of soil total organic carbon (TOC) and oxidized organic carbon (ROOC) after alfalfa planting for a certain number of years was more obvious than that in farmland. The percentage of oxidized organic carbon in alfalfa soil was 447.The ratio of easy oxidized organic carbon in cropland soil accounted for 52%. The results showed that planting alfalfa not only increased the content of soil organic carbon, but also changed the proportion of soil organic carbon. Compared with farmland, alfalfa planting could improve soil moisture infiltration performance. Alfalfa planting in the gully region of the Loess Plateau can improve the morphology and physical structure of soil organic matter and increase soil permeability. However, after 10 years of alfalfa planting, rotation should be carried out to maintain the sustainable development of rain-fed agricultural system.
【作者单位】：甘肃农业大学资源与环境学院;甘肃省干旱生境作物学重点实验室;
【基金】：国家自然科学基金项目(41461067,31171513) 国家科技支撑计划项目(2012BAD14B03) 甘肃省财政厅高校基本科研业务费项目(037-041014)资助~~
【分类号】：S152;S541.9
【正文快照】： 罗珠珠,主要从事土壤生态方面的研究。E-mail:luozz@gsau.edu.cn*This study supported by the National Natural Science Foundation of China(41461067,31171513),the National Key Technologies RDProgram of China(2012BAD14B03)and the Fundamental Research Funds of t

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