碱化草地多途径利用对土壤质量的影响

发布时间：2018-04-29 04:12

本文选题：土壤质量指数 + 土地利用方式　；参考：《中国科学院大学(中国科学院东北地理与农业生态研究所)》2017年博士论文

【摘要】：土壤是最重要的自然资源之一,是人类赖以生存和发展的物质基础,其质量好坏直接关系到区域生态安全和社会经济的可持续发展。土地利用和管理对土壤中众多的生态过程都具有非常重要的影响,往往决定着土壤质量变化的程度和方向。作为一种极为敏感和脆弱的土壤资源,盐碱土受土地利用方式的影响远高于其它土壤类型。因此,分析不同土地利用方式对盐碱土土壤质量的影响,对于我们科学管理和利用土壤资源,优化土地利用方式,促进农牧业的可持续发展具有重要意义。本文以松嫩碱化草地中的五种土地利用方式(自然恢复草地、人工羊草地、人工羊草割草地、人工苜蓿地、玉米地)为研究对象,从土壤的盐碱特征、养分特征、碳组分特征和微生物特征四个方面全面分析土地多途径利用对土壤质量的影响,结果表明:(1)各土地利用方式下,土壤总盐含量在1.10~2.30 g kg-1间波动。土地利用方式对土壤水溶性阴离子含量、总盐含量、p H值和总碱度影响不大,而对土壤水溶性阳离子含量、电导率和钠吸附比有一定影响。四种草地利用方式下,0~10 cm土层中土壤Na+含量、电导率和钠吸附比明显低于玉米地,而在10~50 cm土层中则高于玉米地。土壤电导率与p H值间呈极显著的对数回归关系,当土壤电导率小于350μS cm-1时,土壤p H值随电导率的增加而增加,而当土壤电导率大于350μS cm-1时,土壤pH值则基本维持在10.00左右。(2)各土地利用方式下,土壤全量养分和速效养分含量的变化有所不同。与玉米地相比,四种草地利用方式中土壤全氮(N)、全磷(P)和全钾(K)含量较高,土壤速效氮(AN)和表层速效磷(AP)含量较低,而土壤速效钾(AK)和下层土壤速效磷(AP)含量变化不明显。土壤养分元素化学计量比的变化在不同土地利用方式间具有一定的规律性。由于土壤有机碳含量的提高,导致四种草地利用方式中土壤的C:N、C:P和C:K比明显高于玉米地。施肥提高了玉米地中的养分含量,从而使得土壤中N:P、N:K和P:K比与草地利用方式无明显差异,而速效AN:AP、AN:AK和AP:AK比则表现为玉米地高于四种草地利用方式。(3)草地恢复提高了土壤有机碳和无机碳的含量。与玉米地相比,苜蓿地、羊草割草地、羊草地和自然恢复草地0~50 cm土层土壤有机碳含量分别提高了0.95、0.98、1.73和1.56 g C kg-1;而无机碳含量分别提高了2.14、1.78、0.88和1.46 g C kg-1。四种土壤易氧化有机碳组分中,极不稳定有机碳组分(F1)占有机碳的百分比最大(40.80%~49.70%),而稳定有机碳组分(F3)占有机碳的百分比最小(11.00%~15.50%),表明研究区内土壤主要以极不稳定有机碳组分为主。与玉米地相比,羊草割草地、羊草地和自然恢复草地中F1组分占有机碳的比例较低,而F2和F3组分占有机碳的比例较高,表明研究区内草地恢复不仅促进了土壤有机碳的截获,还提高了土壤有机碳的稳定性。(4)草地恢复显著提高了土壤中活性碳组分的含量。与玉米地相比,苜蓿地、羊草割草地、羊草地和自然恢复草地中0~10 cm土层土壤活性碳的几何平均数分别提高了34.42%、21.31%、16.39%和22.95%;而10~20 cm土层土壤活性碳的几何平均数分别提高了41.03%、23.08%、7.69%和41.03%。同时,土壤酶的活性也显著提高。与玉米地相比,苜蓿地、羊草割草地、羊草地和自然恢复草地中0~10 cm土层土壤酶活性的几何平均数分别提高了65.35%、44.09%、40.94%和52.76%;而10~20 cm土层土壤酶活性的几何平均数分别提高了76.92%、50.77%、67.69%和64.62%。相关性分析结果表明土壤有机碳、土壤易氧化有机碳和土壤微生物量碳与土壤酶活性间具有极显著的相关关系,而土壤可溶性有机碳与土壤酶活性间的相关性相对较弱。(5)松嫩碱化草地土壤质量评价的最小数据集中包括土壤有机碳含量(SOC)、过氧化氢酶活性(CAT)、总碱度(TA)、惰性有机碳含量(F4)和微生物量碳含量(MBC)5个土壤指标,在这5个土壤指标中,SOC的权重最大,CAT和TA次之,F4和MBC最小。4个土壤质量指数均能准确的反应出土地利用方式对土壤质量的影响,但由于土壤质量指数SQI-3在不同土地利用方式间的差异更明显,且变异性更大,能更敏感的反映出土地利用方式变化的影响,因此更适合研究区内土壤质量的评价。草地恢复显著改善了研究区内土壤的质量。4个土壤质量指数的结果表明苜蓿地、羊草地和自然恢复草地中土壤质量均较高,但考虑到本研究中苜蓿种植年限较短(仅2年)且其本身作为优质牧草具有较高的经济价值,因此认为在研究区内土壤条件较差的地区种植苜蓿是一种“双赢”的土地利用方式。
[Abstract]:Soil is one of the most important natural resources, and it is the material basis for human survival and development. Its quality is directly related to regional ecological security and the sustainable development of social economy. Land use and management have very important effects on many ecological processes in the soil, which often determine the degree of soil quality change and the degree of soil quality change. Direction. As a very sensitive and fragile soil resource, the influence of the saline alkali soil on the land use is much higher than that of other soil types. Therefore, the influence of different land use methods on the soil quality of saline alkali soil is analyzed, for the scientific management and utilization of soil resources, the optimization of land use mode and the sustainable development of agriculture and animal husbandry. In this paper, five kinds of land use methods in Songnen alkaline grassland (natural grassland, artificial sheep grassland, artificial Leymus chinense grassland, artificial alfalfa land, corn land) are studied in this paper. The soil's salt and alkali characteristics, nutrient characteristics, carbon component characteristics and microbiological characteristics are comprehensively analyzed in four aspects of land use to soil. The effect of soil quality showed that: (1) the total soil salt content fluctuated between 1.10~2.30 g kg-1 under various land use ways. The land use mode had little influence on the content of soluble anion, total salt content, P H value and total alkalinity, but had a certain influence on the content of water soluble cation, electrical conductivity and sodium adsorption ratio of soil. Four kinds of grassland utilization were used. The soil Na+ content, electrical conductivity and sodium adsorption ratio in the 0~10 cm soil layer were significantly lower than that in corn land, but higher in the 10~50 cm soil layer than in the maize land. The soil conductivity and P H value showed a very significant logarithmic regression relationship. When the soil conductivity was less than 350 u S cm-1, the P H value of soil increased with the increase of electrical conductivity, while the soil conductivity was large. At 350 S cm-1, the soil pH value was basically maintained at about 10. (2) the changes of soil total nutrient and available nutrient content were different under each land use mode. Compared with the corn land, the content of total nitrogen (N), total phosphorus (P) and total potassium (K) in the use of corn land was higher, and the content of soil available nitrogen (AN) and surface available phosphorus (AP) was low. The change of soil available potassium (AK) and lower soil available phosphorus (AP) content was not obvious. The change of soil nutrient element chemical measurement ratio has certain regularity between different land use ways. Because of the increase of soil organic carbon content, the soil C:N, C:P and C:K ratio in the four grassland utilization ways are obviously higher than that of corn land. The nutrient content in the corn land, so that the soil N:P, N:K and P:K were not significantly different from the way of grassland utilization, while the quick effect AN:AP, AN:AK and AP:AK ratio were higher than the four grassland utilization ways. (3) the grassland restoration improved the soil organic carbon and the inorganic carbon content. Compared with the corn land, alfalfa, Leymus chinensis grassland, sheep The soil organic carbon content in the 0~50 cm soil layer of grassland and natural grassland was increased by 0.95,0.98,1.73 and 1.56 g C kg-1, respectively, while the content of inorganic carbon increased by 2.14,1.78,0.88 and 1.46 g C kg-1. four soil readily oxidizing organic carbon components, and the most unstable organic carbon component (F1) was the largest percentage of organic carbon (40.80%~49.70%), and stable. The percentage of organic carbon component (F3) occupies the smallest percentage of carbon (11.00%~15.50%), indicating that the soil in the study area mainly is extremely unstable organic carbon component. Compared with the corn land, the proportion of F1 components in the sheep grass and natural grassland is lower than that of the corn land, and the proportion of F2 and F3 components is higher, indicating that the study area is in the study area. Grassland restoration not only promoted the interception of soil organic carbon, but also improved the stability of soil organic carbon. (4) grassland recovery significantly increased the content of active carbon components in soil. Compared with corn land, the geometric average of active carbon in 0~10 cm soil layer of alfalfa land, Leymus chinensis, sheep grassland and natural grassland was increased by 34.4 2%, 21.31%, 16.39% and 22.95%, while the geometric average of the soil active carbon in 10~20 cm soil increased 41.03%, 23.08%, 7.69% and 41.03%., and the activity of soil enzyme increased significantly. Compared with the corn land, the geometric mean of the enzyme activity in the alfalfa, Leymus Leymus meadow, the sheep grassland and the natural recovery grassland was increased respectively. 65.35%, 44.09%, 40.94%, and 52.76%, and the geometric mean of soil enzyme activity in 10~20 cm soil increased 76.92%, 50.77%, 67.69% and 64.62%. showed that soil organic carbon, soil easy to oxidize organic carbon and soil microbial biomass carbon have a very significant correlation with soil enzyme activity, and soil soluble organic carbon. The correlation between soil enzyme activity and soil enzyme activity is relatively weak. (5) the minimum data concentration of soil quality evaluation in Songnen alkaline grassland includes soil organic carbon content (SOC), catalase activity (CAT), total alkalinity (TA), inert organic carbon content (F4) and microbial biomass carbon content (MBC) in 5 soil indexes, and SOC has the largest weight in these 5 soil indexes, CAT And TA time, F4 and MBC minimum.4 soil mass index can accurately reflect the effect of land use mode on soil quality, but because the difference of soil quality index SQI-3 between different land use ways is more obvious, and the variability is greater, it can be more sensitive to reflect the influence of land use change, so it is more suitable for the research area. The results of soil quality.4 soil quality index in the study area showed that the soil quality of alfalfa land, sheep grassland and natural restoration grassland were higher, but considering that the planting years of Alfalfa in this study were shorter (only 2 years) and it had higher economic value as high quality pasture. Therefore, planting alfalfa in the poor soil conditions in the study area is a "win-win" land use mode.

【学位授予单位】：中国科学院大学(中国科学院东北地理与农业生态研究所)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S151.9

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