不同管理措施对土壤水气传输性质的影响研究

发布时间：2018-05-30 11:04

本文选题：土壤饱和导水率 + 土壤导气率　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：为了研究不同管理措施对土壤水气传输性的影响,分别以位于黄土塬区的陕西省长武县的黑垆土及位于水蚀风蚀交错区的陕西省神木县六道沟流域的沙黄土为研究对象,对黄土塬区不同耕作覆盖措施对土壤理化性状(特别是水气传输性)和作物农艺性状的影响进行研究,主要测定了不同耕作覆盖下土壤水分、温度、容重、硬度、饱和导水率、导气率、相对气体扩散率、全氮、全磷、速效磷、株高、叶面积指数、产量等;同时对黄土高原水蚀风蚀交错区不同土地利用类型(撂荒地、柠条地、苜蓿地、裸地和农地)和不同退耕年限下土壤孔隙结构变化和水气传输性变化进行研究,主要测定土壤容重、总孔隙度、充气孔隙度(100cmH2O基质吸力)、饱和导水率、导气率和相对气体扩散率等。研究结果表明:(1)在黄土塬区的定位试验下,免耕处理降低了土壤容重,提高了土壤饱和导水率和4月下旬至10月上旬表层土壤含水量,使土壤硬度增加,造成土壤板结,降低了作物出苗期温度,降低了成熟期土壤全磷与速效磷含量,降低了株高、叶面积指数和产量。而地膜覆盖极显著增加了土壤容重(P0.01),显著降低了土壤饱和导水率(P0.05),降低了成熟期土壤有机质、全氮含量,有较为明显的保持和调节温度的作用,可缩小地温的昼夜变幅,此外不同类型的地膜覆盖均能极显著提高玉米株高和叶面积指数进而提高产量(P0.01)。秸秆覆盖对土壤容重和含水量的影响与耕作方式有关:翻耕条件下,秸秆覆盖增加了土壤容重;免耕条件下,降低了土壤容重且变化幅度均不显著。翻耕+秸秆覆盖土壤表层含水量最高;免耕+秸秆覆盖处理的土壤含水量最低。翻耕+秸秆覆盖可以有效起到抗旱作用,在降雨期间可降低峰值、延缓峰值到来,并在降雨后防止表层含水量迅速降低起到保水的作用;免耕+秸秆覆盖随着降雨的补给土壤含水量变化的幅度最大,对降雨的响应最为敏感,含水量随时间变化最快并最早达到峰值,降雨结束后含水量下降速度最快。但秸秆覆盖下土壤有机质含量、全氮含量、作物株高、叶面积指数和产量与未覆盖时相比均有增加,影响皆达到显著水平(P0.05),且均有降低地表温度的作用。秸秆覆盖、地膜覆盖均可有效减小免耕土壤硬度,但对传统翻耕表层土壤硬度无显著的影响。此外相同覆盖条件下传统耕作导气率均大于免耕,除CP1外不同覆盖类型均可增加传统翻耕土壤导气率和扩散率,而降低免耕导气率和扩散率。(2)水蚀风蚀交错区的定位试验表明,坡地土壤容重为苜蓿地农地撂荒地,总孔隙度为苜蓿地农地撂荒地,大孔隙(当量孔径φ≥30μm)孔隙度为撂荒地农地苜蓿地,小孔隙(当量孔径φ≤30μm)孔隙度为农地苜蓿地撂荒地。梯田土壤容重为苜蓿地裸地撂荒地柠条地农地,总孔隙度为苜蓿地裸地撂荒地柠条地农地,大孔隙(当量孔径φ≥30μm)孔隙度为农地撂荒地柠条地裸地苜蓿地,小孔隙(当量孔径φ≤30μm)孔隙度为裸地苜蓿地柠条地农地撂荒地。坡地、梯田苜蓿地土壤孔隙连通性、土壤导气率和相对气体扩散率均显著大于其他植被类型,土壤孔隙弯曲度显著小于其他植被类型;而农地土壤孔隙连通性和大孔隙连通性皆在所有土地利用方式中最小,土壤孔隙弯曲度最大;说明苜蓿地较农地改善了土壤结构和水气传输性。(3)水蚀风蚀交错区随着退耕年限的增加(12a、15a、41a)撂荒地土壤容重(ρb)增加,总孔隙度(f)降低,大孔隙(当量孔径φ≥30μm)孔隙度增加,小孔隙(当量孔径φ≤30μm)孔隙度降低,土壤饱和导水率(ks)、导气率(ka)和相对气体扩散率(Dp/D0)均增加;而苜蓿地土壤饱和导水率(ks)、导气率(ka)和相对气体扩散率(Dp/D0)均降低。此外,随着退耕年限的增加撂荒地土壤孔隙弯曲度增加,连通性减小,大孔隙的连通性增加;随着年限的增加苜蓿地各处理土壤孔隙弯曲度差异未达到显著水平,土壤孔隙连通性和大孔隙连通性均呈下降趋势。(4)黑垆土和沙黄土分别对应的土壤饱和导水率(ks)、导气率(ka)和相对气体扩散率(Dp/D0)之间的相互关系显示,ka与ks、(Dp/D0)与ks、ka与(Dp/D0)均呈显著线性正相关关系。
[Abstract]:In order to study the influence of different management measures on the transport of soil water and gas, the sand loess in Changwu County, Shaanxi Province, located in the Loess Tableland and the six ditu valley of Shenmu county, Shaanxi Province, located in the water erosion wind erosion crisscross area, was studied. The soil physical and chemical properties (especially water and gas transmission) were carried out by different tillage coverage measures in the loess tableland area. The soil moisture, temperature, bulk density, hardness, saturation conductivity, gas conductivity, relative gas diffusivity, total nitrogen, total phosphorus, available phosphorus, plant height, leaf area index, yield and so on, and the different land use types of the water erosion wind erosion ecotone of the Loess Plateau (abandoned land use) were measured. Soil pore structure change and water gas transmission change under different years of cultivated land, Caragana land, alfalfa land, bare land and farmland, and the main determination of soil bulk density, total porosity, inflatable porosity (100cmH2O matrix suction), saturated water conductivity, gas conductivity and phase to gas diffusivity. The results show: (1) in the Loess Tableland Area Under the test, no tillage treatment reduced soil bulk density, increased soil saturated water conductivity and water content in the surface soil from late April to early October, made soil hardness increase, cause soil consolidation, reduced the temperature of crop seedling stage, reduced total phosphorus and available phosphorus content in mature soil, reduced plant height, leaf area index and yield. Soil bulk density significantly increased soil bulk density (P0.01), significantly reduced soil saturated water conductivity (P0.05), reduced soil organic matter and total nitrogen content in mature soil, and had a more obvious retention and adjustment of temperature, which could reduce the diurnal variation of soil temperature. In addition, different types of film mulching could significantly increase the height of maize plant and leaf area index. The effect of straw mulching on soil bulk density and water content was related to the tillage method: straw mulching increased soil bulk density under the ploughing condition. Under no tillage, the soil bulk density was reduced and the change amplitude was not significant. The soil moisture content of the soil layer covered with straw and straw mulching was the highest, and the soil moisture content treated with no tillage + straw mulching was water content. The amount of ploughing and straw mulching can effectively resist drought. During rainfall, it can reduce the peak value, postpone the peak arrival, and prevent the rapid decrease of water content in the surface of the surface. The quickest change with time and the earliest peak value, the water content drops fastest after the end of the rain. But the soil organic matter content, total nitrogen content, plant height, leaf area index and yield are all increased compared with that of uncovered, and the effect of soil organic matter content, leaf area index and yield has reached significant level (P0.05), and the effect of reducing surface temperature. Straw mulching, land Film mulching can effectively reduce the hardness of no tillage soil, but have no significant influence on soil hardness of traditional tillage surface. In addition, under the same cover conditions, the traditional cultivation rate of traditional tillage is greater than that of no tillage. In addition to CP1, the different cover types can increase the gas conductivity and diffusion rate of traditional tillage soil, and reduce the air conductivity and diffusion rate of no tillage. (2) water erosion wind erosion. The location test of the wrong area shows that the soil bulk density of the slope land is the abandoned land of the alfalfa farmland, the total porosity is the abandoned land of the alfalfa farmland, the porosity is the abandoned land alfalfa and the porosity is the abandoned land of the alfalfa, the porosity is the abandoned land of the alfalfa. The soil bulk density of the terrace is the bare land of the alfalfa land. Caragana farmland, the total porosity is the land of Caragana korshinskii in the bare land of alfalfa, the porosity (equivalent pore diameter, or more than 30 u m) is the bare land alfalfa in the abandoned land Caragana, and the porosity is the abandoned land of the Caragana land in the bare land. The soil pore connectivity and the soil conductivity of the soil in the alfalfa land. The rate and relative gas diffusion rate were significantly greater than that of other vegetation types, and the soil porosity flexural degree was significantly smaller than that of other vegetation types, while the porosity connectivity and macropore connectivity were the smallest in all land use ways and the soil porosity was the largest, indicating that the soil structure and the water and gas transmission were improved in the alfalfa land. (3) The soil bulk density (P B) of the abandoned land increased (12a, 15a, 41a) increased, the total porosity (f) decreased, the porosity of the large pore (equivalent pore diameter or 30 u m) increased, and the porosity of the small pore (equivalent pore diameter < 30 m) decreased, the soil saturation and water conductivity (KS), the gas conductivity (KA) and the relative gas diffusivity (Dp/D0) increased. The soil saturated water conductivity (KS), gas conductivity (KA) and relative gas diffusivity (Dp/D0) decreased in alfalfa soil. In addition, the soil porosity flexural degree increased, connectivity decreased and the connectivity of macropores increased with the increase of cultivated land. The relationship between pore connectivity and macropore connectivity showed a downward trend. (4) the relationship between soil saturated water conductivity (KS), gas conductivity (KA) and relative gas diffusion rate (Dp/D0) showed that both Ka and KS, (Dp/D0) and KS, Ka and (Dp/D0) had a significant linear correlation.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S152

【参考文献】