【作者】 邱莉萍；

【导师】 王益权；

【作者基本信息】 西北农林科技大学 ， 土壤学， 2004， 硕士

【摘要】 土壤酶是影响土壤生产力和作物产量主要因子,反映着土壤管理的作用与效果,参与了土壤的发生和发育,加速腐殖质的合成与分解,参与有效肥力形成等诸多过程。酶学方法和酶的活性可以广泛地应用于评价土壤肥力,鉴别土壤熟化度,同时,还用它来评价各种农业措施和培肥的效果。研究土壤酶的动力学、热力学特征对于描述土壤中生化反应的进程和土壤酶的作用机理有重要意义。本研究以长期定位试验土壤为材料,研究在培肥过程中土壤理化性质和土壤酶的演替规律,探讨土壤酶的动力、热力学特征,进一步探讨土壤酶作为肥力指标的灵敏性,为合理地进行土壤管理、使土壤生产力得到持续发展提供科学依据。获得以下主要结论:1. 长期培肥改善了表层土壤酶活性和主要养分含量。培肥效果依次为有机无机肥配施>化肥>无肥。由相关分析、通径分析和主成分分析均表明土壤脲酶与碱性磷酸酶可以作为表征土壤肥力的灵敏指标。2. 长期培肥对土壤剖面酶活性分布影响很大。研究发现在 40cm 土壤剖面内,土壤酶活性有了明显地提高;除多酚氧化酶外,脲酶、碱性磷酸酶、蔗糖酶均随剖面加深活性减小。各土层脲酶、碱性磷酸酶、蔗糖酶活性与相应土层有机质含量有极显著相关性。培肥能够使较深土层土壤质量性状得到了改善,对于干旱地区农业有着更为重要的现实意义。3. 培肥作用增加了土壤团聚体、特征微团聚体的数量,显著地改善了土壤结构。培肥土壤团聚体 MWD、特征微团聚体 C/F0.01较无肥对照土壤有显著增加。4. 长期培肥增强了土壤化学、生物性质的“微域”变异性。相同培肥措施下土壤主要养分含量和酶活性绝大情况下随土壤团聚体直径的增大而减小。除厩肥处理土壤碱性磷酸酶和蔗糖酶外,其它各培肥土壤的养分含量和酶活性均在<0.01mm 级别特征微团聚体中含量高、活性大。相同级别团聚体和特征微团聚体中,养分含量和酶活性在不同培肥土壤间均表现出 BM>MS>CF>CK 规律性。充分地显示着土壤性质在不同空间尺度下、不同管理措施下变异的复杂性和多样性。5. 土壤脲酶和碱性磷酸酶的活性均随酶促反应时间的延长而逐渐趋于一个稳定值,各个时间段内酶活性均为施肥处理高于无肥处理;两者的酶促反应初速度(V0)均随温度、底物浓度的增加而增加,且至一定温度和底物浓度时,反应的初速度不再增加;不同培肥措施对土壤酶促反应初速度的影响均为:BM>MS>CF>CK。6. 动力学、热力学参数从不同角度表征了酶促反应机理在各种肥力土壤间的差异性。培肥提高了 Vmax、Vmax/Km、k 值,降低了 Ea、△G、△H 和△S 值,说明培肥<WP=6>能够改善酶的能量状态,减小活化自由能,促进酶促反应快速进行,从而加快了土壤物质循环过程。用动力学和热力学参数清楚地表征了土壤培肥的作用与效果。更多还原

【Abstract】 As a major factor, soil enzymes not only influence soil productivity and crop yield,but also reflect the function and effect of soil management. Soil enzymes participate in soilformation and development and accelerate the compounding and discomposing process ofsoil humus, besides, soil enzymes play a great role in such processes as the formation ofsoil fertility. The study on the soil enzymes and enzymatic activity have been popularlyused to assess soil fertility, distinguish the development mellow degree of soil, and oftenbeen used to evaluate the effects of different agricultural measurements and fertilization.Furthermore, the study on the dynamic and thermodynamic characteristics of soil enzymeshelps us to understand processes of bio-chemical reactions and mechanisms that enzymesplayed.Based on the long-term fixed experimental soil, this paper studied the successionorderliness of soil physic-chemic properties and enzyme in fertilizing process. In addition,the enzymes’ dynamic and thermodynamic characteristics were discussed. Moreover, thesensitivity of soil enzymes used to indicate soil fertility was also researched so as to find anew way in reasonable management of soil resource, provide scientific evidence to makesoil fertility develop sustainly. The main results are as follows:1. Long-term fertilization improved soil enzymatic activities and soil fertility intopsoil. The effects of fertilizations on improving soil fertility were in the order of Manurecombined with chemical fertilizers>Chemical fertilizer>Control. The results of correlation,path and principal component analysis showed that soil urease and alkaline phosphatasecould be used as sensitive indexes to indicate soil fertility.2. Long-term fertilization exerts strong effects on the distribution of soil enzymaticactivities in soil profile. In 0-40cm soil enzymatic activities have enhanced distinctly;activities of urease, alkaline phosphatase, and invertase are reduced with the increment ofsoil depth except polyphenol oxidase. Furthermore, activities of soil enzymes in each soildepth correlates with soil organic matter contents in corresponding depth. Fertilization canimprove soil quality in deeper soil layers, it has more important practical significance inagriculture of arid area.3. Fertilization augmented the amount of aggregate and characterizedmicro-aggregate in soils, improved the quality of soil structure significantly. The MWD ofsoil aggregate and C/F0.01 of characterized micro-aggregate in fertilization treatments were<WP=8>higher than in control.4. Long-term fertilization increased the variance of soil chemical and biologicalproperties in soil micro-environments. In the same fertilization treatment, the mainnutrients content and enzymatic activities decreased with the increasing of diameter of soilaggregate in most cases. Besides, the indexes above presented the highest content oractivity in the characterized micro-aggregate less than 0.01 mm in all the treatments exceptthe alkaline phosphatase and invertase in manure treatment. The distribution of the mainnutrients content and soil enzymatic activities presented as the order of BM>MS>CF>CKin the same aggregate and characterized micro-aggregate. Under different spatial scalesand managing treatments, soil properties showed the complexity and diversity of variance.5. Activities of soil urease and alkaline phosphatase increased and reached to aconstant with prolonging of incubation time. Moreover, activities of soil urease andalkaline phosphatase were always higher in fertilization treatments than in controltreatment. The V0 of soil urease and alkaline phosphatase increased with the rising oftemperature and reactant concentrations until they reached a certain value. The V0 ofdifferent fertilizations showed the same order of BM>MS>CF>CK.6. The dynamic and thermodynamic parameters could show the difference of suchreactions’ mechanisms in each tested soil in various aspects. the Vmax, Vmax/Km and kincrea更多还原