【作者】 谢勇；

【导师】 王昌全；

【作者基本信息】 四川农业大学 ， 土壤学， 2009， 硕士

【摘要】 近年来,国家重视能源农业,各类农村沼气工程发展起来,农村能源问题得到有效解决,而产生的大量沼渣未能充分利用,造成资源严重浪费。大量研究涉及秸秆、绿肥、畜禽粪便等有机肥对土壤碳、氮的影响,而沼渣还田对不同种植模式下土壤碳、氮形态及其含量变化方面的研究未见报道。因此,在等氮、磷、钾条件下,以施用化肥为对照,采用大田试验,研究了施用沼渣对“玉米/大豆-小麦”间套作、“棉花-小麦”轮作、“水稻-油菜”轮作和果园4种不同种植模式土壤中不同碳、氮形态及其含量的影响;通过定位试验,研究了沼渣连续施用对“棉花-小麦”轮作田土壤碳、氮形态的剖面分布特征。主要研究结果如下:(1)不同种植模式施用沼渣均有利于总有机碳、易氧化有机碳、难氧化有机碳和腐殖酸态碳(FA+HA)的积累,较对照分别增加0.75～2.06g/kg、0.44～1.40g/kg、0.14～1.16g/kg和0.85～2.62g/kg,其中果园最为明显。果园土壤中总有机碳、易氧化有机碳和腐殖酸态碳(FA+HA)含量尤以后两者较其它种植模式大,增幅分别为28.50%、50.83%和61.80%。从绝对含量上看易氧化有机碳和难氧化有机碳均与总有机碳的变化同步。“水稻-油菜”轮作土壤中难氧化有机碳较对照的增量和增幅均最大。(2)“玉米/大豆-小麦”间套作、“棉花-小麦”轮作、“水稻-油菜”轮作和果园4种种植模式施用沼渣,土壤微生物碳、微生物氮含量均较对照增加,增量介于6.71～149.54mg/kg之间。从土壤微生物碳来看,果园较对照增幅最大,其值为149.54%,其次是“水稻-油菜”轮作,而“玉米/大豆-小麦”间套作增幅最小,仪为6.71%。从土壤微生物氮来看,“棉花-小麦”轮作较对照增幅最大,为91.35%,其次是果园,“玉米/大豆-小麦”间套作与“水稻-油菜”轮作较对照的增幅均介于30%～37%之间。(3)“玉米/大豆-小麦”间套作、“棉花-小麦”轮作、“水稻-油菜”轮作和果园4种种植模式施用沼渣后,土壤有机态氮组分中酸解性氮含量均大于非酸解氮含量,酸解性氮含量均较对照增加,增幅介于10.03%～30.89%之间,非酸解氮含量均较对照减少,减少幅度介于2.53%～40.32%之间。在酸解性氮中,各种模式的土壤氨基酸态氮含量均较高,介于201.3～231.5mg/kg之间,各种模式的土壤氨基糖态氮含量均为最低,其值介于62.1-93.6mg/kg之间,酸解未知氮含量仅“水稻.油菜”轮作较对照增加,其余种植模式较对照均减少。施用沼渣后,土壤氨基酸态氮含量以果园较对照增幅最大,增幅达84.00%,“棉花-小麦”轮作较对照增幅最小,增幅仅15.67%;土壤氨态氮含量以“棉花-小麦”轮作较对照增幅最大,增幅达65.60%,果园对照增幅最小,增幅仅18.70%;土壤氨基糖态氮含量以果园较对照增幅最大,增幅达64.07%,“水稻-油菜”轮作对照增幅最小,增幅仅16.02%。(4)沼渣施用使土壤中总有机碳、易氧化有机碳和难氧化有机碳含量均随沼渣连续施用年限的延长而增加;对于不同的沼渣连续施用年限,其各层的增幅变化趋势不一致,沼渣连续施用3年使0～30cm土壤中总有机碳、易氧化有机碳和难氧化有机碳含量均极显著增加。(5)土壤微生物碳、氮含量整体上随沼渣连续施用年限的延长而增加,在0～50cm剖面分布上,施用沼渣1年0～30cm土壤微生物碳、氮变化较大,能显著提高30～40cm土层土壤微生物碳和微生物氮的含量,沼渣连续施用5年时对40～50cm土层微生物碳、氮无明显影响。施用沼渣对0～20cm土层微生物碳含量和10～30cm土层微生物氮含量的影响均为随着连续施用年限的延长而增幅下降;30～40cm土层微生物碳含量的影响为随着连续施用年限的延长其增幅递增;20～30cm土层微生物碳和0～10cm、30～40cm土层微生物氮含量的影响均为随着连续施用年限的延长增幅先增加后下降。耕层土壤微生物碳/微生物氮施用沼渣1年较习惯耕作增加,沼渣连续施用3年后呈减少趋势。微生物碳/有机碳与微生物氮/全氮不同施用年限在剖面上的变化趋势与微生物碳的变化趋势一致。(6)施用沼渣后,土壤中积累的氮素以氨基酸态氮、酸解未知态氮为主;沼渣不同施用年限之间相比,除个别层次外,土壤酸解氮中氨基酸态氮、氨基糖态氮及氨态氮占全氮的比例顺序依次为:施用沼渣5年＞施用沼渣3年＞施用沼渣1年＞习惯性耕作;土壤全氮及酸解性有机总氮、氨基酸态氮、氨态氮和氨基糖态氮含量均随土层深度的增加而降低,而酸解未知态氮的含量先升后降;对于相同土层,土壤酸解氮中各组分绝对含量和相对含量的大小排列顺序均为:酸解未知态氮＞氨基酸态氮＞氨态氮＞氨基糖态氮。更多还原

【Abstract】 The national payed serious attention to energy agriculture,the various types of biogas projects in rural have been developed,and rural energy issues had been effectively resolved,but a lot of biogas generated had not been fully utilized,leading to the serious waste of resources in recent years.There were a lot of studies involved in the affection taken to the soil C and N from the organic fertilizer which contened the straw,green manure,and livestock and poultry manure.Wheras there was no report about the research that the affection to the change of soil C and N content from the application on biogas residue in different cropping patterns.As a result,in the same content of nitrogen, phosphorus and potassium under the conditions to application of fertilizer as a control, useing field experiments to study the effects of soil carbon and nitrogen content in the form of impact that use biogas residue in "corn/soybean-wheat" intercropping,"Cotton-wheat" rotation,"Rice-Rape" rotation and four kinds of different orchards planted patterns; through the experiment to study that continuous use of biogas for the "cotton - wheat" rotation fields,soil C,N distribution patterns of the profiles.The main results were as follows:(1) All application of biogas in different cropping pattems were conducive to accumulate TOC,easily oxidized organic carbon,hardly carbon and humic acid oxidation (FA+HA),and increased 0.75～2.06g/kg,0.44～1.40g/kg,0.14～1.16g/kg respectively compared to control.Besides,the changing of orchards was significant of all.In orchards,TOC,easily oxidized organic carbon and humic acid oxidation(FA + HA) were obviously higher than other cropping patterns,especially to the latter two.And each the increase amplitude was 28.50%,50.83%and 61.80%.Absolute terms from the content, easily oxidized organic carbon,hardly carbon,humic acid oxidation(FA + HA) and organic carbon were synchronous changed with total organic carbon.In "Rice-rape" rotation,increment and increase amplitude of difficult oxidized organic carbon were both reached to the maximum compared to the control.(2) "Corn/Soybean-Wheat" intercropping,"Cotton-wheat" rotation,"Rice-rape" rotation and orchards,four kinds of planting mode were dealed with the application of biogas residue,the content of soil microbial carbon and nitrogen were more than that in control micro-organisms,increments between 6.71～149.54mg/kg.From the microbial carbon Point of view,compared to the control,the largest increase was in the orchard,and its figure was 149.54%,followed by the "rice-raPes" rotation,wheras the "corn/soybean-wheat" intercropping was the smallest increment,only 6.71%.From the microbial nitrogen point of view,compared to the control,the largest increase was in the "Cotton- wheat",and the increasing number was 91.35%,followed by the orchards. Compared to the control,the increments of the "corn/soybean - wheat" intercropping and "rice-rape" were both between 30%～37%.(3) "Corn/Soybean-Wheat" intercropping,"Cotton-wheat" rotation,"Rice-rape" rotation and orchards,four kinds of planting mode were dealed with the application of biogas residue.Then the content of the acid solution nitrogen in the soil organic nitrogen fraction was higher than the nitrogen content of non-acid solution.Compared with those in the control of the nitrogen content,the nitrogen content in the acid solution increased by 10.03%～30.89%,while the nitrogen content in the non-acid solution reduced about 2.53%～40.32%.The nitrogen in the acid solution,the various patterns of amino acid nitrogen content of the soil were high ranging between 201.3～231.5mg/kg,and various patterns of amino sugar N content in soil was lowest ranging from 62.1 to 93.6mg/kg. Compared with the control,the nitrogen content of the unknown acid solution alone of "Rice-rape" rotation increased,while the content of the other kinds of planting mode reduced.After the application of biogas,soil nitrogen content of amino acids of orchard increased the most by 84.00%.Comparing to the control,and the content of "Cotton-wheat" rotation increased the least by only 15.67%;The ammonia nitrogen content of soil of "cotton-wheat" rotation increased the largest over the control by 65.60%, while the smallest increase was orchard only 18.70%;The soil amino sugar N content in the orchard increased the largest to the control about 64.07%,while "Rice-rape" rotation was the smallest increase to control by only 16.02%.(4) Application of biogas residue promoted the accumulation of soil organic carbon, readily and hardly to be oxidized organic carbon with the extension of biogas residue use time.However,the increasing range of each layer was inconsistent.The content of total organic carbon,readily oxidized carbon and hardly oxiddized carbon were increased extremely signifcantly in the 0～30cm soil layer after 3 years of biogas residue’s continous application.(5) The soil MBC and MBN increased with time limit that the biogas residue was applied,and in the 0～50cm profile,the content of soil MBC and MBN decreased with the depth increased under every treatment.When the biogas residue was applied from 1 to 3 year, in the 0～30 cm Profile,soil MBC and MBN changed markedly,in the 30～40cm Profile, the soil MBC and MBN became stable and when the biogas residue was applied five years, the impaction was,more obvious,but there was no effect in the 40～50cm profile.In the 0～30cm profile,the amplification of the soil microbial biomass C descent with the increased time limit:When the biogas residue applied one year,soil MBC increased 31.73%than the accustomed farming,in three years,it increased 21.63%compared to one year,and in five years,it increased 13.54%compared to three years,in the 0～10 cm profile, the change tendency of MBN was coincident with MBC,in the 10～30cm layer,the amplification of MBN decreased with the tine went on.And the trend of MBC/SOC and MBN/TN were the same with MBC.When biogas residue was applied just one year, MBC/MBN increased than accustomed farming in the topsoil,but they reduced when biogas residue was applied three years.So we can see for the rotation pattern "cotton-wheat", if the biogas residue was applying three years continued,it would improve soil fertility effectually in the 0～30cm profile.(6) After the application of biogas,accumulation of soil nitrogen to amino nitrogen and unknown acidolysis N;biogas compared between different application period,in addition to the individual level,the soil nitrogen in the amino acid-N,amino sugar-N and ammoniacal-N in the proportion of total N order as follows:5-year application of biogas＞3-year application of biogas＞1-year application of biogas＞customary farming;total soil nitrogen and organic acid solution of total nitrogen,amino nitrogen,ammonia nitrogen and amino sugar-N content increased with soil depth reduced,and the acid solution of unknown concentration of the nitrogen first and then decreased;for the same soil layer, acid soil nitrogen content of each component and the relative content of the absolute size of the order were:unknown acidolysis N＞amino acid N＞ammoniacal N＞amino sugar N.更多还原