【作者】 曾泽彬；

【导师】 朱雪梅； 朱波；

【作者基本信息】 四川农业大学 ， 土壤学， 2011， 硕士

【摘要】 研究不同施肥处理对川中丘陵区紫色土微生物活性及N20排放的影响,对建立川中丘陵区最佳施肥制度,提高肥料利用率,降低紫色土N20排放及准确估算紫色土农业生态系统中N20排放量具有重要的意义。本研究选取川中丘陵区小麦-玉米轮作制度下紫色土耕地,通过6种施肥处理即：猪厩肥(OM)、猪厩肥+氮磷钾肥(OMNPK)、秸秆+氮磷钾肥(RSDNPK)、氮磷钾肥(NPK)、氮肥(N)和不施肥(CK),研究了玉米生育期内(2010年5月至9月)土壤微生物的数量和生物量、土壤呼吸强度、代谢熵、土壤酶活性及N20排放通量。其结果如下：(1) OMNPK、OM、RSDNPK和NPK处理能显著提高玉米各生育期中土壤细菌、真菌、放线菌、氨氧化细菌、硝化细菌和反硝化细菌数量,其中,OMNPK处理对提高其土壤细菌、真菌、放线菌和氨氧化细菌数量的效果最显著,较CK提高了93.62%、98.71%、121.42%和275.64%；N处理对土壤氨氧化细菌、硝化细菌和反硝化细菌及真菌数量有一定程度提高,同时明显降低其细菌和放线菌数量,较CK降低了11.92%和36.61%。玉米整个生育期,不同施肥处理土壤微生物数量变化趋势基本一致,玉米拔节期是土壤硝化细菌数量最大值出现期,其余微生物数量达最大值则出现在玉米灌浆期。(2)整个玉米生育期,不同施肥处理土壤微生物量碳、氮变化趋势一致,均在玉米灌浆期达到最大值。OMNPK、OM、RSDNPK和NPK处理显著提高玉米各生育期中土壤微生物量碳、氮含量,其中以OMNPK处理最大,RSDNPK处理次之,N处理最小。(3)施肥明显提高玉米各生育期中土壤呼吸强度,其顺序依次为OMNPK >OM>RSDNPK>NPK>N>CK,不同施肥处理土壤呼吸强度最大值均出现在玉米灌浆期。施肥明显降低玉米各生育期中代谢熵,其顺序依次为CK>N>OM >RSDNPK>NPK>OMNPK,不同施肥处理代谢熵最大值均出现在玉米拔节期。(4)施肥显著提高玉米各生育期中土壤脲酶、碱性磷酸酶、转化酶、蛋白酶、硝酸还原酶、羟胺还原酶和亚硝酸还原酶活性,其中以OMNPK处理最显著,RSDNPK处理次之；施肥降低了土壤过氧化氢酶活性,其中以OM和OMNPK处理降幅最大,单施氮肥最小。玉米整个生育期,不同施肥处理土壤脲酶、碱性磷酸酶、羟胺还原酶和过氧化氢酶的活性最大值均出现在玉米灌浆期,土壤转化酶和硝酸还原酶活性均在玉米拔节期达最大值,而土壤蛋白酶和亚硝酸还原酶活性高峰则出现在玉米苗期。(5)施肥明显提高了玉米各生育期中土壤铵态氮和硝态氮含量,进而显著增加了玉米生育期土壤N2O排放通量及总量,其土壤N2O平均排放通量为40.86-156.43 ug.m-2.h-1,排放总量为0.46-1.75 kg.hm-2,占当季肥料施用量的0.91%-1.17%,其中以OM处理最大,RSDNPK处理最小。土壤铵态氮和硝态氮含量的变化趋势与土壤N2O排放通量变化趋势基本一致,这显示土壤铵态氮和硝态氮是玉米生育期土壤N2O排放的主要限制因子。(6)施肥能显著提高玉米产量,其中OMNPK和RSDNPK处理提高玉米产量明显优于NPK、OM、N和CK,其大小顺序为OMNPK>RSDNPK>NPK> OM>N>CK,较CK提高1843.54%、1841.19%、1660.43%、1506.59%和663.41%。更多还原

【Abstract】 Effects of fertilization on soil microbial activity and N2O emission of Purple Soil in Central Sichuan Hilly Areas were studied, which aimed to establish the best fertilization system in central Sichuan hilly area, improve fertilizer use efficiency, reduce the purple soil N2O emission and accurately assess the N2O emission in the purple soil agro-ecosystem.Six different treatments, including pig manure (OM), pig manure+N, P, K fertilizers(OMNPK), straw+N, P, K fertilizers (RSDNPK), and the treatment of N, P, K fertilizers (NPK), N fertilizer (N) and no fertilizers (CK), were applied to the purple soil of wheat- maize rotation cropland in central Sichuan hilly areas. Soil microbial quantity, soil microbial biomass, soil respiration intensity, metabolic quotient, soil enzyme activities and N2O emission at different maize growth stages (from May to September,2010) were studied. The main results were as follows:(1)The quantities of soil microbes (bacteria, fungus, ammonia-oxidizing bacteria,actinomycetes, nitrifying bacteria and denitrifying bacteria) were improved significantly by OMNPK, OM, RSDNPK and NPK treatments at different maize growth stages. OMNPK treatment had the best effect, and increased the quantities of bacteria, fungus, actinomycetes and ammonia-oxidizing bacteria by 93.62%,98.71%,121.42% and 275.64% respectively, compared with CK. The quantities of ammonia-oxidizing bacteria, nitrifying bacteria and denitrifying bacteria were increased at some extent, while the quantities of bacteria and actinomycetes were reduced by 11.92% and 36.61% compared with CK. The change of soil microbes quantity showed the same trendency in different treatments at the whole maize growth stage, the maxima of actinomycetes quantity were appeared in maize jointing stage, and the maxima of the other soil microbes quantity were appeared in maize filling stage.(2) In the whole maize growth stages, soil microbial biomass C and N showed the same chang trendency in all the treatments, and the maxima of soil microbial biomass C and N were all in the maize filling stage. OMNPK, OM, RSDNPK and NPK treatments significantly increased the soil microbial biomass C and N in maize growth stages, and the OMNPK treatment had the best effect, then followed by the RSDNPK treatment, while the N treatment had the minimun value.(3) Fertilization treatments significantly affected the soil respiration intensity, and the soil respiration intensity order was OMNPK>OM>RSDNPK> NPK>N>CK, the maxima of the soil respiration intensity were all in the maize filling stage, while all the treatments significantly decreased the soil metabolic quotient, the soil metabolic quotient order was CK>N>OM>RSDNPK> NPK>OMNPK, and the maxima of the soil metabolic quotient of all the treatments appeared in the maize jointing stage.(4) Fertilization treatments significantly increased the activities of the soil urease, alkaline phosphatase, invertase, protease, hydroxylamine reductase, nitrite reductase and nitrate reductase. The OMNPK had the best effects, followed by the RSDNPK. While all the treatments reduced the catalase activity, the best decreasing effects were the OM and OMNPK, while the N treatment reduced the catalase activity least. In all the maize growth stages, the maxima of soil urease, alkaline phosphatase, hydroxylamine reductase and catalase activities appeared in the maize filling stage,but the maxima of soil invertase and nitrate reductase activities appeared in the jointing stage, and the maxima of the soil protease and nitrite reductase appeared in the seedling stage.(5) Fertilization treatments significantly increased the soil ammonium nitrogen and nitrate nitrogen contents, and then increased the soil N2O emission flux and total contents in the maize growth stages as well, and the maximum ammonium nitrogen and nitrate nitrogen contents appeared in the OM, and the minimum apperared in the RSDNPK. In all the treatments, the average soil N2O emission fluxs were 40.86-156.43ug.m-2.h-1, and the average soil N2O emission total contents were 0.46-1.75 kg.hm-2, which were 0.91%-1.17% of the fertilizing amount of the current season. The soil ammonium nitrogen and nitrate nitrogen contents showed the same change tendengcy as the soil N2O emission flux, which indicated that soil ammonium nitrogen and nitrate nitrogen were the main limiting factors of the soil N2O emission in the maize growth stages in hilly areas of the central Sichuan.(6) Fertilization treatments significantly increased the maize yields. OMNPK and RSDNPK treatments both had higher yields than the NPK, OM, N and CK. And the order of the maize yields in all the treatments was OMNPK>RSDNPK>NPK>OM>N>CK. Compared with the CK,the maize yields of the OMNPK, RSDNPK, NPK, OM and N increased by 1843.54%, 1841.19%,1660.43%,1506.59% and 663.41% respectively.更多还原