【作者】 薛晓辉；

【导师】 郝明德；

【作者基本信息】 中国科学院研究生院（教育部水土保持与生态环境研究中心） ， 土壤学， 2010， 博士

【摘要】 施肥可以增加土壤肥力和提高作物产量,但过量施肥加剧了农田的氮淋溶和温室气体排放,导致了资源浪费和环境污染。本研究在典型的旱作农业区以长武农业生态试验站的长期定位试验为基础,研究了长期施肥对小麦产量、氮淋溶、N20排放、CO2排放以及土壤肥力的影响。1.施肥能显著提高小麦的产量。2006～2009年不施肥处理小麦产量最低,平均为1345kghm-2。施用N肥后平均产量为1594 kg hm-2,增加18.55%。NP配施时小麦产量大幅度增加,为3778kghm-2,是单施氮的2.37倍。施用有机肥能大幅增加小麦产量,单施M时平均产量为3884kghm-2,是不施肥的2.88倍。NPM配施时平均产量最高,可达4438kghm-2,是单施M的1.14倍。施肥能增加小麦的株高、穗长、小穗数和穗粒数,其中以NP配施和NPM配施时达到显著水平。单施N和单施M对株高、穗长、穗粒数、穗数和千粒重的影响不显著。不施肥时小麦植株吸氮量和吸钾量最低,2006～2009年均值分别为30.93kghm-2和34.79kghm-2。施肥后植株吸氮量和吸钾量增加,NPM配施时最高,分别可达152.55kghm-2和111.22kghm-2,是不施肥的4.93倍和3.20倍；单施N时植株吸磷量最低,仅3.99kghm-2,NPM配施最高,可达14.62kghm-2。不同肥料施用条件下氮肥利用率以NP配施时最高,可达61.81%,而单施N时最低,仅15.17%；磷肥利用率以NP配施最高,平均值为21.54%,单施M和NPM配施较低,分别为4.94%和4.57%。2.长期NPM配施后土壤养分增幅最高,有机质、全氮、全磷、有效磷和有效钾含量分别增加81.88%、115.97%、45.52%、1810.56%和242.85%。不施肥时有机质、全氮、全磷和有效磷含量增加幅度最低,仅10.02%、33.84%、-2.87%、-49.44%,NP配施时有效钾含量增加幅度最低,仅-1.56%。3.过量施用氮肥是造成硝态氮淋溶的主要因素。单施氮肥土壤硝态氮淋溶最为剧烈,不仅在60～180 cm土层出现累积层,而且部分硝态氮进入3m以下并在320 cm处形成累积峰,0～400 cm土层残留量最高可达1498.68 kg hm-2；NPM配施土壤剖面出现20-160 cm和160～320 cm两个累积区；NP配施时土壤剖面虽然也形成2个累积区,但硝态氮累积峰低于单施N和NPM配施；不施肥和单施M土壤深层均无硝态氮累积现象,且不施肥土壤硝态氮残留量最低,为61.34kghm-2。土壤铵态氮在土壤剖面的分布呈不规则的波动,其值大部分均在10.00～20.00 mgkg-1之内,不同肥料施用条件下0～400 cm土层残留量在650.85～989.73kghm-2之间。不同量的氮、磷肥配施条件下,1999至2007年土壤硝态氮向深层移动100 cm以上,无氮和低氮肥施用的土壤硝态氮主要集中在0-160 cm土层；过量施用氮肥土壤硝态氮分别在120～140 cm和240～260 cm附近形成累积峰；单施N肥量等于或大于90kghm-2 a-1时,硝态氮在80～100 cm土层出现累积峰,且部分硝态氮进入300 cm以下土壤,0～300 cm土层硝态氮残留量可达1500.18kghm-2。与NP配施相比,单施氮肥将导致更多的硝态氮进入土壤深层,且硝态氮残留量随着施氮量增加而显著增加。磷肥在不施氮和低氮肥用量条件下对土壤硝态氮残留量无影响,当施N量增加到90kghm-2或更高,硝态氮残留量将随着施磷量增加而减小施用NPM肥23年后硝态氮在小麦地土壤剖面出现2个累积层,分别在20～100cm和140～320 cm处,而苜蓿地硝态氮主要分布在0～60 cm土层,仅在200～300 cm土层处出现少量累积,土壤总残留量比小麦连作地减少了588.06kghm-2。4.不同肥料施用条件下土壤N2O排放通量在0.32～78.66μg N2O-N m-2h-1之间。年平均N2O排放通量以不施肥时最低,NPM配施时最高。单施N、NP配施和NPM配施时小麦萌芽期和出苗期N2O排放通量明显增加,其排放总量约占全年总排放量的25～30%。不施肥时土壤的N2O年排放总量为0.21kgN2O-N hm-2,单施M后N20年排放总量没有增加。单施N时土壤的N2O年排放总量显著增加,为0.34kg N2O-N hm-2,比不施肥增加了64%。NP配施时土壤的N2O年排放总量比单施N时略有降低,为0.33kgN2O-N hm-2,比不施肥增加了60%。NPM配施时土壤N2O年排放总量最高,可达0.37kgN2O-N hm-2,比不施肥增加了80%。5.不同肥料施用条件下土壤CO2排放通量在0.96-117.94 mg CO2-C m-2 h-1之间,不施肥土壤CO2年均排放通量最低,施用NPM时最高。小麦返青期和休闲期CO2排放通量较高,而越冬期最低。不施肥土壤CO2年排放总量为1391kgCO2-C hm-2,施用氮肥后增加至1464kgCO2-C hm-2,增加了5.25%。NP配施时土壤CO2的年排放总量显著增加,比不施肥增加了36.93%。单施M和NPM配施土壤CO2的年排放总量分别为2301kgCO2-Chm-2和2211lgCO2-C hm-2,比不施肥处理分别增加了53.64%和46.89%。此外,土壤CO2排放通量与气温以及0 cm、5 cm、10 cm、15 cm、20 cm、40 cm地温均呈线性显著相关。6.施肥加剧了作物对土壤深层水分的吸收利用,不同肥料施用条件下土壤干燥化一般出现在100～260 cm土层。不施肥时土壤100～260 cm土层含水量最高,2006～2009年平均为16.29%；NPM配施时最低,为9.99%；不同量的氮肥和磷肥施用条件下,100～260 cm深度出现土壤干燥化现象,播前0～300 cm土层贮水量差异在-136.5～5.4mm之间。更多还原

【Abstract】 Fertilization can increase soil fertility and crop yield, but excessive fertilization can enhance nitrate leaching and the emissions of greenhouse gases in the cropland, leading to waste of resources and environmental pollution. Based on the long-term fertilization experiment at the Changwu Agro-ecological experimental station in the typical dry-farming area, the objective of this work was to study the effect of fertilization on wheat yield, nitrate leaching, N2O emission, CO2 emission and soil fertility.1. Fertilization can increase the wheat yield significantly. The average yield of wheat was only 1345 kg hm-2 in unfertilized plot from 2006 to 2009, which reached to 1594 kg hm"2 and increased by 18.55% after single application of N fertilizer. The wheat yield was up to 3778 kg hm"2 and 2.37 times as high as that in N treatment when N and P fertilizer were applied together. Appling organic manure can increase more crop yield. The wheat yield of M plot was 3884 kg hm-2 and 2.88 times as high as that in unfertilized plot. When N fertilizer, P fertilizer and manure were applied in combination, the wheat yield was highest and up to 4438 kg hm-2, and 1.14 times as high as that in M treatment.Fertilization can increase height, ear length, spikelet number and grain per spike of winter wheat. The differences of height, ear length, spikelet number and grain per spike of winter wheat were significant in NP or NPM treatments compared with unfertilized plot, but Single application of N or M did not significantly affect height, ear length, grain per spike and 1000-grain weight of winter wheat.N and K uptake rates by wheat were lowest in unfertilized soil, and the average values were 30.93 kg hm"2 and 34.79 kg hm-2 from 2006 to 2009, respectively. N and K uptake rates by wheat increased after fertilization, N uptake rate were the highest (152.55 kg hm-2) in NPM treatment, which was 3.93 times higher than that in unfertilized plot. K uptake rate was the highest (111.22 kg hm-2) in NPM treatment, which was 2.20 times higher than that in unfertilized plot. P uptake rate was the highest (14.62 kg hm-2) when N, P and M were applied in combination, which was the lowest (only 3.99 kg hm-2) in N treatment. N recovery rate was the highest and up to 61.81% in NP plot under different fertilizer application conditions, and it was the lowest (15.17%) in N treatment. The highest value of P recovery rate was found in NP treatment, the average of which was 21.54% from 2006 to 2009. P recovery rates in M and NPM treatments were 4.94% and 4.57%, respectively.2. The increased rate of soil nutrition was the highest after the long-term combined application of N, P and M, and the concentrations of organic matter, total N, total P, available P and available K were increased by 81.88%,115.97%,45.52%,1810.56% and 242.85%, respectively. The increased rate of organic matter, total N, total P and available P were the lowest and increased by 10.02%,33.84%,-2.87% and-49.44% in unfertilized plot, and the increased rate of available K was only-1.56%.3. Excessive N fertilizer application was a main factor for nitrate leaching. NO3--N leached sharply into deep soil in N treatment. NO3--N was not only accumulated in 60～180 cm soil layer, but it also leached below 3 m depth and formed an accumulation peak near 320 cm depth in soil. Residual NO3--N amount was the highest (1498.68 kg hm-2) in 0～400 cm soil layer. NO3--N was accumulated in 20～160 cm soil layer and 160～320 soil layer in the vertical soil profile when N, P and M were applied in combination. NO3--N formed two accumulation zones in the vertical soil profile in NP treatment, but the highest value of NO3--N accumulation peaks were lower than that in N and NPM treatments. NO3--N accumulation were not found in deep soil in unfertilized and M plots, and residual NO3--N amount was the lowest (61.34 kg hm-2) in 0～400 cm soil layer in unfertilized plot. NH4+-N changed irregularly in the vertical soil profiles, the concentration range of which was 10.00 mg kg-1 to 20.00 mg kg-1, and residual amount of NH4+-N in 0～400 cm soil layer was from 650.85 kg hm-2 to 989.73 kg hm-2 under different fertilizer application conditions.From 1999 to 2007, the moving distance of NO3--N was over 100 cm from topsoil to subsoil under different N and P fertilizer application conditions. NO3--N was concentrated mainly in 0～160 cm soil layer under no and low N application conditions in the vertical soil profiles. However, NO3--N accumulation peaks were found in 120～140 cm and 240-260 cm soil layers under excessive N application conditions. When the rate of N single application was 90 kg N hm-2 or more per year, NO3--N was accumulated in 80～100 cm soil layer, and part of which had leached into subsoil below 300 cm depth, and residual NO3--N amount was up to 1500.18 kg hm-2 in 0～300 cm soil layer. Applying N alone easily led to NO3--N leaching compared with N and P combined application, and residual NO3--N amount increased significantly with increasing N application rate. There was no effect of P fertilizer on NO3--N leaching at no or low N level. When annual N application rate was increased to 90 kg hm-2 or more, residual NO3--N would decrease with increasing P application rate.There were two accumulation zones of NO3--N in the vertical soil profile after 23-year NPM application under continuous wheat cropping, one at 20～100 cm depth and the other at 140～320 cm depth. However, NO3--N was concentrated mainly in 0～60 cm soil layer under continuous alfalfa cropping, and accumulated slightly in 200～300 cm soil layer. Residual NO3--N amount in alfalfa field was 588.06 kg hm-2 less than that in continuous wheat cropping.4. The fluxes of N2O emission were 0.31～78.66μg N2O-N m-2 h-1 under different fertilizer application conditions. The average flux of N2O emission was the lowest in unfertilized plot and highest in NPM treatment per year. N2O emission fluxes of germination and seeding growth stages increased in N, NP and NPM treatments, and total N2O emission amounts of germination and seeding growth stages were 25～30% of total N2O emission amount in the whole growth year.Total amount of N2O emission was 0.21 kg N2O-N hm-2 in unfertilized soil per year, which did not increase after M application alone. However, Annual amount of N2O emission increased significantly when N fertilizer was applied alone, which was 64% higher than that in unfertilized plot, and the value was up to 0.34 kg N2O-N hm-2. Annual amount of N2O emission in NP treatment was lower than that in N treatment, which was 0.33 kg N2O-N hm-2 and increased by 60% compared with annual amount of N2O emission in unfertilized plot. Annual amount of N2O emission was the highest in NPM treatment and up to 0.37 kg N2O-N hm-2, which was 80% higher than that in unfertilized plot.5. The fluxes of CO2 emission were 0.96～117.94 mg CO2-C m-2 h-1 under different fertilizer application conditions. The annual average flux of CO2 emission was the lowest in unfertilized plot and highest in NPM treatment. The fluxes of CO2 emission in reviving and fallow stages were higher than other growth stages, and the lowest in over-wintering stage.Total amount of CO2 emission was 1391 kg CO2-C hm-2 in unfertilized plot per year, which was up to 1464 kg CO2-C hm-2 and increased by 5.25% after N fertilizer application alone. Annual amount of CO2 emission increased significantly when N and P fertilizers were applied in combination, which was 36.93% higher than that in unfertilized plot. Annual amounts of CO2 emission in M and NPM treatments were 2301 kg CO2-C hm-2 and 2211 kg CO2-C hm-2, which were 53.64% and 46.89% higher than that in unfertilized plot, respectively. In addication, CO2 emission flux was significantly linear correlated with air temperature and ground temperatures of 0 cm、5 cm、10 cm、15 cm、20 cm、40 cm soil lavers.6. Fertilization enhanced the water absorption and utilization of deep soil, and the desiccation of deep soil was found in the 100～260 cm soil layer under different fertilizer application conditions. The water content of soil was the highest in the 100～260 cm soil layer in unfertilized plot, and the average value was 16.29% from 2006 to 2009. The water content of soil was the lowest in the 100～260 cm soil layer in NPM treatment, and the average value was 9.99%. The desiccation of deep soil was found in the 100～260 cm soil layer under the condition of different N and P fertilizer application rates. The differences of moisture storage ranged from-136.5 mm to 5.4 mm in 0～300 soil layer before sowing.更多还原