【作者】 刘慧颖；

【导师】 韩晓日；

【作者基本信息】 沈阳农业大学 ， 植物营养学， 2013， 博士

【摘要】 本研究以大凌河地区玉米田为研究对象,以有效减少不合理施肥对水体、土壤、温室气体排放等农业面源污染为目标,应用田间原位渗漏计法、室内土柱淋溶模拟、静态暗箱-气相色谱法等研究方法,利用现实可行氮肥施入方式,开展稳产高产下3年定位试验的培肥地力、产量品质、温室气体排放和氮素利用监测并采用戒上型隶属函数确定评价指标的隶属度值,采用相关分析法确定权重系数,采用指数和法对不同氮肥施入方式进行定量评价研究。试验结果如下：1.在凌海地区自然降水条件下,不同氮肥施入方式不会在短期内造成氮素淋失；模拟条件下,土壤速效氮的淋溶量随施肥量的增加而增加；土壤源硝态氮淋失过程相对缓慢,肥料源硝态氮的淋失集中在3-8次,占总淋失率的86.7%,硝态氮是氮素淋溶的主要形态；秸秆还田明显降低了120cm土层内的土壤含水量。2.外援氮肥施入干扰了土壤速效氮的分布,浅层土壤含量变化大于底层土壤,并有表聚现象；土壤NO3—N、NH4—N随施氮量增加而增加；秸秆还田在生育前期因腐熟消耗一些氮源,但后期土壤可自我缓冲恢复,同时土壤硝态氮的固持能力增加,阻止N03-N向地下迁移,减少对地下水污染的危险；缓控释肥料的使用使养分释放的高峰期持续了30天,土壤NH4-N累积含量比农民习惯施肥增加了17.5%。3年定位试验,除土壤pH外,全量氮磷钾、速效氮磷钾及土壤有机质含量都较试验之初有所降低。缓控释肥处理可以提高土壤有机质、全量和速效氮含量；秸秆还田处理可有效提高全量和速效钾含量。缓控释肥处理土壤综合养分指数最高,达到83.5,培肥土壤的作用好于秸秆还田处理。3.秸秆还田和缓控释肥料后期叶片叶绿素含量高,有利于光合作用及其产物向籽实转移；随生育期推进,茎、叶、穗部含水量呈现下降趋势,缓控释肥料籽实的干物质含量最高；外援氮肥施入使玉米根茎叶和籽实全氮含量有所增加；处理间产量差异显著性随着试验年限增加而增强；缓控释肥处理与秸秆还田处理3年平均产量比习惯施肥增加3.3%和2.77%；施用缓控释肥年均氮肥农学利用率、氮收获指数、籽粒氮积累量都高于秸秆还田处理。植株总氮累积量、肥料利用率则是秸秆还田处理表现好,但其氮收获指数低,表明其吸收利用的氮素较少被生殖器官吸收。4.土壤中养分的变化影响了N20-N排放通量的变化,施肥量与N20排放总量的相关系数为0.98。秸秆还田和施用缓控释肥增加了N20排放。缓控释肥料处理N20-N排放通量前期受肥料缓慢释放的影响,后期受温度影响多些；随着试验年限增加,N2O-N季节排放系数受产量影响降低,而受施肥量的影响在逐年增加。因此不同氮肥施入方式对N20季节排放的影响需要通过多年定位来准确把握,并要适当考虑植株生长过程中N20的排放。肥料的使用增加了N2O排放。在纯化肥的氮肥施入方式下,随着施肥量的增加N2O排放增加。在非单纯化肥氮肥施入方式下,秸秆还田的方式增加了N2O排放,肥料的缓慢释放也导致N20排放量增加。5.缓控释肥料对氮素的缓控释作用导致其土壤的表观残留率是同施氮量普通化肥处理的1.4倍,是秸秆还田处理的1.3倍,而表观损失率远低于秸秆还田处理近2/3；考虑了产量、环境、培肥、资源效应等诸多因素在内的评价综合指标法对不同氮肥施入方式定量评价表明,缓控释肥料和秸秆还田处理的综合评价指标分别比优化施肥处理高出37%和30.1%,比农民习惯施肥处理高出了33.2%和27.5%。评价综合指标法和其指标有待于进一步研究完善。兼顾土壤培肥、产量品质、氮吸收和温室气体减排等因素,建议推广缓控释肥料在玉米田上的施用。更多还原

【Abstract】 In order to keep the corn yield as well as to fertile the soil and to reduce agricultural non-point source pollution from unreasonable fertilization, monitoring was carried in Linghai on soil, soil leaching solution, plant, greenhouse gas emission with practical nitrogen application modes by the methods of the in-situ soil solution collection and indoor soil column leaching simulation and manual static opaque chamber/gas chromatography and chemiluminescence measuring systems from2009to2011.At last, Integrated Evaluation Indexes of different nitrogen application treatments were calculated with quantitative evaluztion method.The results are as follows:1. Under the condition of natural rainfall in Linghai area, different nitrogen application modes couldn’t lead to the nitrogen leaching in the short term. Under the condition of soil column leaching simulation, leaching of soil available nitrogen increased with fertilizer rate. Leaching process of nitrate nitrogen from source of soil was relatively slow, while leaching of NO3-N from fertilizer was concentrated in the3～8times, accounting for86.7%of the total leaching rate. Nitrate nitrogen was the main form of nitrogen leaching. Straw returned treatment (OPTS) treatment lowered the water contents of soil in0-120cm layer.2. Nitrogen application disturbed the distribution of nitrogen in soil layers. Variation of available nitrogen in the shallow soil was greater than that of the underlying soil. NO3-N&NH4-N contents of soil increased with the rate of N application. Rotten process of straw consumed some nitrogen in earlier growing season, but later soil could buffer and recover itself. OPTS treatment could keep NO3-N from migrating to the underground and lowered the risk of polluting the groundwater. Released peak of control release fertilizer (CRF) lasted for30days and its NH4-N accumulation in soil increased by17.5%compared with farmers’ conventional N fertilizer treatment (FP).Apart from the soil pH, total&available NPK and soil organic matter content was lower than original contents.CRF could increase soil organic matter, total&available N contents. Straw could effectively increase the total&available K contents. Soil nutrient indexes of CRF was83.5. Effect of CRF on soil fertilization was better than that of OPTS.3. Chlorophyll contents of CRF and OPTS were higher in later growing season, good for photosynthesis to provide more nutrient to the grain. Along with the growth, water contents of stem, leaf and panicle decreased. Dry matter content of seed from CRF was highest. N contents of the whole plant increased with N application. Yield significant between treatments enhanced with years of the experiment. Average yields of3years of CRF and OPTS increased by3.3%and2.77%compared with FP; Annual N agronomic utilization efficiency and N harvest index and grain N accumulation of CRF were higher than those of OPTS, while the plant total N accumulation and fertilizer utilization rate of OPTS were higher.4. N2O emission flux was affected mainly by nutrients in the soil. The correlation coefficient between fertilizer rate and total N2O emissions was0.986. Total N2O emissions of CRF and OPTS were increased. During earlier stage of growing season N2O emission flux of CRF was influenced by fertilizer, while more affected by the soil temperature later. With the increase of planting years, seasonal N2O emissions coefficient less affected by yield than by fertilizer rate. Therefore the effect of different N application modes on seasonal N2O emission should be researched by monitoring year by year, and should consider the N2O emissions from plant.5. Apparent residual rate of CRF was1.4times higher than that of OPT treatment, and1.3times higher than that of OPTS treatment, while apparent loss rate was1/3of OPTS; Evaluation on different N application treatments with the method of Integrated Evaluation Index indicated that IEI value of CRF treatment and OPTS treatment were37%and30.1%higher than that of OPT treatment,33.2%and27.5%higher than that of FP treatment. The method of Integrated Evaluation Index, which considered about yield and environment and soil fertility promotion and resources utilizing was used to evaluate the result of the experiment, while the method and its evaluation indexes need to be perfected.Considering soil fertilizing and yield and as well as N absorb of plant and GHG emission reduction, control release fertilizer application was recommended.更多还原