【作者】 谷佳林；

【导师】 边秀举；

【作者基本信息】 河北农业大学 ， 作物栽培学与耕作学， 2013， 博士

【摘要】 本研究选取京郊常见的高羊茅草坪作为研究对象，采用田间小区和渗滤池试验相结合的方法，系统的研究了不同缓控释氮肥在草坪系统中的转化和去向，以及对草坪生长和氮素吸收影响。氮肥的三种主要损失途径即氨挥发、硝化反硝化和N2O排放、土壤残留及淋洗损失分别采用通气密闭室法，乙炔抑制-土柱培养法以及土钻动态采样与渗滤池试验相结合的方法测定。主要研究结果如下：1.施用氮肥可显著增加草坪草的生物量，尤其是PCU60处理可显著促进草坪草生长，提高草屑累积量和氮素吸收。连续两年的试验数据表明，2011年施氮处理的氮肥利用率在11.03%-23.07%之间，经过施肥时期的调控，2012年各施氮处理的氮素利用率提高到24.29%-45.28%，尤其是PCU60处理的氮素利用率达到了45.28%。在本试验中，养分释放期为60d树脂包膜控释尿素分春秋两季全量一次使用比等量普通尿素分4次施用的草坪草屑累积量显著提高。2.影响草坪氨挥发的主要因素是土壤中的铵态氮含量和pH值。氮肥的施入会在短时期内小幅度改变土壤pH值，各处理0-30cm土壤试验期间pH值均在7.10以上，这有利于氨挥发。施肥后灌溉或降水，可降低表层土壤氮的浓度而减少氨挥发，降水距施肥期越近，水量越大，氨挥发量越小。2011年PCU30、PCU60、SCU、UI和U处理的氨挥发损失量分别达到了17.67kg/hm2、13.59kg/hm2、18.54kg/hm2、44.42kg/hm2、39.53kg/hm2；2012年分别为24.63kg/hm2、19.51kg/hm2、28.26kg/hm2、55.74kg/hm2、53.96kg/hm2。挥发量数据表明，包膜缓控释氮肥能显著减少氨挥发，而添加硝化抑制剂DCD的UI处理氨挥发增加明显。3.2011年施氮处理的反硝化损失和N2O排放氮量占施氮量的1.79%-4.53%和0.89%-2.89%，2012年为1.94%-4.66%和0.80%-2.69%。与普通尿素相比，施用缓控释氮肥能显著降低反硝化损失和N2O排放，其中PCU60和UI处理效果明显。反硝化损失和N2O排放主要受温度的影响，温度越高反硝化损失和N2O排放越大。4.施用氮肥使0-30cm土层中的硝态氮和铵态氮浓度显著增加。2011年PCU30处理的土壤硝态氮残留达到了29.10kg/hm2，是施氮处理中最高的。2012年U处理土壤硝态氮残留最高，达到了36.31kg/hm2。渗滤桶试验数据表明，2011年和2012年各施氮处理通过淋洗损失的氮素数量较少。除土壤氮素残留、降水和灌溉外，土壤质地也是决定氮素淋洗的又一因素。试验期间的灌溉，加之频繁降雨，尤其是2012年7月21日的特大暴雨，但PCU30、PCU60、SCU、UI和U处理全年通过淋溶损失的可溶性氮量仅分别为1.54kg/hm2、0.94kg/hm2、2.07kg/hm2、2.10kg/hm2、1.73kg/hm2，这与试验地土壤质地偏粘有关。从数据来看，北京西南地区气候及土壤质地条件种植草坪，在现行的水肥管理模式下，肥料氮的淋洗损失量较低，但存在对土壤和地下水等环境方面的负面影响的风险。5.2011和2012年各施氮处理的氮素总损失量分别在40.74kg/hm2-82.03kg/hm2和45.75kg/hm2-94.45kg/hm2之间。其中氨挥发和硝化反硝化是最主要的损失途径，淋洗最低。2011年PCU30、PCU60、SCU、UI和U处理通过氨挥发损失的氮占施氮量的比例分别为：6.80%、5.23%、7.13%、17.08%、15.20%，通过硝化反硝化损失的氮占施氮量的比例分别为：2.75%、2.09%、3.25%、1.79%、4.53%。2012年通过氨挥发、硝化反硝化损失的氮量有明显的增加，但所占施氮量的比例变化不大。PCU30、PCU60、SCU、UI和U处理通过氨挥发损失的氮占施氮量的比例分别为：8.21%、6.50%、9.42%、18.58%、17.99%，通过硝化反硝化损失的氮占施氮量的比例分别为：2.49%、1.94%、3.71%、2.37%、4.66%。各施氮处理的氮素损失途径均表现出氨挥发>反硝化>淋洗的规律。更多还原

【Abstract】 Field plot and lysimeter experiments with tall fescue turf were conducted in Beijingsuburbs to investigate transformation and fate of applied difference slow/controlledrelease nitrogen fertilizer in turf systems. Effects of various slow/controlled-releasenitrogen fertilizers on plant growth, N uptake and N losses were studied during turfgrowth period. Ammonia volatilization was measured by the enclosure chamber method.Denitrification loss was measured by the acetylene inhibition-intact soil core technique,and N2O emission was also measured in the absence of acetylene. Soil auger dynamicsampling and lysimeter techniques were combined to study nitrate movement andleaching in soil profile. Main results of this study were summarized as follows:1. The application of nitrogen fertilizer significantly increased clipping yields of turf.The treatments of PCU60which nitrogen release period was60days could significantlyimprove growth of turfgrasses, clipping yields and nitrogen absorption. Two yearsexperimental data showed that the nitrogen use efficiency (NUE) of treatments whichapplied nitrogen were11.03%-23.07%in2011and24.29%-45.28%in2012whichchanged the fertilization period. It is worth noting that the NUE of PCU60was45.28%in2012. In the experiments, PCU60with single basal application in spring and autumncould significantly increased clipping yields of turf compared with urea with splitapplication of four times a year.2. Soil pH and ammonical N concentration in surface soil are the primary affectingfactors for ammonia volatilization of turf. The application of nitrogen fertilizers couldchange the soil pH in the small range within a short period of time.In the test site, pH of0-30cm soil was more than7.10which was beneficial to the volatilization of ammonia.Rainfall (or irrigation) following application of nitrogen fertilizer greatly reduced ammonia volatilization because rainfall reduces nitrogen concentration in the surface soil.The ammonia volatilization loss of applied nitrogen treatments of PCU30, PCU60, SCU,UI, U were17.67kg/hm2,13.59kg/hm2,18.54kg/hm2,44.42kg/hm2,39.53kg/hm2in2011and4.63kg/hm2,19.51kg/hm2,28.26kg/hm2,55.74kg/hm2,53.96kg/hm2in2012respectively. The results show that coated slow/controlled release nitrogen fertilizer couldreduce ammonia loss, and treatment of UI which mixed Nitrification inhibitors(Dicyandiamide, DCD) could improve ammonia loss.3. The results show that denitrification losses of nitrogen applied treatments rangedfrom1.79%to4.53%in2011and1.94%to4.66%in2012respectively, and N2Oemissions ranged from0.89%to2.89%in2011and0.80%to2.69%in2012respectively.Application of slow/controlled release nitrogen fertilizer could significantly decreasedenitrification losses and N2O emissions in comparison with urea, especially treatmentsof PCU60and UI. The denitrification losses and N2O emissions increased with theincrease of temperature.4. Application of nitrogen fertilizer could significantly increase concentration ofnitrate nitrogen and ammonium nitrogen in0-30cm soil. For example, the highest nitratecontent in applied nitrogen treatments was PCU30which reached29.10kg/hm2in2011.The situation has changed in2012. The highest nitrate content was U which reached36.31kg/hm2.There was little nitrogen loss by leaching in lysimeter experiments during2011and2012.In addition to soil nitrogen residues and rainfall(or irrigation), soil textureis the determined factor for nitrogen leaching. Although irrigation after fertilizing everytime and rainfall frequently, for example heavy rain in July21,2012, the solubilitynitrogen loss by leaching of applied nitrogen treatments of PCU30, PCU60, SCU, UI, Uwere1.54kg/hm2,0.94kg/hm2,2.07kg/hm2,2.10kg/hm2,1.73kg/hm2in2012respectively. This may be related to clay soil of field. It seems that leaching loss from turfwas low in the condition of climate and clay soil of southwest Beijing.But there is anegative influence risk of soil and groundwater negative effects.5. In the experiment, total N loss ranged from40.74kg/hm2to82.03kg/hm2in2011and from45.75kg/hm2to94.45kg/hm2in2012. The ammonia volatilization and denitrification were the most important N loss pathway.The leaching loss was lowest.The rate of nitrogen loss by ammonia volatilization of PCU30, PCU60, SCU, UI, U were6.80%,5.23%,7.13%,17.08%,15.20%in2011and8.21%,6.50%,9.42%,18.58%,17.99%in2012respectively. Compared with2011, the nitrogen loss by ammoniavolatilization and denitrification was increased significantly in2012.The rate of nitrogenloss by denitrification were2.75%,2.09%,3.25%,1.79%,4.53%in2011and2.49%,1.94%,3.71%,2.37%,4.66%in2012respectively. The nitrogen loss pathways of allnitrogen applied treatments are in order ammonia volatilization>denitrification>leaching.更多还原