【作者】 代天飞；

【导师】 邓良基；

【作者基本信息】 四川农业大学 ， 生态学， 2021， 博士

【摘要】 过多的养分输入不仅造成资源浪费,提高农业生产成本,降低农业生产效益,还会给环境带来不利影响。本研究以四川省农田生态系统为研究对象,利用生态学理论、生态系统理论、黑箱理论和质量守恒定律,将农田生态系统的土壤子系统设为黑箱,基于收集整理的第二次土壤普查土壤样点数据、2017年采样分析的土壤样点数据,以及1980-2017年全省耕地面积、施肥量和作物产量等数据,运用数理统计和差分整合移动平均自回归模型等方法,研究农田生态系统土壤子系统的养分输入、累积、输出特征,厘清土壤子系统的养分输入特征,农田生态系统内土壤、作物、大气环境和水环境子系统的养分累积与输出特征及其变化规律,分析农田生态系统养分表观盈亏,并对其进行预测评价。主要研究结果如下。（1）四川省农田生态系统土壤子系统养分输入特征。1980-2017年,土壤子系统养分输入途径主要有化肥施用、秸秆还田、畜禽粪尿施用、人粪尿施用、灌溉、大气沉降、种子和固氮等,总养分输入量为14603万t,其中,输入氮（N）占输入总养分的49.68%、磷（P₂O₅）占输入总养分的22.30%,钾（K₂O）占输入总养分的28.02%。全省土壤子系统总养分输入强度为570 kg·hm^-2·a^-1。各区域输入养分总量以川东北丘陵区最高,占全省总输入量的35.79%,川西北高原区最低,仅占1.64%。全省土壤中总养分输入途径以化肥为主,占输入总量48.1%;其次为秸秆和畜禽粪尿,分别占输入总量的18.3%和16.3%,其他途径总养分输入量仅占17.3%;氮和磷输入均以化肥为主,钾输入以秸秆为主。除川西北高原区总养分、氮、磷和钾输入以畜禽粪尿为主外,其余区域总养分、氮和磷输入均以化肥为主,钾输入均以秸秆还田为主。全省和各区域土壤子系统中总养分、氮、磷和钾的输入量均呈波动增加趋势,其增幅以川西北高原区最大。（2）四川省农田生态系统土壤子系统养分累积特征。2017年四川省土壤有机质、全氮、全磷和全钾含量均处于较高水平,与1980年相比,呈增加趋势。1980-2017年,全省农田生态系统土壤子系统累积的总养分为3756万t,占总养分输入量的25.72%,其中氮的累积量占总养分输入量的10.70%,磷的累积量占总养分输入量的11.27%,钾的累积量占总养分输入量的3.76%。全省土壤子系统总养分累积强度为146.7 kg·hm^-2·a^-1,其中氮、磷和钾的累积强度分别为61.0kg·hm^-2·a^-1、64.3 kg·hm^-2·a^-1和21.4 kg·hm^-2·a^-1。四川省农田生态系统土壤子系统养分的累积以磷为主,占磷输入总量的50.5%;其次是氮,占氮输入总量的21.5%,钾累积量最低,占钾输入总量的13.4%。各区域土壤子系统氮的累积强度差异不明显,磷的累积强度以成都平原区最高,钾以川西北高原区最高。（3）四川省农田生态系统作物子系统养分累积特征与养分有效率。1980-2017年,全省作物子系统总养分累积量为8966万t,占土壤子系统养分输入量的61.4%,其中氮、磷、钾累积量分别占总养分输入量的28.20%、9.84%、23.36%,单位面积的总养分累积量为350 kg·hm^-2·a^-1。作物子系统累积养分的效率是钾最高,累积量占土壤子系统钾输入量的83.4%,氮次之,累积量占土壤子系统氮输入量的56.8%;磷最低,累积量占土壤子系统磷输入量的44.1%。作物子系统中总养分、氮、磷和钾的累积强度均以成都平原区最高,川西北高原区最低。全省和各区域作物子系统总养分、氮、磷和钾累积量以粮食作物为主。全省作物子系统总养分累积量增长了89.8%,其中氮、磷和钾的累积量增幅分别为90.7%、76.1%和94.7%。各区域作物子系统总养分、氮、磷和钾累积量呈波动增加趋势,但是增幅和变化趋势存在明显差异。全省氮、磷和钾有效率分别为78.3%、94.6%和96.7%,各区域的有效率存在一定差异,但是差别不大。（4）四川省农田生态系统养分表观盈亏特征及影响因素。1980-2017年,全省农田生态系统总养分表观盈余强度为221kg·hm^-2,总养分、氮、磷和钾的表观盈余量分别占土壤子系统输入量的38.6%、43.2%、55.9%和16.6%。成都平原区的氮和磷表观盈余强度最高,川西北高原区的钾表观盈余强度最高。全省土壤子系统的总养分、氮和磷为盈余状态,且波动增长;钾在1990年以前呈亏缺状态,1991年钾扭亏为盈后,呈波动增长趋势。各区域土壤子系统总养分、氮、磷的表观盈余量呈增长趋势。1992年以前,除川西北高原区和攀西山地区土壤子系统的钾有小幅盈余外,其余区域均为亏缺状态;1992年扭亏为盈后,各个区域钾表观盈余量均开始迅速增加。养分表观盈亏量与农业总产值、城镇化率、人口密度、养分输入量、作物总产量呈极显著正相关,与粮经面积比呈极显著负相关。（5）四川省农田生态系统土壤子系统向水环境和大气环境子系统输出养分的特征。四川省农田生态系统土壤子系统输出到水环境子系统和大气环境子系统的总养分量为1882万t,其中输出的氮、磷、钾的量分别占土壤子系统总养分输入量的10.78%、1.19%和0.92%,分别占土壤子系统相应养分输入量的21.7%、5.4%和3.3%。氮以输出到大气环境子系统为主,各区域氮输出强度差异不大;氮输出到水环境子系统的强度以成都平原区最高,通过地表径流的输出量高于地下淋溶。输出到水环境的磷强度以成都平原区最高,而钾以川西北高原区最高。（6）四川省农田生态系统养分表观盈亏预测评价。2018-2030年,全省农田生态系统养分表观盈亏将延续近期的下降趋势,其中钾的下降幅度最大。川西北高原区总养分、氮、磷和钾表观盈余强度的预测结果均呈上升趋势,其余4个区域均呈下降趋势。全省农田生态系统氮表观盈亏在1990年进入潜在风险期,预计将在2023年降至无风险水平。各区域的氮表观盈亏于1990-2000年间陆续进入潜在风险期;至2030年,川西北高原区仍为潜在风险,其余区域为无风险。全省农田生态系统磷表观盈亏在1994年进入潜在风险期,至2030年仍为潜在风险。各区域的磷表观盈亏于1994-2000年间陆续进入潜在风险期,至2030年,川西北高原区可能仍为将高风险,川东北丘陵区和攀西山地区为潜在风险,其余区域为无风险。更多还原

【Abstract】 Excessive nutrients input not only causes waste of resources,increases the cost of agricultural production,reduces the benefit of agricultural production,but also causes the adverse effects on the environment.In this study,the cropland ecosystem in Sichuan Province was taken as the research object,based on the ecological theory,black box theory,ecosystem theory and material balance theory,the soil subsystem of the cropland ecosystem was set as the black box;then,using the soil data from the Second National Soil Survey in the 1980 and samples collecting in 2017,and the data of cropland acreage,fertilization and production of crop and so on from 1981 to2017 in Sichuan Province,we analyzed the characteristics of nutrients input,accumulation and output of the cropland ecosystem by mathematical statistics and the nonseasonal mixed autoregressive moving average model（ARIMA）,to explore the characteristics and the changing rules of nutrients input,accumulation,output in soil,crop,atmospheric and water subsystem,the characteristics of the apparent profit-loss nutrients in the cropland ecosystem,to predict and evaluate the apparent profit-loss nutrients in the cropland ecosystem.The main findings are as follows.（1）Nutrients input characteristics in soil subsystem of the cropland ecosystem in Sichuan Province.From 1980 to 2017,the ways of nutrients input to soil subsystem mainly included chemical fertilizers,crop straw,livestock manure and urine,human manure and urine,irrigation,atmospheric deposition,seed and nitrogen fixation,etc.,and the amount of the total nutrients（sum of nitrogen,phosphorus and potassium,the same as below）input to soil subsystem was 146.03 million tons,of which the nitrogen（N）input accounted for 49.68%,the phosphorus（P₂O₅）input accounted for 22.30%and the potassium（K₂O）input accounted for 28.02%.The intensity of total nutrients input to soil subsystem in Sichuan Province was 570 kg·hm^-2·a^-1.The amount of the total nutrients input to soil subsystem in the Northeast Hilly of Sichuan Province was the highest,accounted for 35.79%of the whole province,and in the Northwest Plateau of Sichuan was the lowest,accounted for only 1.64%.Chemical fertilizer was the main input way of the total nutrients in Sichuan Province,accounted for 48.1%of the total input,secondly,crop straw,livestock manure and urine accounted for 18.3%and 16.3%of the total input,respectively,and the total nutrients input to soil subsystem by other ways accounted for only 17.3%.Chemical fertilizer was the main input way of the nitrogen and phosphorus in Sichuan Province,while the potassium was mainly input by crop straw.The total nutrients,nitrogen,phosphorus and potassium in the Northwest Plateau of Sichuan were mainly input by livestock manure and urine,while the input of the total nutrients,nitrogen and phosphorus in other regions were mainly input by chemical fertilizer,and the input of potassium were mainly by crop straw.The amount of the total nutrients,nitrogen,phosphorus and potassium input to the soil subsystem in Sichuan Province and all regions were showed a fluctuating increasing trend,and the increasing rate in the Northwest Plateau of Sichuan was the largest.（2）Nutrients accumulation characteristics of soil subsystem of the cropland ecosystem in Sichuan Province.In 2017,the contents of soil organic matter,total nitrogen,total phosphorus and total potassium in Sichuan Province were all at a high level,and were higher than that in 1980.From 1980 to 2017,the amount of accumulation in the soil subsystem of the total nutrients in Sichuan Province was 37.56 million tons,accounted for 25.72%of the total nutrients input,of which the nitrogen accumulation accounted for 10.70%of the total nutrients input,the phosphorus accumulation accounted for 11.27%of the total nutrients input,and the potassium accumulation accounted for 3.76%of the total nutrients input.The intensity of the total nutrients accumulation in the soil subsystem in Sichuan Province was 146.7 kg·hm^-2·a^-1,in which the nitrogen,phosphorus and potassium accumulation in the soil subsystem were 61.0 kg·hm^-2·a^-1、64.3kg·hm^-2·a^-1和21.4 kg·hm^-2·a^-1,respectively.The phosphorus accumulation in the soil subsystem of cropland ecosystem in Sichuan Province was the highest,accounted for 50.5%of the total phosphorus input,the second was nitrogen,accounted for 21.5%of the total nitrogen input,and the potassium accumulation was the lowest,accounted for 13.4%of the total potassium input.There was no significant difference of the nitrogen accumulation intensity in soil subsystem in different regions.The phosphorus accumulation intensity in soil subsystem in the Chengdu Plain was the largest,while the potassium accumulation intensity in soil subsystem in the Northwest Plateau of Sichuan was the largest.（3）Nutrients accumulation characteristics and nutrients efficiency of crop subsystem of the cropland ecosystem in Sichuan Province.From 1980 to 2017,the amount of the total nutrients accumulation in crop subsystem in Sichuan Province was 89.66 million tons,accounted for 61.4%of the total nutrients input to soil subsystem,of which the nitrogen,phosphorus and potassium accumulation in crop subsystem accounted for 28.20%,9.84%and 23.36%of the total nutrients input to soil subsystem,respectively.The intensity of the total nutrients accumulation in crop subsystem was 350 kg·hm^-2·a^-.The efficiency of potassium accumulation in crop subsystem was the highest,accounted for 83.4%of the potassium input to soil subsystem,the second was nitrogen,accounted for 56.8%of the nitrogen input to soil subsystem,and the phosphorus was the lowest,accounted for 44.1%of the phosphorus input to the soil subsystem.The accumulation intensity of total nutrients,nitrogen,phosphorus and potassium in the crop subsystem were the highest in the Chengdu Plain and were the lowest in the Northwest Plateau of Sichuan.The total nutrients,nitrogen,phosphorus and potassium accumulation in crop subsystem in Sichuan Province and all regions were dominated by grain crop.The total nutrients accumulation in the crop subsystem increased by 89.8%,and the accumulation of nitrogen,phosphorus and potassium increased by 90.7%,76.1%and 94.7%,respectively.The total nutrients,nitrogen,phosphorus and potassium accumulation in the crop subsystem in all regions showed a fluctuating increasing trend,but the increasing and changing trends were obvious different in different regions.The effective rates of nitrogen,phosphorus and potassium in Sichuan Province were 78.3%,94.6%and 96.7%,respectively,and there were some differences in different regions,but the differences were not significant.（4）The apparent profit-loss characteristics of nutrients and its influencing factors of the cropland ecosystem in Sichuan Province.From 1980 to 2017,the apparent profit-loss intensity of total nutrients in cropland ecosystem was 221kg·hm^-2,and the apparent profit-loss of total nutrients,nitrogen,phosphorus and potassium accounted for 38.6%,43.2%,55.9%and 16.6%of the amount of that input to soil subsystem,respectively.The apparent profit-loss intensity of nitrogen and phosphorus in the Chengdu Plain was the highest,and that in the Northwest Plateau of Sichuan was the highest.The apparent profit-loss of total nutrients,nitrogen and phosphorus in cropland ecosystem in Sichuan Province were in surplus and increased fluctuant.The apparent profit-loss of potassium in cropland ecosystem in Sichuan Province was deficient before 1990,but it showed a fluctuating increasing after it turn to surplus in 1991.The apparent profit-loss of total nutrients,nitrogen and phosphorus in cropland ecosystem showed an increasing trend in different regions.Before 1992,the apparent profit-loss of potassium in the cropland ecosystem in the Northwest Plateau of Sichuan and the Panxi Mountain had a little surplus,but that in the other regions were deficient.After turn from deficit to profit in 1992,the apparent profit-loss of potassium in all regions began to increase rapidly.Nutrients apparent profit-loss were significantly positively correlated with the gross value of agricultural,urbanization rate,population density,nutrients input,and the total crop yield,and negatively correlated with the area ratio of grain crops to economic crops.（5）Nutrients output characteristics from soil subsystem to water and atmospheric subsystem of the cropland ecosystem in Sichuan Province.The amount of the total nutrients output from the soil subsystem to the water environment subsystem and the atmospheric environment subsystem in the cropland ecosystem in Sichuan Province was 18.82 million tons,of which the output of nitrogen,phosphorus and potassium accounted for 10.78%,1.19%and 0.92%of the total nutrients input to the soil subsystem,respectively,and accounted for 21.7%,5.4%and 3.3%of that input to soil subsystem,respectively.The nitrogen output was mainly to the atmospheric subsystem,and there was a little difference of the nitrogen output intensity in different regions.The intensity of the nitrogen output to the water subsystem in the Chengdu Plain is the highest,and the output to the water subsystem through surface runoff was higher than that through underground leaching.The intensity of phosphorus output to the water subsystem in the Chengdu Plain was the highest,while the intensity of potassium output to the water subsystem in the Northwest Plateau of Sichuan was the highest.（6）The prediction and evaluation of nutrients apparent profit-loss of the cropland ecosystem in Sichuan Province.From 2018 to 2030,the nutrients apparent profit-loss of cropland ecosystem in Sichuan Province will keep the recent trend of decline,with the largest decline of potassium.The predicted results of the apparent profit-loss intensity of total nutrients,nitrogen,phosphorus and potassium in the Northwest Plateau of Sichuan all show an upward trend,while that in the other regions show a downward trend.The nitrogen apparent profit-loss of cropland ecosystem in Sichuan Province entered the potential risk in 1990 and will be expected to decrease to the level of no risk in 2023.The apparent profit-loss of nitrogen in all regions gradually entered the potential risk from 1990 to 2000.By 2030,the apparent profit-loss of nitrogen in the Northwest Plateau of Sichuan will be still at potential risk,while that in the other regions will be not at risk.The phosphorus apparent profit-loss of cropland ecosystem in Sichuan Province entered the potential risk in 1994,and will be remaining at the potential risk until 2030.The apparent profit-loss of phosphorus in all regions gradually entered the potential risk from1994 to 2000.By 2030,the apparent profit-loss of phosphorus in the Northwest Plateau of Sichuan will be still at high risk,while that in the Northeast Hilly of Sichuan Province and the Panxi Mountain will be at potential risk,and that in the other regions will be at no risk.更多还原