【作者】 陈肖；

【导师】 张世熔；

【作者基本信息】 四川农业大学 ， 土壤学， 2007， 硕士

【摘要】 根据成都平原1982年土壤普查资料与2005年117个区域尺度样点和60个田间尺度样点的土壤氮素含量数据，基于ArcGIS9.0平台运用地统计学方法研究了区域尺度下成都平原区耕层（0～20cm）土壤氮素的空间分布和时空变异特征，采用常规统计分析和缓冲区分析、叠置分析等方法研究了2005年区域尺度和农田尺度下影响土壤氮素的主要因素，并通过田间试验地获得的数据和相关资料，对不同轮作方式下土壤氮素平衡状况进行估算。研究结果分述如下。区域尺度下成都平原土壤氮素含量呈现明显的时空变异特征。2005年土壤全氮平均含量为1.29±0.50g kg^-1，较1982年有所降低；高值区(＞2.00g kg^-1)位于崇州中部，并以此为中心向两侧呈带状减少，在郫县—温江一带和龙泉驿的西南部形成两个低值区(＜0.85g kg^-1)；与1982年相比，平原中部和西部除崇州外含量均有不同程度的降低。2005年土壤碱解氮平均含量为72.2±40.9mg kg^-1，低于1982年的112.4±53.6mg kg^-1；空间分布以崇州为中心向东和向西均呈先增后减的趋势，向南和向北都逐渐增加，高值区(＞110mg kg^-1)主要位于彭州、新津和新都的部分地区，低值区(＜30mg kg^-1)主要位于平原西南部边缘的大邑—邛崃一带；与1982年相比，碱解氮减少的区域占研究区总面积92.97％。从区域尺度和农田尺度两个方面，研究了影响土壤氮素的主要因素。区域尺度下，成都平原主要的4种第四系成土母质中，灰棕色冲积物上发育的土壤全氮极显著高于成都粘土和老冲积物，但与灰色冲积物差异不明显。缓冲区分析表明，在江安河—金马河，冲积物的土壤全氮和碱解氮随着缓冲距离的增加呈极显著的下降趋势，而在蒲阳河—毗河—北河则相反，在府河，全氮呈先增后减的变化，达到极显著相关水平，碱解氮则呈减—增—减变化。在不同土地利用类型之间，菜地和水田的全氮含量显著高于花卉地和旱地。由近年来施氮量的统计可知，土壤全氮和碱解氮含量高值区的施用量明显高于低值区。在距成都市主城区3.0km以内的城乡交错带，土壤全氮和碱解氮含量均随距离的增加呈极显著的增加。农田尺度下，府河冲积物的全氮含量显著或极显著低于江安河—金马河和毗河；从河流上游到下游，冲积物上层（0～20cm）全氮呈下降趋势，下层（20～40cm）则先增后减；在江安河—金马河中游两岸和下游东岸，冲积物全氮含量总体上随距离的增加先增后减，在下游西岸则呈显著或极显著的上升趋势，在毗河上游北岸冲积物全氮呈增—减—增变化，南岸则相反。在成都市主城区以外不同方向上，除主城区以南全氮含量随距离的增加总体呈上升趋势外，其余方向全氮总体上表现为先逐渐增加而后有所下降。2003～2005年田间试验地氮素平衡估算结果表明，两处农田都处于氮盈余状态，氮肥施用、前茬秸秆还田是氮素的主要来源，而作物吸收带走、化肥氮的损失是主要输出途径。其中，砂壤土试验地麦—稻和油—稻轮作下盈亏率分别为+7.08％和+23.34％，壤砂土试验地两个麦—稻轮作周期的盈亏率分别为+29.79％和+23.54％。更多还原

【Abstract】 According to the general detailed soil survey data of 1982 and the chemical analysis dataof soil nitrogen content which were from the 117 regional scale sampling points togetherwith 60 field scale sampling points of 2005, the spatial-temporal variation characteristicsof soil nitrogen at regional scale in Chengdu Plain were performed by the softwareArcGIS9.0, such as geostatistics. Also the influential factors of soil nitrogen werediscussed by routine statistical analysis, buffer analysis and overlay analysis, etc., atregional scale and field scale of 2005. Furthermore, the nitrogen equilibrium of differentcrop rotation types were evaluated by the data from the two test plots and other relatedinformation. The main results were as follows.At the regional scale, the content of soil nitrogen presented obvious spatial-temporalvariation characteristics. The results indicated that the content of soil total nitrogen （TN） was1.29±0.50 g kg^-1 in 2005, lower than the content in 1982. The highest value regions (＞2.00gkg^-1) of TN content were mainly distributed in the middle part of Chongzhou, and then reducedgradually towards both sides, presenting zonal shapes. The lowest value regions (＜0.85g kg^-1)were located in Pixian-Wenjiang and the southwest of Longquanyi. Comparing with the TNcontent in 1982, the plain of central and western had decreased in varying degrees exceptChongzhou. As far as soil available nitrogen （AN） was concerned, the content was72.2±40.9mg kg^-1, lower than the content in 1982. Taking Chongzhou as the center, the ANcontent first increased and then decreased towards its east and west, and graduallyincreased towards its south and north. Further more, the highest value regions (＞110mgkg^-1) were mainly distributed in some parts of Pengzhou, Xinjin and Xindu, while the twolowest value regions (＜30mg kg^-1) were mainly distributed in some part of Dayi-Qionglaiwhich was in the southwest edge zone of the plain. Comparing with the AN content in 1982,the decreased area accounting for 92.97％of the total.The influential factors of soil nitrogen were analyzed at both regional and field scale. At theregional scale, TN content of grey-brown alluvium from which soil derived was highlysignificantly higher than that of Chengdu clay and old alluvium among the four main parentmaterials of Quaternary System in Chengdu Plain, however there was no significant differencebetween the grey-brown alluvium and grey alluvium. Buffer analysis showed that, contrary tothat of Puyang-Pihe-Beihe River, soil TN and AN contents of alluvial deposit presented ahighly significant decreasing tendency as the expand of the buffer distance in Jiang’an-JinmaRiver. Moreover, TN content first increased and then decreased in Fuhe River, presentinghighly significant correlation, while AN content decreased before increasing, and then decreased. Among different land use types, TN content of the vegetable plot and paddy fieldwere both significantly higher than that of flower plot and dryland. From the statistical data ofthe nitrogen fertilizer application in recent years, the highest value regions of TN and ANcontents were both obviously higher than that in the lowest value regions. Furthermore, bothTN and AN contents were highly significantly increased as the increase of the distance in therural-urban fringe of 3.0km outside the Chengdu downtown. At the field scale, soil TN contentof alluvial deposit of Fuhe River was significantly higher than that of Jiang’an-Jinma Riverand Pihe River. From upper reach to lower reach of the rivers, TN content of alluvial deposit in0～20cm profile showed a decreasing tendency, but the content first increased and thendecreased in 20～40cm profile. In Jiang’an-Jinma River, alluvial deposit’s TN content ofmiddle reach’s side banks and lower reach’s east bank increased before decreasing, while in thewest river bank of lower reach, TN content showed significant or highly significant increasingtendency. Also, in Pihe River, alluvial deposit’s TN content of upper reaeh’s north river bankincreased before decreasing, and then increased, but the variation was just the contrary in thesouth river bank. It was also seen that, TN content increased gradually and then decreased as awhole in different directions outside the downtown, except the south which presented anincreasing tendency.Nitrogen equilibrium evaluation of field test from 2003 to 2005 showed that the two testplots were both in surplus condition. Moreover, nitrogen rate and straw residue were theprincipal sources, while crop absorption and loss of N fertilizer were the principal outputpaths. Thus the profit and loss rates were +7.08％and +23.34％in wheat-rice and rape-ricerotation of sandy loam field, and +29.79％and +23.54％in wheat-rice rotation of loamysand field, respectively.更多还原