【作者】 张玲娥；

【导师】 朱道林； 郝晋珉；

【作者基本信息】 中国农业大学 ， 土地资源管理， 2014， 博士

【摘要】 我国人多地少的矛盾十分突出,耕地质量对于保障我国粮食安全十分重要。本文以黄淮海平原地区粮棉油典型集约化生产区之一的曲周县为研究对象,通过2010年实地采样和收集1980年和2000年土壤数据的基础上,采用GIS技术与地质统计学结合的方法,研究了曲周县耕地土壤有机质、全氮、速效磷和速效钾的时空变异特征及演变规律,分析了该区土壤类型、土壤质地、土地利用和人为管理措施对各土壤养分的影响,最后应用耕地肥力质量综合指数法定量评价了该区耕地肥力质量的变化,剖析了耕地肥力质量演变的驱动因子,得到如下主要结论：1980年、2000年和2010年三个时期,土壤有机质的平均含量分别为8.8、12.9和14.0g/kg,土壤全氮的平均含量分别为0.6、0.7和1.0g/kg,土壤速效磷的平均含量分别为5.2,8.8和23.4mg/kg,均表现为随时间的推移呈递增的趋势。前20年(1980-2000)土壤有机质的增幅较大；后10年(2000-2010)的增长较小,而土壤全氮和速效磷的增幅刚好相反,特别是速效磷后10年的增幅远大于前20年的增幅。3个时期土壤速效钾的平均含量分别为167.1、90.0和87.7mg/kg,表现为随时间的推移呈递减的趋势,前20年下降很快,后10年表现为总体略有下降,但局部地区有上升的趋势。30年间土壤有机质含量增幅在4～6g/kg的面积最大,占到了总面积的52.1%。前20年增加范围大部分处于2～4g/kg和4～6g/kg分别占到总面积的57.0%和43.0%；后10年,其含量有增有减,其中含量提高的面积占绝大部分,达到83.4%。30年间土壤全氮含量增幅在0.3～0.5g/kg的面积最大,占总面积的63.6%。前20年土壤全氮含量基本表现为增加,增幅在0.1～0.3g/kg的面积最大,占总面积的73.5%；后10年提高范围在0.1～0.3g/kg的面积占大多数,达到64.2%。30年间土壤速效磷含量增幅在10～20mg/kg的面积最大,占到了总面积的38.2%,其次是增幅在20～30mg/kg的占总面积的33.1%。30年间土壤速效钾含量降幅在-100～-60mg/kg的面积最大,占总面积的60.8%,前20年降幅大部分处于-120～-60mg/kg,占到总面积的90%。后10年土壤速效钾的含量有增有减,其中含量提高或保持不变的面积占绝大部分,达到80.7%，而含量下降的面积只有19.3%。从曲周县在30年间耕地养分变化的规律来看,土壤有机质和全氮具有高度的相似性。其含量增加最高的区域集中在曲周镇、第四疃镇：土壤速效磷含量增加最高的区域也位于该区,同时槐桥乡增加也明显；土壤速效钾含量增加最高的区域在第四疃镇,其次在曲周镇和槐桥乡。构建了基于负指数函数的土壤有机碳垂向分布模型,结果表明土壤有机碳含量随深度增加呈逐渐递减的规律,各土层有机碳含量均属于中等变异程度。0-20cm和20-40cm土壤有机碳空间连续性较好,它们的相关距离分别为14km和3km,而下层(>40cm)土壤有机碳均表现为纯块金效应结构。土壤有机碳垂向分布模型可以很好地描述剖面土壤有机碳含量的变化特征,且预测与实测的土壤有机碳含量的均方根误差和决定系数分别达到0.70和0.94。土壤有机碳密度的空间分布与土壤质地的分布比较相似,呈现西北高东南低的空间分布特征。土壤类型、土壤质地、土地利用方式下土壤养分含量各不相同。土壤类型对土壤养分的影响总体遵循：潮土>褐土化潮土>盐化潮土>盐土,即潮土的各养分含量较高；质地对土壤养分的影响总体遵循：粘土>中壤>轻壤>砂壤>砂土的规律,即质地越粘,养分含量越高。土地利用方式对不同养分的影响各不相同。1980年不同土地利用类型的有机质、全氮和速效钾含量顺序为：水浇地>旱地>林地,而2000年和2010年均为林地>水浇地>旱地。1980年土壤速效磷含量大小顺序为：旱地>水浇地>林地,而2000年和2010年顺序为：林地>水浇地>旱地。根据耕地肥力质量综合指数的空间分布及变化,可以看出,耕地肥力质量综合指数随着时间的推移呈逐渐增大的趋势,2000年和2010年I等地的比例分别为6.3%和40.7%,Ⅱ等地的比例分别为64.2%和51.1%, Ⅲ等地的比例分别为29.5%和8.2%。对于耕地肥力质量综合指数的变化,前20年的耕地肥力质量综合指数均为增加,后10年增加的比例达到了78.5%。增幅为0.2--0.3的区域出现在曲周实验站及其周边地区,但部分地区也出现了质量下降的情况,占到总面积的21.5%。土地利用变化和人为活动对耕地肥力质量影响较大。前20年,土壤有机质和全氮的变化非常相似,除水浇地转为林地的有机质和全氮含量增幅较大,分别达到124.22%和146.94%外,其余土地利用变化类型的有机质含量增幅基本处于34.66%-68.38%之间,全氮增幅处于19.64%-54.35%之间,其中增幅最大的均是林地,最小的为旱地转为水浇地类型。后10年,当土地利用类型发生变化时,除了部分耕地的有机质含量稍有下降外,其余土壤养分含量都表现为增加的趋势,其中以速效磷含量的增加最为明显。农民对土地的投入水平(化肥和有机肥)、秸秆还田等人为活动对于提升耕地质量起到了十分重要的作用。更多还原

【Abstract】 There is a outstanding contradiction between the large population and little arable land. Arable land quality provides a protection for the food safety. The research was carried in Quzhou County (Hebei Province, China)——A typical alluvial regions of Huang Huai Hai Plain. We collected and measured the contents of soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP) and available potassium (AK) in the0-100cm in1980,2000and2010. The geostatistical method combined with GIS technique was used to analyze the spatio-temporal variability of soil attributes. The main influencing factors such as soil type, soil texture, land use type and farming practices were analyzed. At the same time, the change of soil quality has been evaluated applying to the method of soil quality compressive index to dissect the driving force of Soil quality evolvement. The main results were as follows.It showed that the average SOM contents were8.8,12.9, and14.0g kg-1in1980,2000and2010, respectively; the average TN contents were0.6,0.7, and1.0g kg-1in1980,2000and2010, respectively; the average AP contents were5.2,8.8, and23.4mg kg-1in1980,2000and2010, respectively. The results showed the increasing trend with the time for the three soil nutrients. There was the larger increase for SOM in1980-2000and the smaller increase in2000-2010. There were smaller increase for TN and AP and larger increase for them. The average AK contents were167.1,900., and87.7mg kg-1in1980,2000and2010, respectively. It showed the decreasing trend with the time. There was the larger decrease in1980-2000and smaller decrease in2000-2010, meanwhile there was some increase in some regions.For SOM, the largest area which the amplification was4-6g kg-1accounted for52.1%in1980-2010. The area which the amplification was2-4g kg-1and4-6g kg-1accounted for57.0%and43.0%respectively in1980-2000. The increased area accounted for83.4%in2000-2010. For TN, the largest area which the amplification was0.3-0.5g kg-1accounted for63.6%in1980-2010. All of the TN content increased in1980-2000and the lagest area which the amplification was0.1-0.3g kg-1accounted for73.5%. The increased area accounted for64.2%in2000-2010. For AP the largest area which the amplification was10-20mg kg-1accounted for38.2%and the area which the amplification was20-30mg kg-1accounted for33.1%in1980-2010. For AK the largest area which the reduction was-100--60mg kg-1accounted for60.8%in1980-2010. The area which the reduction was-120--60mg kg-1accounted for90.0%in1980-2000. The increased area accounted for80.7%in2000-2010.The distribution of soil nutrients had the rules as follows:SOM and TN had the high similarity. The area that had the most content increase lies in Quzhou and Disitan town. For AP, this kind of area lies in Quzhou, Disitan and Huaiqiao town. For AK, this kind of area lies in Disitan town, the next class lies in Quzhou and Huaiqiao town.The vertical distribution model of SOC was constructed based on negative exponential function. SOC contents showed a gradually decreasing trend with the increase of soil depth, and SOC contents for all layers were belong to moderate degree of variation. The spatial continuity was better for SOC in0- 20cm and20～40cm, and their correlation distances were14km and3km, respectively. However, SOC in subsoil (>40cm) showed a pure nugget effect. The vertical distribution model can well describe the changes of SOC content with the increasing of depth, the root mean squared errors and the coefficients of determination of the predicted and measured SOC contents reached to0.70and0.94, respectively. Spatial distribution of SOC density was similar to the distribution of soil texture, both showed a decreasing trend from northwest to southeast across the county.The contents of soil nutrients for different soil types had the following order:Fluvo-acquic soi1> Drab fluvo-acquic soil> Salined fluvo-acquic soil> Saline soil. That for soil textures had the following order:clay> medium loam> light loam> sandy loam> sand. That for land use thpes, the SOM, TN and AK had the similar order:irrigated land> dryhad> forestland in1980and forestland> irrigated land> dryland in2000and2010. The order of AP content is dryland> irrigated land> forest land in1980and forest land> irrigated land> dryland in2000and2010.According to the distribution and changing of the SQI, the SQI increased with the time gradually. In2000and2010, The area of I-class land occupied6.3%and40.7%, that of Ⅱ-class land occupied64.2%and51.1%, that of the Ⅲ-class land occupied29.5%and8.2%. The SQI increased in1980-2000and there is78.5%increasing land in2000-2010.The change of land use and managing measures had the great effects on soil qualities. The change of SOM and TN had the simililarity in1980-2000:except "irrigated land to forest land" had the greater amplification, had the124.22%and146.94%, other amplification were34.66%-68.38%and19.64%-54.35%respectively. When the land use change occurred in2000-2010, the soil nutrients showed increasing trend except the SOM which had decreased partly in some land use change. AP had the greatest increase.Managing measures such as straw return, fertilizer application based on soil testing technology had the important role in effectively increasing the soil quality.更多还原