【作者】 郭琳琳；

【导师】 依艳丽；

【作者基本信息】 沈阳农业大学 ， 土壤学， 2009， 硕士

【摘要】 沈阳市大部分耕地存在过量施用化肥,有机无机配施不合理及耕作制度单一等现象,势必对土壤的肥力状况产生一定影响。本文采用野外采样与室内分析相结合的方法,以沈阳市东陵区和苏家屯区东部的典型耕地棕壤为研究对象,对耕地棕壤的肥力现状、变化趋势进行研究。运用指数和法和模糊分析法相结合,对土壤进行综合肥力评价,明确土壤肥力障碍因子并提出培肥措施,研究结论如下:1.供试区耕地棕壤养分状况为:土壤有机质含量为20.10±4.03g kg^-1,53.28%土样为较缺水平。土壤全氮(1.19±0.35g kg^-1)和碱解氮(113.05±26.77 mg kg^-1)含量大部分为中等或丰富等级;速效磷含量为23.57±14.94 mg kg^-1,52.68%土样为丰富和很丰富等级。速效钾含量为76.10±26.81mg kg^-1,85.22%处于缺乏水平;CEC平均值为17.22±2.66cmol kg^-1,土壤保肥能力处于中等水平。土壤各养分指标的空间变异性不大,但速效磷的空间变异相对较高。不同养分指标的空间分布状况不同,但供试区北部养分整体含量相对较丰富。有效钙镁元素的含量全部在临界值之上。供试区棕壤微量元素含量的空间分布差异较大,但含量均较丰富,只有7.14%的土壤有效锌含量略有缺乏。2.与第二次土壤普查（1982年）资料相比耕地棕壤的养分和有机质含量发生了明显的变化:有机质含量、全氮、碱解氮和速效磷均呈上升趋势,有机质从17.7g kg^-1上升到20.01g kg^-1;土壤全氮从1.01g kg^-1上升到1.19g kg^-1,增加了17.82%;碱解氮含量从89.20mg kg^-1上升到113.05mg kg^-1增加了26.74%;速磷含量从8.20mg kg^-1上升到23.57mg kg^-1,增加十分显著,达187.32%;而速效钾含量呈下降趋势,由108mgkg^-1下降到76.10 mg kg^-1。3.研究区的耕地棕壤的pH值呈下降趋势,1982年研究区的土壤pH值在5.1～7.5之间,平均为6.48;2008年在4.5～7.6之间,平均值为5.60,其中呈酸性（pH＜5.5）的土样占总数的54.63%,与二次土壤普查相比土壤pH值平均下降了0.88。4.分析研究区耕地棕壤酸化原因,土壤盐基饱和度降有降低趋势,导致土壤酸化。盐基饱和度在53.51%～92.94%范围内,平均为69.91%,pH值在5.5之下的土壤盐基饱和度平均值为61.67%;盐基饱和度与pH值呈极显著的正相关,r=0.7502^**,盐基离子组成中Ca²⁺数量较多,其次是Mg²⁺,而K⁺和Na⁺数量很少,土壤Ca²⁺饱和度平均值为43.63%,Ca²⁺饱和度与土壤pH值相关性极显著,r=0.7718^**。环境因素、不合理施肥耕作措施,耕作制度单一等因素也可能导致土壤的酸化。5.研究区内的土壤质地多为粉质壤土。土壤的容重平均为1.15 g cm^-3,总孔隙度平均值为56.65%,毛管孔隙度平均值为43.48%,上述土壤物理性指标在适宜作物生长的数值范围之内,且在空间分布上差异不大;但是耕层土壤的通气孔隙度平均值仅为12.81%,其中33.34%土样的通气孔隙低于10%,土壤通气孔隙度偏低。粒径＞0.25mm的风干土团聚体含量平均值达80.44%,但是其中＞0.25mm的水稳性团聚体平均值仅为22.29%,水稳性系数平均值为0.29,土壤水稳性团聚体的质量差。6.耕地棕壤的耕层厚度变浅、犁底层厚度增加,影响作物生长。研究区耕层厚度在7.5～25cm之间,平均厚度为15.45cm,耕层厚度小于15cm的土样占49.09%。与第二次土壤普查数据相比耕层厚度平均下降了2.36cm,而犁底层厚度增加2.97cm。7.选取对土壤肥力贡献率较大的十一项指标,运用相关系数确定权重法和模糊分析法对研究区土壤进行肥力综合评价,结果为:研究区耕地棕壤肥力整体处于中等偏上水平,但没有样品的肥力指数达到高水平（肥力综合指数＞0.8）;肥力处于偏高水平（肥力综合指数0.6～0.8）的土样占50.00%;肥力综合指数＜0.5的土样占10.64%。限制研究区土壤肥力的主要因素有:土壤有机质含量不高;土壤养分不平衡,速效钾含量相对较低;土壤结构性较差,稳定性团聚体含量少;土壤耕层变浅、犁底层厚度增加;土壤pH值下降,土壤酸化趋势明显。更多还原

【Abstract】 There are some phenomena about most arable soil in Shenyang,such as excessively using chemical fertilizer,unreasonable coordination application of organic manure and chemical fertilizer,singleness cultivation and so on.All of phenomena influence the soil fertility to some extent.This paper made a study of the soil fertility status,the soil fertility evolutionary trends of soil fertility on typical arable brown soil of Dongling and the east of Sujiatun sections in Shenyang,with the methods of sampling in the open air and indoor analysis.The evaluation has been made on the soil integrate fertility used the methods of weight coefficient and the method of vague analysis,and then realize the obstacle factors, fertility-building measures.The results as following:1 The following is the nutrients status of arable brown soil.The content of organic matter is 20.10±4.03g kg^-1 and 53.28%of the soil samples are in the relatively low level. The content of total nitrogen(1.19±0.35g kg^-1) and available nitrogen(113.05±26.77 mg kg^-1) are mostly in medium and relatively high level.The content of available phosphorus is 23.57±14.94mg.kg^-1 and 52.68%of the soil samples are in the rich or relatively high level. The content of available potassium is 76.10±26.81mg·kg^-1 and 85.22%of soil samples are lack level.The average number of the CEC is 17.22±2.66cmol kg^-1,which is in the middle level.The variation of soil nutrients is not high except the available phosphorus.The spatial distribution of different nutrient item is not consistent,but the nutrients content of the north section are relatively rich.The content of available calcium and the magnesium are higher than the limit values.The variation range of trace elements in arable brown soil is large,but the content is rich.Only 7.14%of available zinc is relatively deficiency.2 Comparing with the data of the second soil general survey,the content of some nutrients and organic matter ascend a little.The content of organic matter increases from 17.7g kg^-1 to 20.01g kg^-1.The content of total nitrogen increase from 1.01g kg^-1 to 1.19g kg^-1.The content of available nitrogen increases from 89.20mg kg^-1 to 113.05mg kg^-1（increasing 26.74%）.The content of available phosphorus has a obvious uptrend （increasing 187.32%）,increasing from 8.20mg kg^-1to23.57mg kg^-1.The content of available potassium decreases from 108 mg kg^-1 to 76.10 mg kg^-1.3.The pH value of arable brown soil has a downtrend.The pH value is between 5.1 and 7.5 in 1982 and average value is 6.48.The pH value is between4.5 and 7.6 in 2008 and average value is 5.60.The pH value of 54.36%arable brown soil doesn’t reach 5.5.The acidification is serious.Compared with the data of the second soil general survey,the pH value decrease 0.88.4.Analysis on the reason of soil acidification,the BS of arable brown soil has a downtrend.The BS changes from 53.51%to 92.94%,and the average BS is 69.91%.The average BS percentage of the soil samples is only 61.91%,pH of which is under 5.5.The relation between BS and pH are in notable positive correlation,r=0.7502^**.There were more Ca²⁺ and Mg²⁺ in composition of base ions.The amount of K⁺ and Na⁺ are less in composition of base ions.The study also shows that Ca²⁺ saturation is 43.63%.The relation between Ca²⁺ saturation and pH is in positive correlation too,r=0.7718^**.Environment factor,unreasonable fertilization and cultivation,soil texture are also important factors to soil acidification.5.The texture of most of the soil tested is silt loam.The average value of bulk density is 1.15 g cm^-3,the total porosity is 55.65%and the capillary porosity is 43.48%.These physical standards of soil are suitable for plants growing and the variation intensity is low. The average value of the air porosity is 12.81%.The air porosity of 33.34%soil samples is lower than 10%.The air porosity of soil is relatively low.The average aggregates content of wind drying soil is 80.44%that particle diameter is more than 0.25mm.The average water-stable aggregates content is only 22.29%and the average value of aggregates stability is 0.29.The quality and quantity of water-stable property of aggregates is bad.6.It affected plants growing as the depth of arable layer became lower and the depth of plow sole became deeper.The depth of arable layer range is between 7.5 and 25cm.The average value is 15.45cm.There are 49.09%soil samples which the depth of arable layer is less 15cm.Comparing with the data of the second soil general survey,the depth of arable layer decrease 2.36cm and the depth of plow sole increase 2.97cm.7.Soil integrate fertility of arable brown soil is evaluated by the method of using correlation coefficient to decide weight coefficient and the method of vague analysis, through selecting ten indexes which contributed a lot to soil fertility.The integrate fertility level of arable brown soil is moderate or more.There are no soil samples which fertility level is high（soil fertility integrate index is more than 0.8）.There are 50.00%soil samples which fertility level is moderate or more（soil fertility integrate index is between 0.6 and 0.8.）.There are 10.64%soil samples which index did not reach 0.5.The major factors that limiting soil fertility are imbalance of soil nutrient,relatively low potassium content,low organic matter content,relatively bad soil structure,not many stable aggregates,shallower arable layer,deeper plow sole,decreasing pH and apparent trend of soil acidification.更多还原