渭北旱塬土壤生化活性特征研究          下载免费PDF全文

谭向平  孔龙  和文祥 《西北农林科技大学学报(自然科学版)》2011,39(4):139-146

【目的】筛选能够表征土壤肥力水平的酶类和参数。【方法】采用非缓冲液法,对采自渭北旱塬陕西长武县农田19个土样的10项生化指标(转化酶、纤维素酶、淀粉酶、蛋白酶、脲酶、磷酸酶、过氧化氢酶、脱氢酶、尿酸盐酶和土壤呼吸强度)进行测定;并采用相关和主成分分析法,对土壤酶活性、土壤呼吸强度之间及其与土壤化学性质间的相关性和主成分综合得分进行评判;最后采用土壤酶总体酶活性参数(TEI、TEI5)对19个供试土样的肥力进行评价,并分析了其与土壤化学性质的相关性。【结果】土壤转化酶、脲酶、脱氢酶、土壤呼吸强度对土壤环境条件的改变较为敏感;10项土壤生化指标中,仅转化酶、脲酶、磷酸酶、脱氢酶活性和土壤呼吸强度之间及其与大多数理化性质间呈显著或极显著相关,揭示此5项生化指标与土壤化学性质关系密切,且在一定程度上可指示土壤肥力水平的高低;构建的总体酶活性参数TEI和TEI5,与土壤酶活性、土壤呼吸强度及土壤化学性质主成分分析获得的土壤肥力综合得分均达极显著正相关。【结论】土壤总体酶活性参数TEI和TEI5可作为表征土壤肥力的重要指标,并能反映土壤整体酶活性和呼吸强度的高低。  相似文献   

柚子园主要土壤肥力属性空间变异及合理取样数研究   总被引：2，自引：0，他引：2  

李柳霞  沈方科  赵凤芝  黄景  郭志荣  顾明华 《广西农业科学》2007,38(4):433-436

对柳州市一个面积约20hm2的柚子园采用50m×50m网格取样,布设76个采样点,对土壤pH、有机质、碱解氮、速效磷、速效钾的空间变异性及合理取样数作初步研究。结果表明,该柚子园土壤pH、有机质以及大量营养元素含量变异系数范围为6.45%~59.48%。地统计分析表明,这些土壤肥力属性均在一定范围内存在空间相关性,土壤速效钾的空间相关性弱,而有机质、碱解氮具有中等的空间相关性,土壤pH、速效磷空间相关性强。同时探讨了研究区域土壤的pH值、有机质和大量营养元素的合理取样数,结果显示,在95%置信水平下,土壤碱解氮选用5%的相对误差,土壤pH选用10%的相对误差,其余指标选用15%的相对误差水平,土壤pH、有机质、碱解氮、速效磷、速效钾的推荐取样数分别为2、6、34、28、35个。  相似文献   

Feasibility of Site-Specific Management of Corn Hybrids and Plant Densities in the Great Plains     

Shanahan  John F.  Doerge  Thomas A.  Johnson  Jerry J.  Vigil  Merle F. 《Precision Agriculture》2004,5(3):207-225

The goal of this research was to determine the potential for use of site-specific management of corn hybrids and plant densities in dryland landscapes of the Great Plains by determining (1) within-field yield variation, (2) yield response of different hybrids and plant densities to variability, and (3) landscape attributes associated with yield variation. This work was conducted on three adjacent fields in eastern Colorado during the 1997, -98, and -99 seasons. Treatments consisted of a combination of two hybrids (early and late maturity) and four plant densities (24,692, 37,037, 49,382 and 61,727 plants ha^-1) seeded in replicated long strips. At maturity, yield was measured with a yield-mapping combine. Nine landscape attributes including elevation, slope, soil brightness (SB) (red, green, and blue bands of image), EC_a (shallow and deep readings), pH, and soil organic matter (SOM) were also assessed. An analysis of treatment yields and landscape data, to assess for spatial dependency, along with semi variance analysis, and block kriging were used to produce kriged layers (10 m grids). Linear correlation and multiple linear regression analysis were used to determine associations between kriged average yields and landscape attributes. Yield monitor data revealed considerable variability in the three fields, with average yields ranging from 5.43 to 6.39 Mg ha^-1 and CVs ranging from 20% to 29%. Hybrids responded similarly to field variation while plant densities responded differentially. Economically optimum plant densities changed by around 5000 plants ha^-1 between high and low-yielding field areas, producing a potential savings in seed costs of $6.25 ha^-1. Variability in yield across the three landscapes was highly associated with landscape attributes, especially elevation and SB, with various combinations of landscape attributes accounting for 47%, 95%, and 76% of the spatial variability in grain yields for the 1997, -98, and -99 sites, respectively. Our results suggest site-specific management of plant densities may be feasible.  相似文献   

云南稻品种与普通稻品种杂交后代的遗传变异     

罗利军  张端品  谢岳峰 《华中农业大学学报》1988,(2)

用云南稻品种(籼粳各二)与普通稻品种(籼粳各一)杂交,其F_2的抽穗期、单株有效穗、株高、主穗总粒数、结实率和百粒重六性状均出现了广泛的分离,从中可以选择出综合性状较好的个体。  相似文献   

马尾松种源胸径生长的空间异质性   总被引：1，自引：0，他引：1  

陈美高 《福建林学院学报》2005,25(4):333-337

在福建省大田桃源国有林场开展91个马尾松种源造林试验,选择全国马尾松种源中具代表性的43个种源胸径生长资料,采用二元线性方程及地统计学方法研究马尾松胸径生长的空间异质性规律.结果表明,43个马尾松种源在纬度和经度上的二维空间异质性规律较明显,地统计学方法分析马尾松胸径生长的空间异质性效果比一次数学模型拟合效果更优,拟合优度达99.99%,是模拟马尾松生长的空间异质性的理想模式,从而为马尾松优良种源选择提供了理论依据.  相似文献   

涝渍地土壤主要肥力因子空间变异特征研究     

龚绍琦  沈润平  金卫斌  艾天成  李敏 《江西农业大学学报》2003,25(5):720-724

利用地统计学的方法，以湖北三湖农场为例，研究了涝渍地土壤有机质、碱解氮、速效磷和速效钾等4种主要肥力因子的空问变异规律，结果表明：土壤肥力因子的分布具有明显的空间变异特性，碱解氮变程最小为l740m，有机质其次，为2200m，速效磷和速效钾分别为58560m和8060m。土壤有机质的空问变异受结构性因素影响较大，具有强烈的空问相关性；而碱解氮、速效磷和速效钾的空间变异是由结构性因素和随机性因素共同作用引起的，属于中等的空问相关性。在此基础上，应用克里格法进行空问局部内插，绘制出4种土壤肥力因子的分布图。  相似文献   

典型草原普通栗钙土土壤湿度空间变异的初步研究     

佟乌云  李绍良  贾树海  王芳玖  陈有君 《中国农业大学学报》1997,(Z1)

在一块面积为60m×60m 的样地上用重复距离倍增的方法布置了72个取样点,初步研究了草原地区普通栗钙土(暗栗钙土)湿度的空间变异及相关特性。结果表明,在天然植被覆盖下的暗栗钙土,浅层的土壤湿度大,其变异程度也较高,计算平均含水量的土层越厚,则相对变异程度越小。各层土含水量的统计特征都遵循正态分布。浅层相关距离较短,多层平均含水量的相关距离近于各层相关距离的平均值。  相似文献   

The “Null Hypothesis” of Precision Agriculture Management     

Whelan  B. M.  McBratney  A. B. 《Precision Agriculture》2000,2(3):265-279

As precision agriculture strives to improve the management of agricultural industries, the importance of scientific validation must not be forgotten. Eventually, the improvement that is imparted by precision agriculture management must be considered in terms of profitability and environmental impact (both short and long term). As one form of precision agriculture, we consider site-specific crop management to be defined as: Matching resource application and agronomic practices with soil and crop requirements as they vary in space and time within a field. While the technological tools associated with precision agriculture may be most obvious, the fundamental concept will stand or fall on the basis of scientific experimentation and assessment. Crucial then to scientifically validating the concept of site-specific crop management is the proposal and testing of the null hypothesis of precision agriculture, i.e. Given the large temporal variation evident in crop yield relative to the scale of a single field, then the optimal risk aversion strategy is uniform management. The spatial and temporal variability of important crop and soil parameters is considered and their quantification for a crop field is shown to be important to subsequent experimentation and agronomic management. The philosophy of precision agriculture is explored and experimental designs for Precision agriculture are presented that can be employed in attempts to refute the proposed null hypothesis.  相似文献   

渗透系数的空间变异研究     

李金荣  韩新正  万红友  于鲁冀  杨振放  刘宝 《中国农村水利水电》2011,(2)

用区域化变量理论和半方差函数研究测试区含水介质的渗透系数,研究结果表明含水介质的渗透系数具有空间变异性,属于中等程度变异.通过对其半方差函授进行拟合,其E-W方向的变异程度主要由含水介质本身的空间结构引起.S-N向含水介质的渗透系数其空间变异程度主要由随机性引起.  相似文献   

基于GIS和地统计学的张掖市甘州区土壤全氮、有机质的空间变异特征分析   总被引：8，自引：1，他引：7  

杨东  刘强 《土壤通报》2011,(3):593-597

区域的土壤是一个形态和过程相当复杂的自然综合体,成土过程中受到多种因素的影响,使得土壤性质具有高度的空间异质性。以甘州区土壤(0~20 cm)中全氮、有机质为研究对象,运用GIS和地统计相结合的方法研究了土壤中全氮、有机质的空间分布特征,并用经典统计方法分析获取土壤基本属性的特点,并随后用普通克立格插值的方法绘制了土壤全氮、有机质的空间分布图,发现甘州区土壤全氮、有机质含量比较低,存在着明显的空间分异性,表现为从中心向四周逐渐递减的趋势。  相似文献