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土壤耕性是指与植物生长和耕作效果有关的一种概念。它主要由土壤结构和结持度所决定,此二者虽由聚合程度、分散率、阿特伯和米田结持常数等多种指标来表示,但仍定义得含糊不清。本项研究的目的在于求得一个可用作土壤耕性定量标准的复合特性,并进一步根据田间观察性状预测定量耕性指标。在本项研究中,对一组被认为是与结持构或结持度有关的十个变量进行了因子分析。对任一层次的样本均一致得出两个相同的基本因子;一个与腐殖质、容重(BD)、孔隙度(PORE)、塑限(PL)及分散率高度相关,另一个与土壤质地、粘粒和砂、粘结力、极限破碎强度(UBS)和自然破碎强度高度相关。第一个因子与结构密切相关,因此称为“结构指标”。第二个因子似乎是土壤结持度的重要部份,并叫做“结持度指标”。这两个指标是相互独立的,且比通常的结构和结持度概念含义更为精确。此外,它们明显优于用作这两个物理性状指标的单个变量,因为它们是从那些单个变量里选取出来的复合特性。在本研究的第二部分,我们将在这两个指标的基础上推导出土壤耕性的数值标准。
Soil tillage refers to a concept related to plant growth and tillage effects. It is mainly determined by the structure of the soil and the degree of endurance. Although the two are expressed by various indicators such as the degree of polymerization, the dispersion rate, the constant of Arte and Nakata, it is still unclearly defined. The purpose of this study was to find a composite characteristic that could be used as a quantitative criterion for soil tillage and to predict quantitative tillage indices based on field observations. In this study, a set of ten variables that are considered to be related to the structure or outcome of a knot has been subjected to a factor analysis. Two identical basic factors were obtained consistently for each level of sample; one was highly correlated with humus, bulk density (BD), porosity (PORE), plastic limit (PL) and dispersion, and the other was related to soil texture Granules and sand, adhesion, ultimate crushing strength (UBS) and natural crushing strength are highly correlated. The first factor is closely related to the structure and is therefore called the “structural indicator.” The second factor seems to be an important part of soil hold-up and is called the “end of life indicator.” These two indicators are independent and more precise than the usual concept of structure and balance. In addition, they are clearly superior to the single variables that serve as indicators of both physical traits, since they are compound features that are taken from those individual variables. In the second part of this study, we will derive numerical criteria for soil plowability based on these two indicators.