The practice turn "…ontologizing practices. Instead of bracketing conceptualizing, comparing, and classifying as belonging to theory-a domain exclusive of and dichotomous with that of practice-theorizing in general and conceptualizing in particular are conceived of as practices." (Kendig 2016: 3)

"Tracing how particular epistemological and methodological concepts have come into being" "Historicist thinking is the project of understanding the present through tracing the past" (Schickore 2011: 325, 327) Plant scientists usually use homogenous soil in experiments despite plants living in heterogenous soil.

The challenge of soil heterogeneity:

I am not taking this as physical heterogeneity only …

It is physical and biological heterogeneity together.

All the features of organisms are because of continuous-dynamic interaction with their environments

For example: All the features of these trees' olives are dependent on many factors-not only their genes but also factors such as temperature, light, soil properties, activities of other organisms: plants, animals, microorganisms …

All the physiological and evolutionary processes of plants (including how they respond to environmental changes and how they uptake nutrients from soil and use them for their survival and reproduction) depend on many factors in their environments-which are themselves processual-and how plants interact with those factors throughout their life cycles.

Image: Özlem Yilmaz Silverman

Soil is a crucial part of plants' environment Soil: water, soil particles and minerals, and various species of microorganisms, animals, and plants along with their activities/products and their decomposing remains.

Together, these constitute a system that is usually highly heterogenous, dynamic, and in constant change because of factors such as climate and the activities of organisms (humans being just one of these).

"There is some consensus now that the structural or morphological complexity of a system (biological or otherwise) is some function of the number of different parts it has and the irregularity of their arrangement …Thus, heterogeneous, elaborate, or patternless systems are complex. Order is the opposite of complexity …An ordered system has few different kinds of parts arranged in such a way that the pattern is easily specified. Homogeneous, redundant, or regular systems are ordered, such as the atoms in a crystal lattice or wallpaper patterns. " (1991;304-305).

Ordered = Organized (Organized systems can be complex-such as organisms!)

Structural and functional complexity Not surprisingly, this highly heterogenous and dynamic medium (soil) is at the center of control efforts in plant science. Soil heterogeneity is a concern in plant and agricultural sciences, and controlling soil is one of the most challenging parts of research that plant scientists have pursued during the last centuries.

Conceptualizations of plant-soil system, soil heterogeneity, and control Controlled Experiments:

"I consider experiments as forms of active inquiry, as interventions done by human agents who seek to gain knowledge about the world. On this view, controlled experiments can be provisionally characterized as interventions deliberately designed such that the effects of the experimental intervention become manifest to the human agent." (Schickore 2024).

"only if we examine how experimental control comes into being can we fully understand its role in experimental inquiry." (Schickore 2024).

"in the sense of a check or test observation or experiment," this usage is related to "the word control in its original meaning as a check or standard of comparison, a relatum"; (Boring 1954: 577).

Schickore notes that "comparison between the effects of an intervention in a particular situation and the same situation without the intervention" is "deepseated" and "traces of control measures" can be found in ancient texts (Schickore 2024: 32).

"as restraint or guidance," as applied to "keeping experimental conditions constant and also to altering the independent variable in accordance with precise known predetermination" (Boring 1954: 576).

There are various designs of experiments in plant sciences. One aspect of this variety is where the experiment is seti.e., growth chambers, greenhouses, fields

Image: Özlem Yilmaz Özlem Yilmaz Silverman, ISHPSSB 2025 Controlled experiments, intervention Different techniques of control in plant sciences Image: The Australian Plant Phenomics Facility Higher control More homogeneous medium Less control More heterogeneous medium

The problem of soil heterogeneity "Experimental control," as Schickore notes, "has a material-technical and a conceptual-epistemic side" (2024: 4).

Material-technical challenges include the development of various experimental methods to control soil with different techniques such as homogenizing, heating, dividing into pots, separating lines in the field, etc.

Conceptual-epistemic challenges can involve understanding plant-environment systems within the experiment conditions and integrating data from different experiments Hayes (1915) discusses the value of comparative research in breeding studies, which compare different varieties in order to investigate which ones are more resistant to parasites. He argues that further studies for standardizing methods of comparative trials are needed as soil heterogeneity and other environmental factors may interfere with trials.

Similarly, Harris (1915) notes that "A careful examination of the agricultural literature bearing on the question of variety tests will reveal many cases in which the experimenters have noted the difficulty of securing a uniform substratum, or in which there is internal evidence for the influence of substratum heterogeneity upon the result" [emphasis mine] (429).

Brenchley (1914) points to similar problems, noting that there have been controversies among scholars in her time about whether the compounds in question are toxic or stimulant for plants. She emphasizes that different growth substratum (soil, sand, and water) would bring about different results and that "a result obtained by one experimental method may apparently be contradicted by that obtained by another method" (283).

She also notes: "In soil cultures the supply of nutriment to the plant is quite out of control, and also the worker has no adequate conception of the interaction occurring between the soil constituents and the inorganic substances supplied for test purposes" [emphasis mine] (283).