3. Evaluation Method for Quality of Crop and Ecosystem

In this article

3-1. Relationship Between Crop Taste and Fertilizer

In traditional agriculture, the fertilizer heavily influences the taste of the produce. For example, organic fertilizers contain minerals, which add a characteristic mineral flavor to the vegetables. However, this is a taste derived from artificially applied fertilizer that is qualitatively different from an intrinsic taste of the crop.

As we continue to practice Synecoculture, the soil will gradually be composed of only elements that are a part of the self-organized material circulation of the ecosystem, and be in a state where there is no artificial surplus.Promoting natural circulation stabilizes various unstable elements or makes them harmless, reduces adverse effects on neighboring ecosystems, and constantly reorganizes material composition and distribution in a way that globally promotes biodiversity. Soil developed under such process is what makes the spring water drinkable (for example in primeval forests in mountains, etc.), as the water passes through the elaborate soil structure, which we idiomatically call as “clear soil.”Clear soil has already been formed in areas that have been left to nature, however, for areas where inorganic fertilizer was used as in modern farming methods, it will take several years to create clear soil. For areas with organic farming, we estimate that it will take at least 8 years if organic fertilizer was deeply mixed into the soil. Even during the transition from other farming methods to Synecoculture, vegetables with vitality can be obtained. However, the metabolic state and consequently the taste will be influenced by the soil residue. Once clear soil is achieved through Synecoculture, the taste of the vegetables will be of a different quality ( clear taste ) from organic ones.

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In organic farming, there are many practices to plow organic fertilizer (decomposing organic matter) into the soil. If there is too much undecomposed organic matter or if it is incorporated too deeply, it exceeds the amount soil microorganisms can decompose annually, leading to decay that cannot be utilized as fertilizer. Fully decomposed and stabilized compost does not decay in the soil, but applying large amounts to tilled soil causes excess nutrients to leach into groundwater, impacting water systems. Additionally, there is a high risk of antibiotic contamination for the livestock waste of cows, pigs, birds, etc. In contrast to all these negative effects of human intervention, unmanaged, abandoned farmlands promote the recovery process of clear soil. Organic materials do not get too deeply underground in the natural state, with the sole exception of natural disasters. Such example is crude oil that is considered to have been transformed from organic matters over years deep in the ground.

Clear taste vegetables : carrots that take on the flavor of Japanese persimmon, cabbage with a sweet core, broccoli and asparagus that can be eaten raw to the stalk, etc.

3-2. Pest Outbreak

Pests refer to a large outbreak of insect species that have harmful effects for agriculture. Although many insect species are designated as pests in conventional farming methods, they do not multiply to the point of causing serious damage to production in Synecoculture: They are controlled by the elaborate food chain in the plot and the surrounding environment. They can rather take on the tasks of essential ecosystem functions similar to other useful insects, such as pollination and stimulate vegetative regeneration. Synecoculture should be achieving a state where the vegetation is controlled in a manner that the benefits of insect fauna outweigh the losses, and where no single species will emerge as a dominant pest. This is common with the primeval forests of mountains, where little pest occurs under the dominance of single species as the degree of species mixing is high.

Plants take on the role of a “purification device” in the ecosystem, spitting out unnecessary materials from the soil. In the process of absorbing surplus components, the vegetation tends to be monotonous, and there’s high risk of insects eating that vegetation to outbreak massively. In conventional farming methods, fertilization, single-species cultivation, plowing and pesticides destroy the food chain and create the background of a pest outbreak. Excess materials in the soil, such as leftover compost, are the ecological cause behind the loss of faunal balance expressed as a pest. Empirically, pest risk is reduced in soil that has been purified through the promotion of natural circulation.

If there were a mass outbreak of a single insect species during the implementation process of Synecoculture, it would be possible that the soil is at the stage where it needs to be purified. Rather than exterminating, we should facilitate the removal of the surplus materials by the insects.

If there is damage due to external factors such as invasion of non-native species, we recommend diversifying the vegetation in order to further diversify the food chain to regain faunal equilibrium.

3−3. Soil Improvement

Soil improvement in Synecoculture is carried out in the course of natural circulation and vegetation transition by using the plants and vegetables, without using any soil improvement materials.

However, for physical components that are independent from the biological and chemical disposition, they can be freely changed during the initial construction phase: For example, soil texture decides the capacity of organic matter retained by the topsoil in a given climate condition, which can be freely adjusted in the initial setup.

If dealing with hardened soil where the recovery of the natural circulation and vegetation transition processes is too slow, such as conversion from residential land, it is possible to freely enact initial soil improvement measures. However it will require a transition period to Synecoculture until clear soil can be realized.

For example, soil improvement in the initial construction is possible through moving plant organic matter derived from nature, such as cut grass from the surroundings, and promoting decomposition using microbial materials. However cultivation through continuous and fixed usage of microbial and organic materials from external sources, is a violation of Synecoculture principles.

Regarding chemical properties, it is possible to introduce adjusting method as long as it does not hinder natural circulation, and it will not be necessary to continually introduce external materials: For example, placing oyster shells on the surface during initial soil improvement will serve for pH adjustment.

If the vegetation is scarce, one method is to claw the surface first and then deliberately grow thick weeds, or plant fast-growing trees to construct the ecosystem regardless of its usage, however the most ideal method is to realize these functionality with useful plants.

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Examples of soil texture improvement: Overlay/mix into the field river sand and clay that does not contain organic material.

For vegetation recovery in wastelands where vegetables do not grow, sow mainly Asteraceae vegetables such as lettuce and chicory, and mix in root vegetables in an appropriate level. Asteraceae vegetables can be raised even in pebble-filled wastelands.Wildflowers that can be used in tea, such as horsetail and chameleon plant, are also effective in soil improvement, and suppresses grass weeds. Strong woodland fruits such as persimmon, loquat, citrus fruits, blueberries; strong trees such as common figs, mulberry; shrubs and perennial plants such as mountain asparagus, ashitaba can also suppress weeds. Another method is to plant tall trees early, and then thin them out as other vegetation grows accordingly.

If you are concerned about leftover fertilizer from conventional or organic farming used in the previous iteration, one method involves using wild oats and rye to suck in and expel, to purify the soil.

3-4. Plant Tissue Normalcy

In Synecoculture, as a preliminary criterion before the crop taste and nutrients, the plant tissue normalcy is evaluated with respect to the ecological optimum state as a standard. The fresh allure of sane plant tissue is sometimes idiomatically referred to as vitality of plant. The most practical and simple method for determining plant tissue normalcy is the “clear taste” when eaten raw, which describes a particular quality of flavor common in Synecoculture produce based on empirical expressions. However when determining the clear taste, it will be necessary to have comparative experience between Synecoculture and conventional farming produce.

There have been reports of health improvements from those who consume produce that cleared the strict standards for Synecoculture, even when consuming regular vegetable types [Funahashi 2025] . As a supportive evidence of health beneficial effect, compared to conventional produce, Synecoculture produce is revealed to contain rich secondary metabolites, which is the largest source of medicinal ingredients [Ohta et al. 2020] [Ohta 2023] .

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Though “clear taste” is a subjective expression, since it is a characteristic that is commonly and repeatedly experienced when eating raw vegetables from an ecological optimum state, evaluation is possible such as using food sensory analysis together with the assessment of the cultivation conditions.

From consumers’ health improvement cases, the positive relationship between the normalization of plant tissue and the normalization of human metabolism has been speculated.

3-5. Structure and Fluctuations

The concept for natural circulation in Synecoculture is qualitatively divided into structure and fluctuations:

The structure is the establishment of the natural circulation, on which human shall not intervene. In contrast, the fluctuations are the variability within the structure, which vary in accordance to environmental conditions. Human intervention may be allowed as long as it remains in the variation range of the natural circulation.

3-5-1. Examples of Structure

Soil structure that is realized in a competing symbiotic state (ecological optimum state) of planting:

Plowing that destroys the soil structure is regarded as an intervention to the structure, and is not allowed.

Even without plowing, removing all the weeds and exposing the topsoil means losing the roots that form the soil structure, so removing all weeds is considered to be an intervention to the structure. Regular installation of vinyl mulch acts as an obstruction to the soil structure formation, and is considered to be an intervention to the structure.

Traffic of Fauna, Material Circulation:

Starting with insects and birds, animals freely come in and go out of the Synecoculture plantation. As trace elements are supplied through diffusion by these fauna, their traffic must not be disturbed. Additionally, an open-field environment that is not disconnected from rainwater and groundwater is necessary to establish material circulation.

Therefore, the use of agricultural chemicals such as pesticides, using a plastic greenhouse to completely shut out insects and rain, and an indoor environment that cuts off the connection with underground water does not constitute Synecoculture.

However, using only the skeleton of the plastic greenhouse or the walls with no ceiling, or using fences to keep out mammalian pest such as wild boars, monkeys, deer, and other harmful beasts, is allowed as long as it doesn’t interfere with the coming and going of most other insects and animals.

3-5-2. Examples of Fluctuations

Amount of sunlight:

As there exists rock and tree shade even in a natural state, the changes in sunlight from the surrounding buildings and trees is within the range of fluctuation.However, no sunshine will result in no growth, and too much sunlight creates an environment that’s advantageous for indigenous weeds. During germination, the use of cheesecloth, etc., to control the sunlight partially or short-term is acceptable.

Amount of water:

Precipitation varies significantly even within a single day and exhibits seasonal and annual fluctuations. Therefore, artificial irrigation during periods of low precipitation falls within the range of these fluctuations. However an excess of water leads to vegetable blistering and deviates from plant tissue normalcy.

Amount of seeds and seedlings and planting period:

As the amount of seeds in the natural state changes in accordance to the surrounding vegetation and seed bank, humans introducing seeds and seedlings for the purpose of controlling the vegetation strategy is within the range of fluctuation.

For the germination and establishment of plants, as there are fluctuations in the environmental conditions and individual differences in nature, time-selective planting of seeds and seedlings by humans as part of vegetation strategy is considered to be in the range of fluctuation.

From the point of view of ecological optimum in Synecoculture, seeds and seedlings introduced by humans correspond to the initial condition setting to establish mixed vegetation toward ecological optimum, serving as an active intervention method that promotes the self-organization of augmented ecosystems [Funahashi 2025] .

Naturally occurring vegetable organic matter on top of soil:

If the soil structure is formed, piling up naturally occurring vegetable organic matter such as mowed grass from the surroundings on top of the soil, or conversely removing mowed grass, these are considered to be within the range of fluctuation. It does not interfere with the maintenance of the soil structure nor causes the contamination of groundwater.

Other hyper-diluted amounts of active agents:

Naturally occurring active agents and natural pesticides that are hyper-diluted in homeopathic dose is practically out of concern of material cycle, however it will be necessary to make an objective assessment on that effect. It is best to not utilize any useless materials.

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The problem of invasive non-native species has been spreading along with modern agriculture. The non-native species introduced by humans largely influences the ecosystem, including the material circulation level, and is involved with the structure. However, the various mixes of useful plants that are enacted through Synecoculture restrain the dominance of non-native species, create various material circulations similar to indigenous ecosystems, and we expect that will mitigate the adverse effects of alien species.