Ecological Agriculture

By Li Ziyue (Yunnan Eco-Health Programme Officer)

Every plant has its own form of intelligence related to survival. Do humans in modern society overemphasise modifying agro-ecosystems to maximise production, whilst ignoring plants’ own abilities for intelligent self-improvement? The existence of every plant species is a legend. How can humans sustain these legends, and maintain the mutual relationships among species, in order to retain a stable network of lives ?

On July 18–20, PCD’s Yunnan Team was honoured to have Mr Kuang Haiou, a honeybee expert from Yunnan Agricultural University, and Mr Cheng Geng, a wheat expert at Yunnan Academy of Agricultural Science, to facilitate the “Agro-ecosystem Experiential Workshop” that took place at Haibaoqing Organic Farm. We had been to the farm several times and were familiar with its ecological landscape and environment. However, when we got up close with its systems of innumerable living things, it felt so unfamiliar and we had to start all over again to get to know it. Accompanied by experts and all the living things of Haibaoqing, we “entered” the life cycle of fruit trees, vegetables, insects (honey bees, butterflies, ants etc.) and weeds. We looked, touched and felt them with close attention, exploring the meaning of their lives and reflecting on how we might build more stable agro-ecosystems.

When we returned to Haibaoqing Organic Farm, the trees were still green as though they had forgotten it was already late autumn. The flowers were still fragrant and blooming, attracting the attention of honey bees. Butterflies were waltzing in the field of Garland Chrysanthemum, which were bewitching innumerable insects with their beautiful dance and drawing our gaze to them too. Accompanying us on our voyage of learning were Kuang Haioi the bee expert’s many alluring stories of life that helped us gain a completely new understanding of plants, insects and soil—knowledge that shook and rocked our way of thinking.

From natural ecosystem to agro-ecosystem

In a natural ecosystem, there are different species of living things. The same species of living things form a population, and various populations form a community or biocenosis. The natural ecosystem is thus formed by various biocenoses [and their physical environment]. Between these biocenoses there is constant cycling of material and flow of energy, which gradually reaches a dynamic balance and enables the ecosystem to attain relative stability, and have a capacity for recuperation. However, agro-ecosystems often suffer from human intervention and the pressure to meet human needs. The food demand is often more than the system’s production capacity. As a result, the laws of an agro-ecosystem may be distorted. Because of the excessive pursuit of production and other economic and political considerations, the diversity of species is reduced. Continued export of resources from an agro-ecosystem will upset its cycling mechanisms, making the ecosystem more unstable.

To feel and to learn about the life of plants and the network of lives

In the workshop, our imagination was aroused by knowledge of the capacity of plants for recuperation and their intelligence, and we learnt to appreciate the incredible processes and changes in the life of plants. For example:

1. Plants’ capacity for recuperation: Because of plants’ own metabolism and self-healing power, when a plant (such as a tree) is cut, its bark will excrete a large amount of endogenous hormone in a short time. New shoots or new roots will grow and the plant will begin a new life.
2. The intelligence of wheat: Waxy powder on the leaves of wheat can prevent insects from biting and eating the leaves, and help the plant to resist frost. When a wheat leaf suffers from external attack such as an insect bite, a liquid membrane will be formed on the surface of the wound which will spread out on the leaf and stop insects from biting it again. It also helps the wound to heal and protects it from bacterial attack. Meanwhile wheat awns help the plant from being eaten by birds and insects, so as to protect the growth of kernels.
3. The intelligence of potatoes: A starchy tuberous crop, potatoes also flower and bear fruits. The main purpose of a potato’s life is to generate offspring. A potato plant generates genetically identical offspring through its tuber while its genetically diversified offspring grow from the seeds of its fruits. When its tuber has not grown well and fails to become a seed potato, the plant will bear fruits and ensures it has offspring.
4. The intelligence of xiaogua ^[2](zucchini/courgette): When a zucchini fails to grow, the plant will cut its nutrient supply. The zucchini fruit will then turn into food for microorganisms which will break down the organic material for the plant’s own need. When a leaf of the plant is partially eaten by insects, the plant will also stop providing nutrients to it and the tissue around it would die. In this way, the plant protects itself from secondary bacterial attack.

Overturning our perceptions of weeds and pests

Weeds are the ancestors of many crops. We must not forget the ancestors of vegetables that nurture us. The word “weeds” is only a conceptual definition by human beings. People call all plants we don’t use “weeds”, but weeds actually have their specific function and value in an agro-ecosystem. For example:

1. Weeds in spinach fields: They conserve sunlight, water and soil, and prevent excessive fertilizer from draining off. They also provide the habitat and food for insects.
2. Weeds in maize fields: When there is no weed in a maize field, earthworms will eat the roots of the maize. However, earthworms may instead eat the roots of weeds if available. Weeds also absorb sunlight, conserve energy and provide shade to the earth and so conserve water inside soil.

Insects should also not be classified into good or bad. Though some insect larvae eat crop leaves, when they become adult insects then they will help plant pollination. Insects in the fields usually eat parts of a plant but not the whole plant. They also choose plants close to them instead of going all over the field to search for food. When there are weeds around an agricultural field, fewer insects will feed on vegetables. By cultivating diverse plants (including weeds), vegetables will suffer less from pests and disease problem.

Reflection on domestication

Domestication means turning wild species of living things into cultivated plants or reared animals to meet human needs and purposes. For example, members of the Brassicaceae vegetable family, which we eat everyday, have been domesticated for a long time. They may have their own intelligence and strategy for survival (generating offspring). Are they completely under the will and control of human beings? Or do they have their own intelligence that guides their survival adaptation? Should we, conversely, start to wonder whether human taste is being cultivated by the large Brassicaceae family? These questions make us wonder what role human beings should play in the agro-ecosystem, and how we should redefine our roles.

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During the workshop, we gained a new understanding of the value of different lives in an agro-ecosystem.	While experiencing the harvesting of potatoes, we learned that even digging a small piece of land will create an impact on the whole agro-ecosystem, and that different lives are connected.	Our understanding of “weeds” was overturned when we learned about their ecological functions.
Discussing the domestication relationship between Brassicaceae vegetables and humans, we were inspired to reflect on the human role in an agro- ecosystem.	Though they are small, honey bees play an incredibly important role in agro-ecosystems.

1. An agro-ecosystem is an organic system in a specific time and space developed by human beings, making use of the interactions between agricultural organisms and their environment, as well as interactions among different species. As in a natural ecosystem, living organisms in an agro-ecosystem can be divided into “producers” which are dominated by green plants, “consumers” which are dominated by animals and “decomposers” dominated by microorganisms.
2. In Yunnan, zucchini is known as xiaogua and in Hong Kong it is known as cuiyugua.