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Soil museum curator Hsu Cheng-i travels all over Taiwan digging soil, delving deep into soil science and offering free consultations for farmers

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The most down-to-earth man! "Soil museum curator" Hsu Cheng-i travels all over Taiwan digging soil, delving deep into the great science of soil and offering free consultations for farmers

While others go around the island to challenge themselves, Hsu Cheng-i goes around the island to get to know the soils of all Taiwan. A professor in the Department of Agricultural Chemistry at National Taiwan University who grew up on a farm, he has spent his life studying soil surveys, and recently took over from his predecessor the Soil Museum that preserves soils from all over Taiwan, hoping to let more people truly understand Taiwan's "land."

Having traveled all over Taiwan and the world for more than twenty years, Hsu Cheng-i can be called the most down-to-earth man. Hsu Cheng-i says that soil not only provides for crop growth but is also closely tied to human life; from food to vessels, beauty and skincare products, the knowledge of soil is everywhere. Soil constitutes human civilization and also gives each place its unique "terroir."

Professor Hsu Cheng-i of the Department of Agricultural Chemistry at National Taiwan University (photo / Lin Yi-chun)

Taking over as the third-generation curator of the Soil Museum, guarding the research achievements of those before him

The gentle and refined Hsu Cheng-i is a true farmer's son, with his family home in Meishan, Chiayi. In soil science classes, the students below can always hear about his childhood days among orange trees. "I've had a close relationship with soil since I was little, but the key to deciding to go down this path was my mentor." The mentor he speaks of is Chen Tsun-hsien, a professor in the Department of Agricultural Chemistry at National Taiwan University who retired in 2017.

Hsu Cheng-i studied in the Department of Agricultural Chemistry at National Taiwan University, which at the time was divided into two tracks: soil and fertilizer, and agricultural products processing. He studied in the soil and fertilizer track. In his senior year he began researching together with Professor Chen Tsun-hsien. "At the time I had no grand ideas; I just decided to go down this path because my teacher said few people were doing soil surveys and it was a blue ocean."

That decision made him one of the few soil survey scholars in the country. Walking into the recently reorganized Soil Museum, Hsu Cheng-i explains that this museum is the accumulated soil survey results passed down through generations: his academic grandfather Chang Chung-min passed them to his mentor Chen Tsun-hsien, and he in turn took over from Chen Tsun-hsien, becoming the third-generation museum "curator."

Surveying around the island without shirking hardship, hiking while carrying heavy soil samples

In the museum you can see soil samples from all over Taiwan, from estuary alluvial plains, tropical tablelands to high-altitude mountain areas; some soil samples were even preserved from the Japanese colonial period. On the walls are many on-site photos from past soil surveys. "This is me during university, doing soil surveys together with Teacher Chen Tsun-hsien." In the photo, he and his present self have the same spirited look that has never changed.

Soil surveys are quite arduous work. Hsu Cheng-i says that the island-wide soil census in Taiwan began after 1960, and to this day, although the tools are slightly different, the survey methods have remained the same. "Some places are very remote; you need a four-wheel-drive vehicle and then walk to get there." He recalls once going to survey South Dawu Mountain, walking the Jinshuiying Historic Trail where annual rainfall exceeds 4,000 millimeters. The whole way was muddy; they set out at 2 p.m. and walked a full 4 hours, only arriving after dark.

"It's easy going up the mountain, but going down is even more tiring." Hsu Cheng-i says with a smile that on the way back they had to carry soil samples. If walking back, even when tired they did not dare sit down, "because after resting you'd have to stand up again carrying more than ten or twenty-some kilograms of luggage and soil samples." That was even more strenuous, so when everyone got tired they each found a tree or rock wall to lean against.

In 1992, Hsu Cheng-i (1st from right) conducting a soil survey with his mentor Chen Tsun-hsien (2nd from right) (photo provided / Hsu Cheng-i)

There are a great many soil survey tools, digging as deep as 2 meters

To do a good job, one must first sharpen one's tools. During soil surveys, all kinds of "equipment" must be brought along, including iron shovels or spades for digging, wooden frames and surface glue for making profile specimens, and the most eye-catching of all, the soil auger. The T-shaped soil auger can drill into the soil and extract soil samples from different depths; the auger can also be extended as needed, reaching up to 2 meters.

The first problem encountered in a soil survey is: "Where should we dig?" Hsu Cheng-i explains that soil is a natural body occupying volume on the surface, and over time it changes due to the action of plant and animal remains and climate. "Even within the same township, the soil quality may differ from east to west and north to south."

Therefore, exactly where to collect soil depends on the purpose of the survey. If it is a general census, then dense sampling must be done in the same area and carried out across multiple areas; if it is a survey of a specific region, then it is enough to collect some soil samples from that region. Researchers have drawn past survey results into a Taiwan soil map, divided from south to north and west to east into 11 colors, representing 11 soil orders.

Collecting soil profile samples requires digging from the soil surface down to the rock layer (photo provided / Yang Chia-yu)

Soil classification cannot be done by just grabbing a handful of soil; everything from the surface to the rock layer must be assessed

What is a "soil order"? Hsu Cheng-i says that soil order is the basic method of soil classification, just like kingdom, phylum, class, order, family, genus and species in biological classification. The classification method currently used worldwide is the United States' 12 soil orders classification. To be grouped into a particular soil order, there are many quantitative standards, such as color, texture, pH value and so on.

"When some people hear that I study soil, they grab a handful of soil in front of me and ask me about it, but actually that's very hard to answer," Hsu Cheng-i says with a smile, because what most people come into contact with is only the soil surface, and what they grab by hand is only a very tiny part of the soil. This is also why soil sampling needs to dig deep, sometimes even several meters deep. "A handful of sandy soil doesn't count as systematic classification; classification requires looking from the soil surface all the way to the parent rock."

Hsu Cheng-i takes out photos of past soil sampling to explain that the soil beneath the surface has a total of 6 layers, namely the OAEBCR layers. The top three layers are topsoil: the O layer is the litter layer, the A layer is the humus layer, and the E layer is the eluviation layer. Further down, the B layer is the illuviation layer, the C layer is the weathered layer, and the bottom R layer is the rock layer. "These layers are like a person's head, chest, waist, abdomen and feet. Just as a person must be looked at as a whole to make a diagnosis or analysis, so too with soil!"

So what are the classification standards? Do you look or do you touch? Hsu Cheng-i says that color, texture, particle size, water content, pH value and so on are all important indicators. Touching with the hand lets you feel whether it is sandy soil, loam or clay; the most intuitive is looking at color, which can be divided into red soil, yellow soil and black soil. Various indicators must be combined to classify. "Just saying black soil is very general; under black soil you also have to look at texture and composition, such as the black soil of Yangmingshan, which is volcanic ash, while the organic black soil bought at flower shops is peat soil accumulated from biological remains."

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