Jakob Marteen Van Bemmelen (1830-1911) was a chemist from the University of Leiden in the Netherlands. He is known in soil science for the van Bemmelen factor, a conversion factor for soil organic matter to carbon: Soil OM = 1.724 * Soil OC.
The publication that refers to this factor is:
Van Bemmelen, J.M., 1890. Über die Bestimmung des Wassers, des Humus, des Schwefels, der in den colloïdalen Silikaten gebundenen Kieselsäure, des Mangans u. s. w. im Ackerboden. Die Landwirthschaftlichen Versuchs-Stationen 37, 279-290.
Van Bemmelen did not derive this factor; in the publication, 1.724 was called the von Wolff factor. The soil used in this publication is a volcanic soil from Deli with 5% humus (page 283) with 2.94% C.
So why Van Bemmelen used the soil from Deli? JM had studied volcanic soil from Deli and Malang and alluvial soil from Rembang for tobacco cultivation.
Van Bemmelen, J.M., 1890. Die Zusammensetzung des vulkanischen Bodens in Deli (Sumatra) und in Malang (Java), und des Fluss-Thonbodens in Rembang (Java), welche für die Tabakskultur benutzt werden. Landwirtsch Versuchsstat 37: 257; Kon Akad v Wetensch 25 Jan. 1890
He described the soil from Deli as: “The volcanic clay is heavy and light consistency. In the coastal area, it is gray in color, e.g. soil in Medan 15— 50 m above the sea. This is now highly appreciated. In the higher elevation areas (60-150 m) is a reddish-brown clay or loam, which too is very fertile and used to be considered the best (e.g. in the department of Mariendal, in Deli Toewan)”
The soil in Deli had been growing tobacco for more than 20 years when JM started to work on it (in 1889). Deli tobacco is famous for its quality and used as an expensive cigar wrapper, highly-priced in Europe since the colonial time and until now. In Experiment Station Record, it was recorded that there was a problem of a decline in tobacco productivity in Deli. Soil samples were sent to Holland and Germany and fertilizer dealers offered various products, but they appeared to be useless. JM van Bemmelen was asked to investigate this problem and wrote a report:
Van Bemmelen J M (1890) Ueber die Ursachen der Fruchtbarkeit des Urwaldbodens in Deli (Sumatra) und Java für die Tabakscultur, und der Abnahme dieser Fruchtbarkeit. Landwirtsch Versuchsstat 37: 374
The tobacco itself is only grown for 40 days. The volcanic soil from Toba tuff in Deli apparently was very fertile when it was cleared and produced high-quality tobacco leaves. However, after several years the tobacco yield declined. van Bemmelen did an elemental analysis of the soil and found that the soil condition had declined. He attributed the fertility of the forest soil to the thick humus layer.
“The humus, the loose physical constitution, and the peculiar composition of weathering silicate are undoubtedly very important moments for conservation the right moisture content, and for the nutrition of plants through the proliferating roots and fast growth of the leaves”
However, after 7 or 8 years of cropping the soil became depleted, the nature of the soil is not yet the same as that of the fresh forest floor. “The second and subsequent tobacco harvest,” says Fritz Reuter, an administrator of the oldest Deli company, “can’t even remotely be compared with her predecessor on the same but wood-covered soil; even repeated and deeper tjankollen (cangkul or tilled) with simultaneous application of Guano is unable to compensate for this difference fully. “
To solve this problem, he recommended restoring the humus floor. After harvest, the soil is left fallowed, which will then be occupied by alang, shrubs and then trees. “Tigers, snakes, wild pigs inhabit the forest again.” “After 5-10 years the forest floor is back to the old one, good condition – physically and chemically will return, and treated the same way, can produce the same tobacco as the first time.”
Thus the recommended practice in Deli is tobacco is grown for 2 years and then left for 6 to 8 years to be afforested.
It seems that van Bemmelen through his analysis of humus in the soil realised the importance of maintaining soil organic matter (or humus floor) which create well structured soil.
“If you want this fine variety of tobacco, good quality color, creamy and flammable, then you need a temporary restoration of the forest in the first place. Just applying chemical fertilizers attempted by the planters is practically useless.”
JM concluded:
When scientific studies and crop experiments should benefit the tobacco culture if you want to find the causes why the tobacco culture in other parts of East Sumatra, e.g. B. in Siak), has only given losses, so these examinations must take place at an experimental station set up in Deli, under the direction of an efficient agricultural chemist who has already proven by previous work, that he can understand and solve scientific questions. However, he has to work entirely free and not be obliged to make new discoveries at certain times, or to get beneficial results – at the risk that the station will otherwise be compromised. An exact and genuinely scientific study of the training of the tobacco plant in this area, the metabolism in the same in the various stages of their development, and the soil conditions, as well as a critical gathering of all the experiences made on a large scale, all of this has to be calmly put into work be unconcerned whether these investigations make it profitable for culture in less time. You must initially be satisfied with the hope that strict scientific research always, sooner or later, bring out new and useful things for the culture.
One has to be convinced that it is the only true foundation form to the raw empirical through a rational culture that cannot be replaced, which is an ever-increasing certainty of success granted. Only scientific investigation can do that, explore the true context of the appearances in their necessity; a rational culture must focus only on this support.
Leiden, December 1, 1889.
Soil at Bulu Cina in Deli for tobacco. It is volcanic derived materials in between two rivers: Sungai Ular & Sei Wampu.
We were at the Deli tobacco field in Bulu Cina early this year, and the same recommendation is still being practiced. Except now it was grown for 1 year and rotated with sugar cane for 2-4 years. The main reason is to break the tobacco disease cycle. Soil carbon in the soil has now declined to 1%.
It seems that JM had never been to Indonesia, and only analysed samples provided to him. The son of JM, Willem van Bemmelen (1868–1941) was a geophysicist who was transferred to work in the Royal Magnetical, Meteorological, and Seismological Observatory in Batavia in 1898. He later became the director of the observatory. Willem’s son (JM’s grandson) Reinout Willem van Bemmelen was born in Batavia (1904-1983), and became a geologist who wrote The Geology of Indonesia. Rein is known for his theory on Batak Tumor on the formation of Toba cauldron.
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