Agroecological Farming Systems in China 213cultivated between mulberry, the space can be fully utilized, while the fertility of
the soil can be improved. However, the intercropping of mulberry with maize and
sorgum or millet will be harmful to the soil. Radish can be grown within 60cm of
the trees. When the radish are harvested, pigs can be put in to feed on the residues
of crops and to loosen the soil. Jia Sixie affirmed the role of green manure in soil
improvement, and suggested that the best way is to plough in mung beans, then
lesser beans and sesame. In brief, Qi Min Yao Shu is not only rich in content, it is
detailed and accurate. It sums up the vast amount of agricultural knowledge accu-
mulated in China before the 6th century, with a deep understanding of the inter-
relationship between crops and their environment and implementation of the
knowledge in agricultural practice.
China is the country which first raised silkworms, planted mulberry trees and
wove the wonderful silk fabric. Silk culture existed in China 4000 years ago, the
embryo of IFS had appeared in the Shang–Zhou period (1600–1100 BC), and
records of the Han Dynasty (206 BC– AD 220) mention sericulture in the Can Shu
(Books on Silkworm Raising) and Zhong Shu Cang Guo Xiang Can (How to Plant
Trees, Store Fruits and Judge Silkworm). Unfortunately, none of these has come
down to us. In the more than 2000 years since the Han Dynasty, however, a
number of ancient books discussing sericulture have been handed down. Some are
monographs; others devote chapters to sericulture. In the techniques of sericul-
ture, not only the integration of mulberry cultivation with silkworm raising was
included, but the methods of cultivation of different types of mulberry in coop-
eration with other plants. For instance, Fan Sheng Zhi Shu tells how to grow mul-
berry trees: ‘In the first year, sow a mixture of mulberry seeds and glutinous millet.
When the mulberry plants are as high as the millet, cut them down with a sickle
close to the ground. Next spring mulberry suckers will spring out. Such mulberry
trees are convenient for plucking and management because of their shortness.’
Through continuous efforts and improvement by farmers in different periods,
sericulture, together with animal husbandry or fishery, has become the major ‘side-
line’ production in the self-sufficient rural economy. Handicraft industries, includ-
ing silk reeling, spinning and weaving, also rapidly developed. Around 200 BC silk
from China made its way to middle and western Asia and Europe along a route
that became known as the Silk Road (Institute of the History of Natural Sciences,
1985). In the Nong Sang Tong Jue (Handbook for Farming and Mulberry) it is said
that ‘among the nine prefectures, each field is different in its landscape, water con-
dition and climate. Different crop varieties are suitable for different fields.’ It was
recorded in the Xia Zhou Shu that ‘The following is law: To cut the trees on the
mountain in spring is forbidden, fishing is forbidden in water areas during sum-
mer.’ This was the first law for the protection of natural resources. In the Huainan
Tz i, it was also pointed out that ‘Those pregnant cannot be killed; those in egg
stage cannot be fetched; fish shorter than 12 inches cannot be caught; pigs younger
than one year should not be eaten.’