LAND DEVELOPMENT 313
return for which they could borrow food, seeds, and, in lean years,
rice.
Wet paddy lands were very important to the agricultural operations
of powerful peasants who were prosperous enough to use oxen for
spring plowing. For weak, poor peasants, however, the wet paddy
lands were of little consequence, and dry fields or yakihata were the
most common form of cultivable land.
16
Wet paddy lands were devel-
oped using a compost of grass trampled by oxen and horses and cut
grass containing saplings and young leaves. During the second half of
the medieval period, they also discovered that the crop yield improved
when ashes from burnt trees were used. The average yield of one tan of
paddy land cannot be accurately estimated, but uplands generally
yielded about one koku, two or three to of
rice.
Dry fields were usually
planted with barley, and yakihata were usually planted with millet and
buckwheat. Paddy land with much richer soil and higher productivity
was planted with rice.
Various technological advances improved the agricultural output
starting in about the second half of the thirteenth century. New and
improved varieties of wetland rice were developed, and depending on
the climate, even triple cropping was possible. Run-off ditches were
built in both valley lands and moist lowlands. After the wetland rice
was harvested, the water was drained off, and barley was planted as a
second crop. Needless to say, the productivity of wet paddy lands
increased with such concentrated usage.
17
A variety of crops were planted in dry fields: grains such as barley
and soybeans, vegetables, hemp, mulberry for sericulture, and the
perilla plant. Until the mass production of cotton began in the six-
teenth century, hemp was the most widely used fabric for clothing.
18
Sericulture, including removing the silk from cocoons and making silk
floss and silk goods, was another endeavor of the peasants, although
strictly a luxury line. Silk floss was referred to as gofukumen (dry goods
cloth) and was taxed as nengu in many areas. The raising of cocoons
was difficult because in some years disease killed all the silkworms.'
9
16 On yakihata, see Kuroda Hideo, "Chusei no kaihatsu to shizen," in Seikatsu, bunka, shiso,
vol. 4 of Ikki (Tokyo: Tokyo daigaku shuppankai, 1981), pp. 91-130.
17 Double cropping was already being practiced in some areas by the end of the Heian period,
but in the late Kamakura period the problem arose concerning whether nengu should be
exacted in the form of barley, the second crop on wet paddy lands.
18 Echigo Province was noted for its hemp thread in the Muromachi period, and hemp cloth was
one of its major products. The production of hemp, however, was not limited to Echigo but
took place throughout Japan.
19 The ritsuryo government required that mulberry, along with lacquer trees, be cultivated in
orchards and taxed the silk thread taken from the cocoons. In the medieval period, however,
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