By Anthony E. Hall
The semi-arid zones of the area are fragile ecosystems that are being sub stantially transformed through the actions of mankind. expanding human populations have led to larger calls for on semi-arid zones for offering human susten ance and the prospect that this can improve desertification is a grave main issue. those zones are harsh habitats for people. The famines that resulted from drought throughout the past due 1960's and the 1970's within the African Sahel illustrated the unreliability of current agricultural structures during this sector. huge fluctuations in ag ricultural creation have happened in semi-arid zones of Australia, North Ameri ca, and the Soviet Union as a result of periodic droughts, although significant ag ricultural know-how has been dedicated to agricultural improvement in those zones. The problem to mankind is to control those diverse semi-arid zones in order that professional ductivity is elevated and stabilized, and environmental deterioration is reduced. Irrigation can be utilized to extend and stabilize agricultural creation in semi-arid zones as mentioned in quantity five of this sequence, Arid sector Irrigation. the current quantity, Agriculture in Semi-Arid Environments, specializes in dryland farming in semi-arid zones, and is appropriate to the big parts of the realm the place rainfall is restricting and the place water isn't really on hand for irrigation. This quantity is designed to help agricultural improvement in those parts and contains reports and analyses of accessible info via scientists operating in Africa, Australia, and on the U ni versity of California.
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Extra info for Agriculture in Semi-Arid Environments
Tolstov (1948a, 1948b, 1958). In late Neolithic times, primitive hoe-farming began on the flooded delta lands of the Amu Darya River (Kovda, 1961). In this area, an extensive network of naturally formed river channels and shallow streams (characteristic of deltas) contributed to the development of an irrigation system. At first ditches were dug to convey rising water during flood periods from the natural channels of the delta onto lands used for crop-growing. In later stages of delta settlement, these natural river channels were transformed into large artificial canals.
Ordinarily wild plant foods [especially mesquite (Prosopis juliflora)], fish, and game animals constituted 50% to 70% of the diet. In years of crop failure, the Indians relied solely on hunting and gathering. On the Lower Gila agriculture was of less importance than on the Lower Colorado. The major floods on the Gila occurred in January and February, and planting was done immediately after the floodwaters subsided (Spier, 1933). A second crop was also sown in mid-summer. Although the data are not complete, it would appear that summer thunderstorms were important in providing water for this crop.
J. Wilke leading part of the system, about 25 ha were affected by irrigation, although the system was capable of watering up to 80 ha. The population of the settlement of Geoksyur was estimated at 700-1500 (Lisitsina, 1969). It was calculated one of the canals could have been built readily by 100 men working a total of 25 days. According to Lisitsina (1969), it has not yet been possible to determine if this ancient Turkmenian irrigation system was oflocal origin or derived from an idea of irrigation brought in by newcomers from regions farther south, such as Iran or Mesopotamia.