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A sample of 36 tenant farmers, at varying locations along the Hamza Minor Canal of the Sudan Gezira Scheme, were surveyed in 1986/7, the purpose being to estimate locational variation in irrigation water supplies and. tenancy income levels. Results show that for the main crop, cotton, there are declines in water balance, crop yields and net returns between head, middle and tail end of the canal. However, in middle and tail‐end locations groundnuts yield a substantially higher net return per hectare than the main crops, cotton and wheat, which suggests that changes in crop rotations would be profitable.  相似文献   
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Microsystem Technologies - In this paper a novel spiral inductor with high quality (Q)-factor is presented. Non-uniform current density distribution, especially in inner turn, increases the...  相似文献   
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