各个年龄段阴茎的长度:帮忙翻译一小段英文

There is a lack of any systematic analysis of the actual costs and potential benefits so that it is difficult to make comparisons between alternative land degradation control technologies, approaches and investment projects. Those engaged in the design and implementations of land degradation control projects tend to promote a limited range of technologies for which use centrally determined standard unit costs. Calculations are made as to the benefits that can be expected to accrue from an area of land once the conservation measures have been installed. However there is a poor understanding of how much of any increase in production can be directly attributed to the soil conservation, and how much is due to other farm management improvements (eg. use of improved varieties, fertiliser etc). There is also no direct link between the cost and the benefit to determine whether the investment has been financially and economically worthwhile. This discourages the search for alternative land management practices that might achieve the same conservation and production benefits at a lower cost, which in turn would improve the economic and financial rate of return from project investments.
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