Another theoretical problem raised by the grain price data, also illustrated in Li's article, is that of how to define and identify markets.
李明珠的文章也显示了另一个由谷物价格引发的理论问题，即如何定义和界定市场。
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A third approach — growing paddy rice aerobically in raised beds — reduces the mobilization of soil arsenite and "can dramatically decrease arsenic transfer from soil to grain," McGrath says.
Minimum purchase prices and temporary purchase and storage policies were put in place for key grain varieties, and the minimum purchase prices for wheat and rice were raised by between 25% and 40%.