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中国农作物产量趋势tools

使用说明:选择需要观察产量趋势的农作物,省和县。注意:本tools目的仅用于教育和提供信息,请用户谨慎使用,本tools不承担任何责任。

农作物

Introduction: County level yield data reveal a trend as time increases so the data should be detrended. The purpose is to account for systematic changes in yield levels over time. Other sources of yield variance, like soil type, improved varieties, and increased soil fertility are assumed to be either constant or captured by this detrending process (Cao, 2004). Following Woodard and Garcia (2007), yields are detrended using a simple linear trend model in the tool.