Regular laboratory analyses of soil and plant samples from various parts of the field can help-but such expertise is costly, and often unavailable.

如若能在实验室里对土壤和不同地块的庄稼样本进行一个常规分析的话，就能避免这种情况。但这种专业手段不仅花费颇高，而且也不是哪儿都能提供的。

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Much ancillary data are needed for computing the attenuating effects of the vegetation layer in the soil moisture retrieval model before, and the ancillary data are often unavailable.

原有的反演算法中，在计算这部分影响的时候，需要大量的关于地表植被状况的辅助数据，而这些即时的辅助数据往往不易获得。

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