Real maize roots in the soil and issues should be considered by study

How do real roots grow and work in the soil? Because soil is opaque growing environment, it is not possible to observe or study roots grown in the soil directly. Therefore, less is known about the real root growth and development, its spatial distribution as well as its nutrient uptake in the soil. In this paper, the following issues were discussed with maize as an example: the growth and development, and renewal and senescence of real roots in the soil during the whole growth period; the relationship between root length and dry weight; the formation of rhizosheath; root growth and nitrogen use efficiency; soil Nmin, and especially the attention should be paid during the study of real roots in the soil. The aim of this paper is to let a better understanding of the growth and development of real maize roots in the soil though the discussion mentioned above, and to use for reference for the investigation of crop roots grown in the soil.