ABSTRACT
The root is an important organ that plays a signi‰cant role in the growth and development of plants. Roots not only supply water and nutrient to plants but also give mechanical support from seedling through maturity and development. In addition, growth hormones are also supplied by roots to the plants, which help in their better growth and development. Furthermore, roots improve the organic matter content of the soil, which is responsible for improving the physical, chemical, and biological properties of the soil, resulting in higher crop yields. Barber (1979) estimated that 8%–11% of corn stalk residues were transformed into soil organic carbon, while at least 18% of corn roots were transformed into soil organic carbon. Allmaras et al. (2004) showed that the measurement of the quantity of plant roots alone underestimates the role of roots in the formation of soil organic carbon. They noted that rhizodeposition in the ‰eld is a large contributor to the total carbon (C) cycle and must be included in the analysis at the ‰eld level. Johnson et al. (2006) summarized the contributions of different plant parts from different plant species to soil organic carbon and gave guidelines for including the contributions of plant roots and rhizodeposition to the total C cycle when analyzing changes in soil organic carbon. Belowground deposition of ‰xed C in structural root biomass, exudates, mucilage, and sloughed cells may be a major source for soil organic carbon accumulation (Bottner et al., 1999; Allmaras et al., 2004). Benjamin et al. (2010) reported that the contribution of the crop root system to the formation and increase of soil organic carbon is important when considering the selection of a crop rotation in a cropping system.
