Plants Competitions Influence Carbon Partitioning Below and Above Ground Parts among Warm Season Cereals (Maize, Sorghum & Millets)

Abstract

Abstract Increasing the efficiency of carbon (C) sequestration through cropping system e.g., intercropping and mixed cropping play an important role to increase total C accumulation and it’s partitioning into shoots above the ground and roots below the ground. Unfortunately, there is lack of research on carbon content (CC) accumulation and its partitioning into roots and shoots when the plants competes each other in mixed cropping. Therefore, a hypothesis on the CC accumulation and partitioning into shoots and roots of summer cereals crops as mixed cropping under two different water levels (low and high) was tested. The hypothesis was supported by the results, and considerable variation was observed in ACC, BCC and TCC under different stands and water levels. The corn plants in pure stand (T1) had higher ACC (7.82 g C plant− 1), BCC (1.43 g C plant− 1) and TCC (9.24 g C plant− 1) than the pure stands of sorghum (T2) and millets (T3). The ACC, BCC and TCC of the three crops mixed stand was lower than two crops mixed stand. Corn mixed either with sorghum (T4) or millets (T5) had higher ACC, BCC and TCC than sorghum and millets, and sorghum mixed with millets had higher ACC, BCC and TCC than millets plants. Among the three crops, the higher ACC, BCC and TCC of corn (T7) was attributed to its higher CGR, higher WUE, higher competition ratio, higher DM accumulation and greater partitioning into shoots and roots. Grain sorghum ranked second and foxtail millets ranked third in terms of ACC, BCC and TCC in the mixed (corn > sorghum > millets). Corn was found the best competitor to sequester more CO2 from atmosphere when grown mixed either with sorghum or millets, while millets was declared the least competitor that sequester the less atmospheric CO2 when grown mixed with corn or sorghum (corn > sorghum > millets i.e. 9.24, 2.17 and 1.31 g C plant− 1, respectively).