Using Sorghum to suppress weeds in dry seeded aerobic and puddled transplanted rice

Weed infestation is one of the major problems in dry seeded aerobic rice (DSAR). Modern agriculture primarily relies on the use of synthetic herbicides for weed control in field crops. Nevertheless, overuse of these herbicides can lead to numerous health and environmental issues and the evolution of herbicide-resistant weed biotypes. The phenomenon of allelopathy may be valuable for overcoming this problem. In this study, we evaluated the potential of Sorghum allelopathy for managing weeds in rice grown in rotation with wheat, under two rice production systems (puddled transplanted (PudTR) and DSAR). Sorghum was planted in the last week of April and harvested during the second week of June. After the Sorghum harvest, rice was raised either as PudTR or DSAR. In addition, other allelopathic strategies were included as treatments: (a) Sorghum water extract (SWE) (18 L ha⁻¹), (b) Sorghum mulch (SM) (8 t ha⁻¹) and (c) SWE (18 L ha⁻¹) + SM (8 t ha⁻¹). The combined use of SWE and SM in DSAR grown after Sorghum reduced the weed population and total weed dry weight by 77% and 78%, respectively, when compared with the fallow–DSAR treatment. Similarly, the SWE + SM treatment in PudTR grown after Sorghum reduced the weed population and total weed dry weight by 74% and 84%, respectively, compared with the fallow–PudTR treatment. The Sorghum–DSAR plus SWE + SM produced the highest grain yield (4 Mg ha⁻¹) while the fallow–DSAR with no SWE or SM produced the lowest grain yield (2.15 Mg ha⁻¹). The improved weed management and grain yield by combining allelopathic approaches enhanced the profitability of both DSAR and PudTR. In crux, the application of SWE + SM has remarkable potential for reducing weed infestations and improving the yield and profitability in DSAR and PudTR.