Improving soil health and system productivity through conservation agriculture and weed management strategies in rice-maize cropping system

Subhra Sahoo^1,2Dhirendra Kumar Roy^1*Shivani Ranjan^1*Souvik Sadhu³Sumit Sow^1*Dibyajyoti Nath⁴Majed Alotaibi⁵Nawab Ali⁶Mahmoud F. Seleiman⁷

• ¹Department of Agronomy, Dr. Rajendra Prasad Central Agricultural University, Samastipur, India
• ²Teagasc Oak Park Crops Research Centre, Oak Park, Ireland
• ³Department of Soil Science and Agricultural Chemistry, Bihar Agricultural University, Sabour, India
• ⁴Department of Soil Science, Dr Rajendra Prasad Central Agricultural University, Samastipur, India
• ⁵Department of Plant Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
• ⁶Department of Biosystems and Agricultural Engineering (BAE), College of Agriculture and Natural Resources,, Michigan State University, East Lansing, United States
• ⁷Department of Plant Production, College of Food and Agriculture Sciences,, King Saud University, Riyadh, Saudi Arabia

Conservation agriculture (CA)-based rice-maize cropping system (RMCS) can be the possible option for higher productivity and maintain soil health in the Indo Gangetic Plains. However, weed infestation remains the major constraint in its adoption. Hence, to adopt CA practices and at the same time manage weed population, a field experiment was carried out at Dr. Rajendra Prasad Central Agricultural University during 2019-20 and 2020-21. Treatments consisted of four main plots of different tillage practices, viz. zero- till direct seeded rice followed by zero-till maize (ZTDSR fb ZTM), direct seeded rice followed by maize on permanent raised beds with residue (PBDSR+R fb PBDSM+R), PBDSR followed by PBDSM without residue (PBDSR-R fb PBDSM-R) and conventional tilled puddled transplanted rice followed by conventional tilled maize (CTR fb CTM). On the other hand, sub-plots comprised of five weed management options, viz. unweeded control, vermicompost mulch, P-enriched vermicompost mulch, live mulch and weed-free. The two-year study revealed that the combination of PBDSR+R fb PBDSM+R emerged as the most effective tillage practice, showing a maximum reduction in bulk density (0.07 Mg m⁻³) and improvements in water holding capacity by 8.1%, soil organic carbon by 8.2%, soil microbial biomass carbon by 32.7%. Among weed management practices, P-enriched vermicompost mulch resulted 18.8% higher dehydrogenase activity of soil with greater nutrient availability as compared to live mulch. In contrast, CTR fb CTM significantly deteriorated soil health. The maximum maize REY (9.3 t ha-1) and system productivity (15.9 t ha-1) were also recorded under PBDSR+R fb PBDSM+R, with increases of up to 15.2% and 25.2% over conventional practices in the second year. Overall, CA practice mainly permanent bed with residue coupled with P-enriched vermicompost mulches demonstrated strong potential for improving soil health and sustainable crop productivity in RMCS.