Weed seedbank, above‐ground weed community and crop yields under conventional and conservation agriculture practices in maize–wheat–mungbean rotation

Abstract

AbstractWeeds are the major biological barriers to achieving higher yields in agro‐ecosystem. We aimed to determine weed community (seedbank and aboveground) and crop yield responses to conventional tillage (CT) and different types of conservation agriculture (CA) practices with variable nitrogen (N) doses in a maize (Zea mays L.)–wheat (Triticum aestivum L.)–mungbean (Vigna radiata L.) rotation. After 8 years of implementation, CA practices including zero‐tilled (ZT) permanent narrow‐bed with crop residues and 100% required N (PNB + R + 100 N), and ZT permanent broad‐bed with residues and 100% required N (PBB + R + 100 N) had a lower weed seed density by 45% at 0–7.5 cm and 53% at 7.5–15 cm soil layers than CT. CT promoted dominance of Cyperus rotundus L., Cyperus esculentus L. and Dinebra retroflexa (Vahl) Panz. while, specific CA practices (PNB + R + 100 N and PBB + R + 100 N) promoted dominance of Digera arvensis Forsk. and Melilotus indicus (L.). Compared to PNB + R + 100 N and PBB + R + 100 N, CT seedbanks had 41–46% higher ecological dominance, which is an indicator that delineates dominance of few specific weed species. The PBB + R + 100 N also had a lower total above‐ground weed density in maize–wheat–mungbean rotation by 34% (mean of years) than CT. The PBB + R + 100 N had 31.1% higher system productivity over CT. Thus, PBB + R + 100 N could reduce the weed seed density in the soil and above‐ground weeds and increase crop yields for sustainable crop production in maize–wheat–mungbean rotations.