Weed Management and Tobacco Production Are Influenced by Cropping Systems Including Cover Crops and Reduced Tillage

Tobacco (Nicotiana tabacum L.) is an industrial crop cultivated worldwide with intensive management systems that include continuous cropping, conventional tillage and high use of agrochemicals. The increasing concerns about environmental and economic sustainability call for innovative practices to maintain yield while managing weeds and enhancing soil fertility. Our research investigated the effect of green manure or cover crops coupled with minimum tillage on Kentucky tobacco production and the level of control of weeds. Six integrated management systems were tested in a four-year trial in Tuscany, Italy: (TS1) conventional farming management as defined above; (TS2) reduction in fertilizers and compost application; (TS3) rotation of tobacco–leguminous green manure and reduction in fertilizers; (TS4) rotation of tobacco–leguminous green manure and compost application without fertilizers; (TS5) rotation of tobacco–mixture of cover crops, minimum tillage before tobacco transplant, reduction in fertilizers; (TS6) as in TS5 but with a compost amendment addition. The different farming practices represented an ecological filter for the weed communities. The combination of conventional tillage, compost application and green manure was sufficient to control weed development. On the other hand, cover crop termination via roller crimper and minimum tillage did not reduce weed pressure, thereby negatively affecting tobacco production. Further studies are needed to improve the effectiveness of mulching and minimal tillage on weed levels not detrimental to tobacco development. It would be advisable to alternate different weed management strategies to prevent community specialization, mitigate negative effects on crops and enhance biodiversity at the farm scale.