No-tillage drilling of Italian ryegrass (Lolium multiflorum L.): Crop residue effects, yields and economic benefits

Variable practical results have been observed for no-till (NT) drilling of grasslands in Galicia, northwest Spain. One of the possible explanations to this erratic behaviour could be the influence of different types of stubble on drill performance and grassland emergence. Because the rotation of silage corn (Zea mays L.) with grassland is the most popular rotation in the Galician dairy farms at present, NT drilling of Italian ryegrass on corn stubble and ryegrass stubble was evaluated. Results were compared with NT drilling after shredded stubble and with conventional drilling (with tillage) for 5 years. Annual ryegrass establishment, biomass production, and forage production were measured each year. Treatments considered were: (1) NT on shredded ryegrass stubble; (2) NT on ryegrass stubble; (3) NT on corn stubble; (4) NT on shredded corn stubble; (5) conventional tillage (CT). Better plant stands and more forage production were obtained on the CT and NT-shredded treatments. Allelopathic effects were not observed, and the differences in plant stands among treatments could be caused by the physical effects of stubble and not by its physiological effects. The shredding operation improved plant stands and forage production of Italian ryegrass, which were not influenced by the type of stubble. Years with abundant rainfall negatively affected crop development, which was more evident in NT treatments. NT methods had advantages in terms of timeliness and low economic costs, as compared to CT.