Among the main constraints to adopting conservation tillage in the semiarid zones in Mexico's north-central region are: low acceptance among farmers, need of specialized machinery, use of herbicides, and above all, the need to utilize stubble to feed animals. The objective of this study was to assess the effect of different tillage methods in an irrigated corn-oat rotation system on corn grain, stubble, and forage oat yield. Seven tillage methods were evaluated: (1) traditional plow and disk (P+D), (2) disturbing the upper 0-4 in layer (D), (3) without disturbing the upper 0-4 in layer (ND), (4) zero tillage with 0% soil cover (ZT+0%SC), (5) zero tillage with 33% soil cover (ZT+33%SC), (6) zero tillage with 66% soil cover (ZT+66%SC), and (7) zero tillage with 100% soil cover (ZT+100%SC). In each year from 1996 to 2007, corn was sowed on the spring while forage oat was grown during the fall-winter season. Corn grain yield results showed statistical differences among treatments (p?0.05), where ZT+66%SC was the best treatment, surpassing by 90% the corn yield registered with P+D. The statistical analysis for corn stubble yield showed no differences (p?0.05) among treatments. With ZT+66%SC, corn stubble production was increased 3.448 ton/ha compared with that of P+D, indicating that farmers can use 2.0 ton ha -1 to cover at least 33% of the soil surface. Forage oat yields within the seven treatments were not statistically different ( P?0.05), but all ZT treatments were no-till seeded. Our conclusions are that corn and forage oat can be no-till seeded, increasing corn production and keeping stable production of forage oat. These results can be used to provide evidence to farmers of the benefits of adopting conservation tillage.
