Corn yield response to tillage with furrow irrigation

Conservation tillage techniques have gained widespread, but not universal, use in irrigated corn (Zea mays L.) production. This study was conducted to evaluate yield impacts associated with conservation tillage methods when c ompared with conventional techniques in a replicated field experiment for 1 7 consecutive years in Nebraska (1976-1992). Six tillage treatments were im posed on continuous corn production and replicated three times. Tillage tre atments ranged from traditional (disk and surface plant) to no-till (slot p lant on existing ridge). Post-plant operations were uniformly applied to ac commodate furrow irrigation. Over the life of the project the conservation tillage treatments (ridge tilt, rotary till, and slot plant) had a 4 bu/acr e increase in grain yield over the conventional treatments (those having ch isel, disk, or lister operations). The advantage of the conservation tillag e systems was amplified by corresponding lower production costs. The rotary , ridge, and slot tillage systems had $7.72, $14.22, and $16.22/acre lower annual tillage and herbicide costs (1990 dollars), respectively, than the c onventional tillage system with a disking operation. The conservation tilla ge treatments significantly lowered stalk rot and residual spring soil nitr ate N concentrations. Other comparisons showing significant differences wer e list vs. chisel and disk for harvest population and soil potassium concen trations, and ridge vs, rotary for harvest population. None of the other co mparisons tested had significant differences for grain yield or other soil parameters. Overall, this study indicates that conservation tillage on irri gated continuous-corn is advantageous over conventional methods.