The effect of conservation and conventional tillage systems on forage quality evaluation indices and nutrient concentrations in forage legumes

Abstract An experiment was carried out at the Lorestan Agricultural and Natural Resources Research and Education Center from 2021 to 2023 to evaluate the effects of conservation and conventional tillage practices on the quality of forage and nutrient concentrations in legumes. This study utilized a split plot design within a randomized complete block framework, comprising three replications. The primary factor examined was the tillage method (conventional, low-tillage, and no-tillage), while the secondary factors included various forage legumes (Broujerd landrace faba bean, Lamei cultivar vetch, Grass pea, Barakat, and Feyz cultivar faba bean). The traits assessed encompassed forage quality indicators (such as dry matter digestibility, crude protein, water-soluble carbohydrates, crude fiber, ash, acid detergent fiber, and neutral detergent fibers) as well as shoot nutrient concentrations (including nitrogen, phosphorus, potassium, iron, zinc, copper, and manganese). The research aimed to compare the impacts of different tillage systems and forage legume varieties on nutrient composition. The conventional tillage system utilizing the Lamei variety of vetch exhibited the highest copper concentration at 50.17 ppm. Similarly, the highest phosphorus levels, recorded in 0.85% and 0.84%, were also observed in both the conventional and low-tillage systems with Lamei vetch. In terms of zinc concentration, the low-tillage system with Lamei vetch reached a peak of 50.69 ppm. Furthermore, the no-tillage system featuring the Barakat cultivar of faba bean demonstrated the highest acid detergent fiber content at 35.12%. The findings indicate that the conventional tillage system significantly enhanced various nutritional parameters compared to the no-till system, including a 12% improvement in dry matter digestibility and a 27% increase in potassium levels. Overall, the study concluded that employing conventional and low-tillage systems, along with the cultivation of the Lamei variety of vetch, resulted in superior forage quality traits and nutrient content in shoots compared to the no-tillage approach.