European Journal of Sustainable Agroecosystems

Background: There are persistent challenges in the application of effective cropping systems such as weed disturbance, declining soil organic matter, and loss of agrobiodiversity. Cover crops have been widely disseminated as conservation practices although there is limited knowledge on the possible different effects of various cover crops differently on the efficiency of these practices. Therefore, the objective of this experiment has been to compare the four different cover crop mixtures, namely cover crop with legumes, cover crop with grasses, cover crop with brassicas, and cover crop with legumes, against cover crop with legumes in order to understand the extent of their impact on the effectiveness of different cropping systems in a two-year field experiment.
The study was conducted in randomized replicated block design at the temperate climate research site where farm land is plain and consists of loam soil with sedentary cereal crop production. The following treatments were used: cover crop of legume mixture, cover crop of grass mixture, cover crop of brassica mixture, and cover crop with legumes. The analysis included cover crop biomass, weed density and biomass, soil organic carbon, bulk density, aggregate stability, nutrient availability, microbial biomass and enzyme activity.
Results: The use of multi-species mixtures generated the highest biomass above the ground and highest degree of weed suppression efficiency. Grass and brassica mixtures came in succession after the multi-species mixture in terms of above-ground biomass production and weed suppression efficiency. Soil organic carbon, aggregate stability and microbial biomass carbon have increased the most in the case of application of multi-species and legume treatments when compared to a fallow control. In addition, the crop yield recorded after the use of multi-species and legume mixtures was higher in comparison to the control, which brought about the positive on-farm partial economic returns, despite establishment costs. Moreover, the correlation analysis demonstrated that weed suppression efficiency, ground cover and soil biological indicators are closely associated with one another. 
Significance: Diversified cover crop mixtures provide both agronomical and ecological advantages.
Conclusion: Multi-species cover crop mixtures serve as an efficient evidence-based approach to weed management and soil restoration in conservation agriculture systems.