Comparison of forage production potential in Berseem clover– Proso millet intercropping with sole cropping in cold regions

Introduction: The use of plants with the ability of second or summer cultivation in cold regions such as Shahrekord can increase production per unit area and the optimal use of productive resources such as land. Unlike sole cropping system, intercropping in line with ecological goals (Salama, 2020) brings increased resource consumption efficiency and yield stability (Bitew et al., 2021). Therefore, this study was designed and implemented: (i) to investigate the forage yield of Proso millet and Berseem clover in sole cropping and intercropping systems; (ii) to examine the effect of competition between the used species (legume and grass) in the intercropping; (iii) to analyze the interrelationships between the components of the intercropping using different competition indices; and (iv) to evaluate which intercropping managements is better for resource management with respect to forage yield and competition indices.
Materials and Methods: A field experiment based on randomized complete block design was conducted with three replications and five treatments in June 2019 in Shahrekord, Iran. The treatments included intercropping of Berseem clover- Proso millet (75%- 25%, 50%- 50%, 25%- 75%) and sole cropping of each component crops. Harvesting of all treatments was done in the milking stage of seed millet (late September). The evaluated traits were wet forage yield (ton/ha), dry forage yield (ton/ha), forage crude protein (%) and forage protein yield (ton/ha). Some competition indices such as land equality ratio (LER) and relative crowding coefficient (RCC) were used to evaluate intercropping systems (Midya et al., 2005). All data were subjected to analysis of variance using the GLM procedure of the SAS statistical program. Also, significant differences among the means were measured using the LSD test (P<0.05).
Results & Discussion: Results showed that intercropping patterns had significant effect on all of the studied traits of Proso millet and Berseem clover. The maximum wet forage yield (16.0 ton/ha) and dry forage yield (5.0 ton/ha) were obtained at 25% Proso millet- 75% Berseem clover and 50% Proso millet- 50% Berseem clover, respectively. The highest percentage of forage crude protein and forage protein yield were found in the sole cropping of Berseem clover, and with the decrease in the share of Berseem clover in intercropping, a downward trend was observed in crude protein as well as yield of forage protein. The highest LER values (1.25) was obtained from 25% Proso millet- 75% Berseem clover. Proso millet with RCC>1 was identified as the dominant species with a higher relative forage yield value compared to Berseem clover in all intercropping systems.
Conclusion: The present study showed that the mixture of Berseem clover with Proso millet, in each of the planted ratios, has the functional advantage of forage production to exploit the available environmental resources compared to their respective monocultures. However, considering the lower competitive power of Berseem clover compared to Proso millet based on the RCC, Berseem clover needs a higher planting density than Proso millet to benefit more from the advantages of intercropping. In general, based on the results of the present study, the treatment combination of 25% Proso millet-75% Berseem clover, is significant in terms of forage production with the desired quantity and quality. On the other hand, the results obtained from the LER confirmed the superior advantage of this combination due to the better efficiency of land use compared to other treatments. This combination can be economically and environmentally promising in the development of sustainable crop production (forage) as a second or summer crop in Shahrekord region or other cold regions.
Keywords: Grass, Leguminous, Dominant species, Equal ratio of land; Forage production
References
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