Quantitative and Qualitative Characteristics of Forage in the Sorghum (Sorghum bicolor L. Moench) and Berseem Clover (Trifolium alexandrinum L.) Intercropping Systems

This study was conducted to evaluate the forage yield and quality in the additive and replacement series of sorghum and Berseem clover intercropping.

The experiment was conducted in a randomized complete block design with three replications in the Research Farm of Seed and Plant Improvement Institute, Karaj, Iran, during two cropping seasons (2016 and 2017). Cropping systems included replacement series (S75C25: 75% Sorghum + 25% Clover; S50C50: 50%+50%; and S25C75: 25%+75%), additive series (S100C50: 100%+50%; S50C100: 50%+100%; and S100C100: 100%+100%), and sorghum and clover monoculture (S100C0 andS0C100, respectively).

The highest and lowest forage yields were obtained from S100C100 and S0C100 cropping systems, respectively. In addition, the highest content of digestible protein (11.48%), metabolizable protein (8.03%), digestible energy (2.77 Mcal.kg-1 DM) and relative forage quality (122.74%) was obtained in the S0C100. Also, the maximum yield of digestible and metabolizable protein (1956 and 1369 kg.ha-1, respectively) and the highest energy production for lactation (3.92 Mcal.m-2) were obtained in the S100C100. Among the additive series, only the S50C100 intercropping system was able to produce acceptable forage quality.

Considering the quantity and quality of produced forage, the S50C100 intercropping system (with 24.28 t ha-1 dry forage yield and relative forage quality equivalent to 91.04%) is introduced as the superior treatment. In general, additive intercropping systems of sorghum and berseem clover increased the quantitative and qualitative yield of forage and could be a good alternative to monoculture systems of these crops.