Document Type : Research Paper

Authors

• Faezeh Khani ¹
• Ali Assadi-Alamouti ²
• Behzad Khorrami ³

¹ Department of Animal and Poultry Sciences, Faculty of Agricultural Technology (Aburaihan), University of Tehran, Tehran, Iran. E-mail: Khani.faezeh@ut.ac.ir

² Corresponding Author, Department of Animal and Poultry Sciences, Faculty of Agricultural Technology (Aburaihan), University of Tehran, Tehran, Iran. E-mail: a.alamouti@ut.ac.ir

³ Department of Animal and Poultry Sciences, Faculty of Agricultural Technology (Aburaihan), University of Tehran, Tehran, Iran. E-mail: bkhorrami@ut.ac.ir

Abstract

Objective: Due to increasingly adverse climatic conditions, livestock producers in Iran are experiencing challenges with forage supply. Barley (Hordeum vulgare) is a suitable cereal crop for intercropping with forage pea (Pisum arvense L.), as it can supply a significant portion of the protein demand for growing livestock and dairy cows with a reasonable protein yield per hectare. Given the benefits of legume-cereal forage intercropping and the national trend toward winter cropping for forage production, the legume-cereal ratio in forage crop mixtures is critical to achieving maximum agronomic performance, water use efficiency, nutritional value, and livestock utilization. Thus, the objective of this study was to evaluate the impact of various proportions of whole-crop barley to forage pea on silage fermentation quality and digestibility. 
Methods: Whole crop barley and forage pea were harvested at specific growth stages (early dough stage for barley and mid-flowering to late flowering/early pod formation for forage pea). The experiment comprised four treatments: 1- 100% barley silage, 2- 80% barley+ 20% forage pea silage, 3- 70% barley+ 30% forage pea silage, and 4- 60% barley+ 40% forage pea silage, each with three replicates in a completely randomized design. 
Result: Increasing the proportion of forage pea led to a reduction in dry matter and an increase in pH, and significantly increased crude protein and crude ash contents, while not affecting the values of crude fat, acid detergent fiber, neutral detergent fiber, lignin, and acid detergent insoluble nitrogen. Also, increasing the proportion of forage pea significantly elevated the percentage of ammonia nitrogen in the silage. The acetic, propionic, and butyric acid concentrations of all silages were not significantly different and were within the range of well-fermented silages. A mixed silage of 20% forage pea had a higher gas production volume, organic matter digestibility, metabolizable energy, and short-chain fatty acids compared with forage barley ensiled as the sole crop (P<0.05). 
Conclusions: The results showed that the addition of forage pea to barley silage increased crude protein and reduced fiber, while maintaining the dry matter and water-soluble carbohydrates advantage of barley forage. This method may be an economically viable method in hot climates to enhance feed quality, reduce costs, and be environmentally sustainable. The results of the present study indicated that a 20% inclusion level of forage pea mixed with barley forage is recommended; however, the optimal intercropping ratio of barley-pea forage will be confirmed by further research on the animal performance in conjunction with the results of the agronomic performance of the mixed-crop silages.

Keywords

• In vitro gas production
• Mixed silage
• Pea (Pisum arvense L.)
• Winter-sown forage