Document Type : Research Paper

Authors

• Nooshin Assadi-Fakhrnejad 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: nooshinasadi@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: The productivity and nutritional quality of ensiled forages, the quality of silage fermentation and its loss are improved by forage harvesting at an appropriate stage of maturity, while, forage intercropping strategies that take the advantage of the additive characteristics of different plant species also enhance the quality of the forage product. The objective of this study was to evaluate the effect of forage maturity at harvest and intercropping on ensiling characteristics, effluent production, and in vitro (laboratory) digestibility in three small-grain forages (barley, triticale and oat).
Method: Whole plant barley was harvested at early heading and hard dough stage of growth; whole plant triticale was harvested at the tillering and soft dough stage, and the oats forage was harvested at the tillering and stem elongation stages. The intercropping treatments consisted of 53% barley, 33% triticale, and 14% oat, harvested at the above-mentioned stages. The experiment was a 2×4 factorial arrangement in a completely randomized design with eight treatments and three replicates.
Results: Dry matter (DM), organic matter (OM), and crude protein (CP) yields increased with growth stages in triticale, oat, and the mixed crop. The highest DM (32.1%) was found in the mixed crop in the second harvest stage and the lowest (13.5%) was observed in the first harvest stage in oats (P<0.001), whereas the highest CP (19.3 %) was obtained from oats in the first harvest, and the lowest (10.8%) from barley in the second harvest stage (P<0.001). The lowest NDF content (49.5%) was observed in oats and the highest (58.2%) in barley (P<0.001). The interaction effect of forage type and harvest time on DM, CP, and ADF contents was significant; however, the other chemical components (ash, lignin, acid-, and neutral-detergent insoluble nitrogen, crude fat, and water soluble carbohydrates (WSC)) were similar between the two harvest stages. Overall, late harvesting increased lignin and decreased CP, WSC, and NDF. Intercropping of oats with the other crops increased CP and improved in vitro digestibility, and it reduced silage NDF content. The silages of the second harvest crops produced no effluent, had an appropriate pH (close to 4.2) and an ammonia nitrogen level of less than 10% total nitrogen, highlightimg good fermentation in the silages with higher DM content.
Conclusions: Results from this study indicated that the second harvest stage (hard dough in barley, soft dough in triticale, and stem elongation in oats) was the appropriate time for harvesting small grain forages whether ensiled as a sole forage or intercropped as it maximized the yield of OM, CP, energy, and digestible DM per hectare. As the yield performance of triticale was superior to that of barley, it is recommended to include triticale as the main crop in intercropping systems.

Keywords

• Intercropping
• Physiological maturity
• Silage quality
• Winter forage
• Yield