Comparison of yield, nutritive value, and in vitro digestibility of monocrop and intercropped corn-soybean silages cut at two maturity stages

Limited information on nutrient composition and in vitro digestibility of corn-soybean intercropped silage is available. The objective of this study was to compare corn (Zea mays L.) or soybean (Glycine max L. Yesilsoy) monocrop silage with corn-soybean intercropped silages in term of yield, nutritive value, and in vitro digestibility. Intercropping was as follows: 1 row corn to 1 row soybean (1M1S), 1 row corn to 2 rows soybean (1M2S) and 2 rows corn to 1 row soybean (2M1S). The crops were harvested when the corn reached 3/5 or 1/4 milk line. The silage samples were analysed for pH, dry matter (DM), crude protein (CP), ether extract (EE), neutral (NDF) and acid detergent fibre (ADF), calcium, potassium, magnesium and phosphorus. Also, in vitro true (IVTD) and in vitro NDF (IVNFD) digestibilities were determined in the silages samples. The DM, EE, calculated non structural carbohydrate values were higher in silage harvested at 1/4 than 3/5 milk line. All intercropped silages had higher CP values (1M1S, 8.3%; 1M2S, 10.1%; 2M1S, 8.0%) than the monocrop corn (SM, 6.8%) silage. The NDF and ADF levels were higher for 1M1S, 2M1S and SM compared with 1M2S and monocrop soybean (SS) silage. In vitro true DM digestibility of all silages increased with maturity stage; it was higher for the 1M2S than other silages. It is concluded that corn-soybean intercropped silage has better nutrient composition and digestibility than SM or SS silage.