- Agronomic: grass (misc. annual), sorghum sudangrass
- Animals: bovine
- Animal Production: grazing management, grazing - rotational
- Crop Production: intercropping
Warm season annuals such as corn (Zea mays L.) and brown mid rib (BMR) sudangrass [Sorghum bicolor (L.) Moench.], can increase the carrying capacity of grazing farms by producing great amounts of forages during mid-summer, when cool season pasture growth rates decline. These warm season annuals can be interseeded into a perennial forage, such as Kura clover, to reduce soil erosion and provide forage of greater digestibility and protein to grazing cattle. In addition, cereal rye can be added to the system to provide weed control and additional grazing forage in early spring.
The study was conducted from 2014 to 2016 at the Arlington Agricultural Research Station in Arlington, WI. Pre-grazing biomass did not differ between species. Corn averaged 3033 ± 174 lb ac-1 (mean, SEM), while sudangrass averaged 2926 ± 143 lb ac-1, but treatments differed by year (P < 0.05). Harvested forage yield was greater (P< 0.05) in sudangrass-Kura clover, averaging 3071 ± 199 lb ac-1, while corn-Kura clover averaged 2164 ± 172 lb ac-1. Average daily gain was not different (P > 0.05) between corn-Kura clover (1.3 ± 0.24 lb d-1) and sudangrass-Kura clover (1.7 ± 0.12 lb d-1). Average daily gain was affected by year and year by species (P < 0.05). Corn-Kura clover had a lower (P = 0.05) gain per acre, 174 ± 41 lbs per acre, than sudangrass-Kura clover, 284 ± 41 lbs per acre, and there was also a year effect (P < 0.05) and a tendency for a year by species effect (P = .09). Though no differences in ADG were detected, greater gain per acre was achieved due to more grazing days for sudangrass-Kura clover. Economic comparison on a per acre basis was favorable for the sudangrass-Kura clover system, because of increased gain per acre compared to corn-Kura clover. However, when compared to adjacently grazed perennial cool season pastures (binary mixtures of alfalfa and grasses, gain per acre averaged 810 lbs per acre), costs were much greater for both annual systems without increased gain per acre. The input/output difference for the average cool season perennial system over the 4 years (establishment plus research years) was $2075 per acre, while sudangrass-Kura clover was $102 per acre and corn-Kura clover was $-477 per acre, concluding that cool season perennial systems are more profitable in this comparison. However, similar ADG between the cool season perennial system and the proposed warm season system is promising, but adjustments are necessary for the warm season system to increase gain per acre.
The objectives of this study were to quantify annual forage production, forage nutritive quality, and animal gain on sudangrass and corn interseeded into Kura clover. To compare the two systems forage production, forage nutritive quality, animal gain, and number of grazing days were measured. Additionally, an economic analysis will be completed to determine the costs of planting and maintaining both systems, plus a comparison to a typical cool season perennial system.