A significant acreage of agricultural land in the Northeast USA cannot produce economic yields of corn silage. This has resulted in a growing interest in the use of brown midrib (BMR) sorghum sudangrass as a forage crop. Research conducted in New York over 5 years has shown tremendous advantages of growing BMR sorghum sudangrass: it produces yields equal to or higher than silage corn in both wet and dry seasons. The crop is adapted to a wide range of soil types, topography, low soil pH, high temperature and excess moisture. Milk production from BMR sorghum sudangrass crop can equal or even exceed that from silage corn. With multiple cut systems and high N application rates, BMR sorghum sudangrass can produce twice as much protein as corn silage. The BMR sorghum sudangrass has high digestibility and has the potential to support a high forage diet. A high forage diet reduces the amount of feed concentrates brought onto the farm and this in turn reduces P loading on farms from imported animal feed.
The BMR sorghum sudangrass may have less detrimental effect on the environment compared with corn silage. The USDA NRCS rates the soil erosion potential of sorghum sudangrass as half that of corn. The crop has rapid emergence and this may negate the need for herbicides. Also, there is no need to use insecticides and nematicides as both insects and nematodes do not cause economic losses. Likewise, crop damage from rodents or deer is minimal. A 2- or 3-cut system is possible with BMR sorghum sudangrass. This allows for a split application of manure in summer when the risk of nitrogen losses through leaching, denitrification and phosphorus losses through runoff is reduced.
The BMR sorghum sudangrass is more tolerant of a shorter growing season than silage corn, allowing for more flexibility in planting date. Likewise, it has a larger harvest window than silage corn, allowing for better utilization of labor and farm equipment.
The transition from growing silage corn to BMR sorghum sudangrass is not expected to be expensive for farmers. The crop can be grown using the conventional hay forage planting and harvesting equipment. This eliminates the need to invest in extra machinery.
The agronomic management of BMR sorghum sudangrass is not well defined because BMR sorghum sudangrass is a relatively new crop to the Northeast USA. Optimal fertilizer recommendations are not currently known. Analysis of forage characteristics, including crude protein (CP), neutral detergents fiber (NDF), digestibility, relative milk yield per ton and milk yield per acre need to be evaluated. This information is required for assessing the suitability of BMR sorghum sudangrass as a forage for high producing dairy cattle (NRC, 2001).