A3O-Lancaster Farming, Saturday, September 12, 1992 Foraging Around fl John E. Baylor Forage Specialist (Retired) Penn State University SILO FILLING TIME - IT’S HERE Silage that nice smelling, succulent forage preserved by a controlled anaerobic (in the ab sence of air) fermentation of green forages. It can be made from al most any forage crop including perennial legumes and grasses, sorghums and small grains. Even crops such as sunflowers, soy beans and peanut and pea vines have been ensiled successfully. But com is the leading crop used for silage. And based on all of the knowledge we have, when the land and climate are suited for com, whole plant com silage pro duces more digestible energy per acre than any other feed crop. What makes com such a big hit for silage? Here are just a few rea sons: • Ensiling the entire com plant increases the amount of energy per acre from 40 to 50% compared to harvesting only the grain. • Com is high in sugar and starch which makes it relatively easy to preserve by ensiling. • It’s a relatively high energy feed, and while it is low in protein, it’s an excellent complement for high protein but lower energy al falfa and other legume forages. • Com silage production, har vesting, storage and feeding can be highly mechanized and because of its good ensiling characteristics it can be stored in a variety of structures with relatively low loss es when properly harvested and processed. Silo filling starts in late spring with winter grains. It gets a big boost in mid to late May with first cutting of alfalfa and alfalfa-grass mixtures. It continues all summer with later cuttings of alfalfa, other legumes and grasses, oats, sum mer annuals and other crops in cluding sorghums. BUT silo filling is in full swing right now when one out of every three to four acres of com grown in Pennsylvania will be ensiled. HYBRIDS FOR SILAGE At this time of year there’s no need to spend much time talking about hybrids for silage. Suffice it to say that as com breeders and animal nutritionists take a closer look they now know that when it comes to nutritional value for live stock all com hybrids are not alike. And it’s true that several re search studies suggest that the feed value or quality of whole plant com silage may not be as closely related to grain content as we have always assumed. Nevertheless until researchers can zero in closer on their findings we can still say with confidence that a hybrid well suited for grain production in your area will also be excellent for com silage. CULTURAL PRACTICES Now isn’t the time to go into detail on cultural practices for com grown for silage either. But we can, and should say that if com harvested for silage is to be a high quality forage in your livestock ra tion it must receive top manage ment during production, harvest ing and storage. For example, many studies have shown that increasing your plant populations improved both grain and forage yields with no change in silage quality. Thus, the' thumb rule that populations for silage in your area should be 2000 to 4000 plants per acre higher than for grain is still a good one. Also, we know the importance of a "balanced” soil fertility pro gram for top production. But fer tilization can also affect the fer mentation process. In fact, recent Wisconsin studies indicate that even greater attention must be paid to nutrient balance when crops are to be ensiled. MATURITY AT HARVEST Now is the time to talk about when to harvest your com crop for silage. Because stage of maturity or moisture at harvest time does have a significant influence on sil age yield and quality. I won’t go into all of the details, but based on neutral detergent fib er (NDF) and acid detergent fiber (ADF) values, as well as whole plant yields, for best quality silage stored in conventional silos har vesting when com is 62 - 68% moisture is a good choice. It should be slightly higher when stored in horizontal silos and slightly lower for limited oxygen silos. This stage, approximately full dent, say Penn State workers, is reached at a minimum of 40 to 50 days after com has silked. The kernel milk line should be near 50%, and the kernel black layer will not have formed. Frequently when com reaches physiological maturity total dry matter content is too high, proper fermentation may be a problem and feed quality may be sacrificed. LENGTH OF CHOP Now is also the time to talk about fineness of chop. And while researchers may not agree on de tails a good compromise on chop ping seems to be 3/8 to 3/4 inch theoretical length of cut for com harvested at the recommended stage of maturity. This will assure adequate packing and best use of silo space without sacrificing fi ber. If com is harvested at more mature stages, or when the whole g MAK.IT DOESABODY GOOD. MIDDLE ATLANTIC MILK MARKETING ASSOCIATION. INC plant contains more than 40% dry matter, a finer cut may be desir able. And don’t ignore the other rules of good silage making. Fill your silo as rapidly as possible. Distri bute the ensiled material as uni formly as possible. And do what is necessary to insure a good pack and keep oxygen out to reduce mold damage and spoilage losses. Compared to most forages com is considered a natural silage crop. And researchers can’t agree on the value of silage additives for this crop. Nevertheless many now feel that treating com silage with a proven silage additive may be beneficial, especially if conditions at ensiling are less than ideal. SORGHUM FOR SILAGE Because of our enthusiasm for com as a silage crop, little is said about when to harvest forage sor ghums for silage. It’s generally true that under the best growing conditions the yield of feed nutri ents per acre of forage sorghum is only 90 to 95% that of com. And the feed value of sorghum silage is only 85% or so of that of com sil age. Still forage sorghums are known to be more drought tolerant than com. And growing forage sorghums on droughty soils may be preferable to com. If you are growing sorghums for silage this year and hope to maximize production and quality, harvesting at the soft to medium dough stage is your best bet. And follow the same silage-make rules for sorghum as you do for com.
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