Page 20—Corn Talk, Lancaster Farming, Saturday, February 13,1993 Greg W. Roth Department of Agronomy Penn State Much has been happening in the area of com production research at Penn State and some of our neighboring institutions. The purpose of this paper is to provide a brief overview of some of the results of this research that you may find use ful in your operation. This overview will focus on cultural practices and hybrid selection. The research areas that will be discussed will include silage yield and quality studies, com/sorghum compar isons, tropical hybrid evalua tion, plant population research, row cleaning devices, effect of cultural practices on root worms, stability analyses, and com maturity studies. Silage Yield And Quality For the past three years, we have been evaluating effect of hybrids, plant populations, and harvest date on silage yield and quality. Our hybrid studies have focused on determining whether or not some widely grown hybrids vary in silage quality as much as some reports have indicated in the literature. Also, we wanted to evaluate how consistent these differ ences were over a wide range of locations, because com silage is produced under a wide range of conditions in Pennsylvania, unlike some other areas. We used nine hybrids and grew them in four different tests in 1990 and 1991. We found that hybrids did vary for quality, but not that much. Variations in digestibility and pro tein were greatest. Digestibility differ ences ranged up to 1.8 percent and protein differences ranged up to 0.5 percent. The variation in ADF and NDF was not signific ant between hybrids when averaged over locations. On a per centage basis, yield varied much more than quality. We con clude that yield differ ences are most impor tant and should con centrate on belter testing for silage yield. Quality differ ences exist, but there appears to be some uncertainly about what to measure. Our data suggests that digestibility measure ments may discrimi nate between hybrids better than traditional quality measurements like ADF and NDF. Penn State’s Corn Research Results Comparisons of different populations and harvest dates have indicated that silage were maximized near populations of 25,000 plants per acre with population having little effect on quality. Ourharvest date stu dies have shown that for harvesting for silage in the 63-68 percent moisture range, harvest should occur between full dent and half milk in the kernel. We have found that maximum yields are obtained near half milk. Waiting to harvest silage until black layer results in silage that is too dry and increases the risk of molds in the silage. Corn/Sorghuin Comparisons We have been evaluating grain and forage sorghums as potential replacements for com in areas with drought stress potential and deer damage potential. To date we have con ducted five side-by-side com parisons. The sorghums are more drought tolerant and also resist damage from deer. In three of the strip trials, the deer ate the com right to the ground. In two others, the dam age to the com was more typi cal with most of the ears removed. Results of a typical trial are shown in Table 1. Table 1. Performance of forage sorghum, grain sorghum and three com varieties grown under moderately heavy deer pressure in Centre County in 1991. In grain bodies , aluminum makes Sense . < /; l! i?/ Eby’s time-tested design is available in lengths to 24’ and a 48” standard height; optional heights include 54”, 60” and 72”. A long list of standard features such as tie rail, built-in steps, aerody namic uprights and Harsh hoist is complemented M.H. Eby, Inc. I 1194 Mam Street (Route 23) 4435 State Route 29 \ BfflF U ■ Blue Ball, PA 17506 West Jefferson, OH 43162 (717)354-4971 (800)292-4752 FAX'(7I7) 355-2114 (614)879-6901 (800)752-0507 FAX: (614) 879-6904 I (O®IM fALE MIWS PENNSYLVANIA MASTER CORN GROWERS ASSOC., INC. Species/variety 19CYield Moisture ADF Forage sorghum, Pioneer 947 Grain sorghum, Pioneer 8333 Com/Doebler’s 45 X Com/Cargill SX 269 Com/Doebler’s 75X Based on the results of these trials, I conclude that forage sorghum is a good alternative under these situations. Early, medium height forage sorg hums that set a lot of grain appear to be a good choice for many of these situations. They resist deer damage even better than the grain sorghums, have low risk of lodging, produce good silage yields of reasonab ly good quality, mature before frost reducing the risk of prussic acid and give the grow er the option to harvest for grain. Tropical Hybrid Evaluations Interest in the success of using these hybrids as double crop alternatives in the South. There, agronomists have found that some tropical hybrids do exceptionally well when planted late, when normal com is often devastated by fall armyworm. Locally, some growers have been attracted to T/A % 11.01 61.8 35,1 64.6 6.28 78.5 25.4 72.3 4.65 42.9 36.5 61.3 4.71 65.2 37.5 60.6 5.30 68.3 33.0 63.7 these because of their height and seemingly large silage yield potential. In 1992 we compared the yield potential of a normal com hybrid, a tropical hybrid com and an open polli nated silage com in three grow ing environments. As expected Yield Harvest Yield Harvest Yield Harvest Com 21.0 9.16 14.9 a 10/20 19.7 a 10/5 19.5 ab 10/20 11.1 b 10/20 17.4 ab 10/12 17.7 a 9/29 14.0 b 10/12 Normal Tropical Open poll. Yields within a column fol lowed by the same letter are not significantly different.*Double crop com was planted July I.Plant population research Population research prog rams are currently under way at Cornell, Ohio State, and Wis consin. The Cornell program is far enough along so that recom mendations are being revised. They are suggesting plant populations up to 28,000 ppa where com is grown for grain by a full range of custom options, including tailgates, Wahpeton tarps and chute. When you select your next grain body, consider the value that aluminum offers. It’s a worry-free investment in your future. the tropical and the open polli nated were tall and late. The open pollinated was also prone to lodging, but the tropical hybrid stood well, even though it was twelve feet tall. The trop ical hybrid was susceptible to smut and had poor early season growth. Yields of both the open pollinated and the tropical were less than the normal silage com (Table 2). Based on the results of these experiments, tropical and open pollinated silage corns do not appear to be competitive with top performing conventional hybrid corns. Table 2. Yield and harvest date of a normal hybrid, tropical hybrid and open pollinated sil age variety in three environ ments in 1992 on good soils. They suggest up to 30,000 plants on good soils for silage. For less productive soils, plant populations should be reduced. In the Ohio State research, populations, N rates, and hybrids are being compared. There, com yields respond only when moisture was adequate and the full recommendation of N was applied. This occurred in one of three studies. A recent Univ. of Wisconsin study com- (Turn to Page 21) Eby Aluminum Grain Bodies pay off in dependable long-term service. Their all aluminum construction means: • Greater payload efficiency • Maintenance-free service • Substantially higher resale value. If you think that steel is cheaper, think again. 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