Impact of Agronomic Management on Nutritive Value of Corn Silage. Dr. Dan Undersander University of Wisconsin

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1 Impact of Agronomic Management on Nutritive Value of Corn Silage Dr. Dan Undersander University of Wisconsin

2 Forage Quality of Corn Silage the largest effects on corn silage quality are: maturity at cutting, harvest practices, storage management But Agronomic Practices can make a difference!

3 4% fat corrected milk (lb/day) Effect of forage quality on 4% fat-corrected milk production at four concentrate levels % grain in ration 20% 37% 54% 40 Prebloom Early bloom Mid bloom Full bloom Alfalfa maturity stage From Kawas et al., 1989

4 Corn is different than other forages While quality of stems and leaves declines with increasing maturity, overall silage quality increases due to increased grain content NDFD and starch content of corn silage on various harvest dates at Arlington, WI.

5 Corn Silage Yield and Quality Changes during Development

6 Corn Silage Variation across Growing Environments

7 Environment Influences on Corn Silage Less than half of variation in corn silage digestible energy due to genetics (non-bmr). Traits like soft kernel, digestible starch, etc., will compensate for poor management. Have one shot to get corn silage right.

8 Agronomic Factors affecting Corn Plant population Silage Yield and quality Forage yield increases with increased plant population. Forage quality decreases with increased plant population above optimum. Optimum may be about 4,000 plants/ha above that for optimum grain yield. Plant populations for optimum may be increasing.

9 Silage yield (DM mt/ha) Relationship between corn silage yield and plant density 21,0 20,0 19,0 18,0 17,0 16,0 Average of six locations Cusicanqui and Lauer, , harvest plant density (number/ha)

10 Whole-plant NDF, NDFD, and NEL as affected by population Treatment NDF NDFD NEL %DM %NDF (Mcal/kg) Corn 46.6b 62.0c 1.15a Conv sorg 50.4a 65.1b 1.03b BMR sorg 50.3a 74.5a 1.02b LSD (.05) Low population Med population High population LSD (.05) NS NS NS

11 Agronomic Factors affecting Corn Silage Yield and quality Plant population Fertilization Soil fertility beyond that for optimum grain yield produces not significant change in forage quality Corn silage removes more nutrients than corn grain, especially K and S.

12 Agronomic Factors affecting Corn Plant population Fertilization Row Spacing Silage Yield and quality Row spacing did not affect forage NDFD or starch content. The small increase in stover yield due to narrower row spacing (40 cm) is balanced by a small increase in grain yield, so overall forage quality does not change

13 Increase (Decrease) of Narrow Rows (mt/ha) Corn Forage Yield Change For Narrower vs 76 cm Row Spacing in Wisconsin ARL SHEWO* 1997SPAWO* 1998ARL FON06* 1998SHE VAL06* 1999ARL FON VAL ARL06* 2001ARL06 N= 14 trials Increased in 4 trials Decreased in 1 trial Average = 0.29 mt/ha 2002ARL ARL06 Average*

14 Agronomic Factors affecting Corn Silage Yield and quality Plant population Fertilization Row Spacing Planting Date

15 Agronomic Factors affecting Corn Silage Plant population Fertilization Row Spacing Planting Date Yield and quality Delayed planting reduces yield Planting date has little effect on whole plant NDFD. Delayed planting dates tend to have lower starch content, milk per ton (quality) and milk per acre than earlier planting dates.

16 Agronomic Factors affecting Corn Silage Plant population Fertilization Row Spacing Planting Date Cutting height Yield and quality Raising cutter bar tends to increase Starch, crude protein and in vitro digestibility (30 hr) Raising cutter bar tends to decrease lactic acid and NDF.

17 Percent of maximum (%) Average response of three corn hybrids to cutting height 105 Yield Milk per Ton Milk per Acre cm 60 cm Cutting height

18 Effect of cutting height on Corn Silage Yield and Quality Plt Date Cut Height Yield NDF ADF CP (cm) (t/ha DM) % DM % DM % DM Medium Late

19 Effect of cutting height Milk 2006 University of Wisconsin Corn Silage Evaluation System Randy Shaver, Dept. of Dairy Science Joe Lauer, Dept. of Agronomy Jim Coors, Dept. of Agromomy Form Input Kernel Processed yes/no Optional Starch Digestibility Tests Lab Value Lab Value Patrick Hoffman, Dept. of Dairy Science Higher cutting height produced higher quality but yield was reduced to make uneconomical. Lab Value Lab Value Lab Value Lab or Book Value Lab or Book Value Field Measure Calculated from Regression, KPS, DSA, or IS-IV Calculated Calculated Starch Digestibility-1x % of Starch *Critical Data Entry* Required Inputs Calculated Outputs Liters milk Liters milk per metric ton per hectare Index Index Field ID Lab ID KPS % DSA % IS-IV % DM % CP % DM NDF % DM NDFD % NDF Starch % DM Ash % DM Fat % DM DM Yield tons/ha Early 15 cm L001 yes % m L002 yes % late cm yes % cm yes %

20 Grain yield 15.5% moisture/a) The Relationship Between Corn Grain and Silage Yield y = -1.94x x R 2 = 0.70 n = 253 Current hybrids produce grain yield equivalent or greater than that of 1972 levels, by 1.0 to 2.0 bushels of grain per ton of silage at 65% moisture Silage yield (T dry matter/a)

21 40 Starch content (%) RFQ vs w2fy_ta Plot 1 Regr Starch= (FY) (FY) 2 R 2 = 0.52 N = Forage yield (T/A)

22 70 NS NDF Digestibility (%) Forage yield (T/A)

23 Milk per Ton (lb/t DM) MT = (FY) (FY) 2 R 2 = 0.41 N = Forage yield (T/A)

24 TDN (%) TDN = (FY) (FY) 2 R 2 = 0.42 N = Forage yield (T/A)

25 Using Milk 2006 to Sort Corn Silage Hybrids High milk/ton means high quality (to right) High Milk/acre means high yield Upper right quadrant = high yield and high quality

26 How Should We Manage Grain v Silage Hybrid Types? Trait Grain Silage Plant population /ha 70,000-75,000 4,000 5,000 more Planting date Early Early to 7 d later Row spacing 3-5% more w/ narrow 7-9% more w/ narrow Soil fertility Optimum Optimum Pest resistance Important More important Cutting height Ear Yield v Quality Harvest timing Drying cost Sour v Moldy

27 Forage Quality of Corn Silage However, Agronomically Differences exist among corn hybrids for yield and quality. Plant population, row spacing and fertilization affect primarily yield with little effect on forage quality. Cutting height can improve forage quality but will result in yield loss. The largest effects on corn silage quality are: maturity at cutting, harvest practices, storage management

28 Take home Growing environment has the largest effect on corn silage quality. Agronomic management has large effect on yield and little on quality.

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