Pre-harvest Factors Outline. Pre-harvest Factors Abiotic Stresses. Pre-harvest Factors Abiotic Stresses

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1 218 Virginia State Feed Association & Nutritional Management Cow College Outline Environmental and Agronomic Factors Affecting the Nutritional Quality of Corn Silage Virginia Tech Nutritional Management Cow College (February 15, 218; Roanoke, VA) Abiotic stresses Planting density Row spacing Gonzalo Ferreira, PhD Department of Dairy Science Virginia Tech Abiotic Stresses Abiotic Stresses Spring and summer drought of 212 will be remembered as one of the worst agricultural calamities in the US (USDA, 213) Drought of 212 reduced the national corn grain and silage yields by 162 and 163%, respectively (USDA, 213) US Drought Monitor (8/21/12) Abiotic Stresses Corn Silage Hybrid Tests 212 Southern Piedmont Shenandoah Valley Hybrid ton DM/acre ton DM/acre A B 21 8 C 2 77 D E F 2 42 G H 2 3 Average 2 56 Behl et al (212) Virginia Cooperative Extension 1

2 218 Virginia State Feed Association & Nutritional Management Cow College Corn Silage Hybrid Tests 212 Abiotic Stresses Inches Precipitations from planting to harvesting Nutritional Quality 28% DM 116% CP 6% NDF ph = Southern Piedmont Shenandoah Valley Kernel Development Photo from Dry Matter, mg/grain Lag Phase Linear Phase The first 1 to 12 days after pollination (lag phase) are critical for kernel development Photo from Walbot and Evans (23) Nature Reviews Days After Pollination 2

3 218 Virginia State Feed Association & Nutritional Management Cow College Kernel Development Kernel Development The first 1-12 days after pollination (lag phase) are critical for kernel development The capacity of the endosperm to accumulate dry matter is established More endosperm cells imply more amyloplasts More amyloplasts imply more starch Dry Matter, mg/grain Effect of heat on grain DM accumulation % C 35 C Hanft and Jones (1986) Plant Physiology Kernel Development AX 882 Planting Date: 9/23/11 NK 94 RR2 Planting Date: 9/28/11 Cheikhand Jones (1994) Plant Physiology Growing-degree Days (GDD) Date T Max T Min Formula GDD Cum GDD May (85+62)/ May (86+64)/ May (85+61)/ May (86+65)/ May (79+62)/ Jul (86+68)/ Jul (82+55)/ Jul (86+56)/ Jul (86+64)/ Jul (86+71)/ Maximum Temperature, C /2/11 AX 882 Planting: 9/23/11 Silking: 12/3/11 9/27/11 1/4/11 1/11/11 1/18/11 NK 94 Planting: 9/28/11 Silking: 12/11/11 1/25/11 11/1/11 11/8/11 11/15/11 11/22/11 11/29/11 12/6/11 12/13/11 12/2/11 12/27/11 14 KOT? Rains (red) o irrigation (black), mm Jul (86+67)/

4 218 Virginia State Feed Association & Nutritional Management Cow College Dry matter concentration of whole-plant corn for silage Hybrid Southern Piedmont Shenandoah Valley Rains 197 inches 9 inches 11 inches 13 inches A B C D E F G H Average Neutral detergent fiber (NDF) concentration of whole-plant corn for silage Hybrid Southern Piedmont Shenandoah Valley Rains 197 inches 9 inches 11 inches 13 inches A B C D E F G H Average Data from Behl et al (211) and Behl et al (212) Virginia Cooperative Extension Data from Behl et al (211) and Behl et al (212) Virginia Cooperative Extension Southern Piedmont 211 Shenandoah Valley 211 Ferreira et al (215) Maydica Ferreira et al (215) Maydica Southern Piedmont 212 Southern Piedmont 211 Ferreira et al (215) Maydica Ferreira et al (215) Maydica 4

5 218 Virginia State Feed Association & Nutritional Management Cow College Corn Silage Hybrid Tests Georgia 212 IRRIGATION Area of Control Area of Influence Area of No Control Blairsville Calhoun Griffin Tifton Planting date Apr 18 Apr 11 Apr 2 Mar 28 Harvesting date Aug 31 Aug 23 Aug 17 Jul 26 Growing period, days Rainfalls, mm Supplemental irrigation No Yes Yes Yes Dry matter yield, ton DM/ac Grain component, % Data from Coy et al (211) University of Georgia Blairsville 475% grain Calhoun 359% grain Ferreira et al (215) Maydica Ferreira et al (215) Maydica Griffin 5% grain Tifton 493% grain Ferreira et al (215) Maydica Ferreira et al (215) Maydica 5

6 218 Virginia State Feed Association & Nutritional Management Cow College In certain regions, dairy farmers should be concerned for high temperatures as much as for drought! On-farm Study Argentina University of Wisconsin Effect of plant density on yield and composition of whole-plant corn Plant Density, plants/acre 24,3 28,34 32,4 36,45 P < Plant Weight, g DM/plant DM Yield, ton DM/acre Neutral Detergent Fiber, % Starch, % Word Cloud Ferreira et al (214) Journal of Dairy Science Ferreira et al (214) Journal of Dairy Science 16,2 26,3 36,5 46,5 Plant density at harvest (plants/acre) Cusicanqui and Lauer (1999) Agronomy Journal Is There a Target? 28k? 33k 26k 6

7 On-farm Studies 7 fields from VA ü ü ü ü 22, 28, 34, 4, 22K 28K 34K 4K Ferreira and Teets (217) Prof Anim Sci On-farm Studies 7 fields from VA Southern SARE On-Farm Research Program Hypothesis Increasing corn plant population can increase the recycling of N and P through the soil-crop system Objectives Determine yield and nutritional quality of corn silage Determine the extraction of N and P by corn silage Monitor residual N and P in the soil Ferreira and Teets (217) Prof Anim Sci and P Extraction Plant DM Weight Planting Density and P Extraction DM Yield Planting Density P < 1 DM Yield a b c Yield, ton DM/acre Plant DM Weight, lb/plant 6 P < 1 DM Yield a 6 79 b 85 a 8% k 3 k 35 k 26 k 3 k 35 k 7

8 218 Virginia State Feed Association & Nutritional Management Cow College Row Spacing Row Spacing DM Yield NDF Digestibility % NDF Ton DM/acre DM Digestibility Ton DM/acre 9 8 DM Yield inches 76 inches 38 inches inches 38 inches inches 7 % DM inches 38 inches Cox and Cherney (1999) Agronomy Journal Cox et al (26) Agronomy Journal Summary Heat stress can affect nutritional quality as much as drought Corn planting density More yield with minimal (if any) changes in quality Narrow rows Marginal increases in milk yield Thanks! Marginal changes (if any) in quality 8