Optimizing the utilization of whole plant corn silage and snaplage by selecting hybrids and maturities

Abstract

Paper 1: Seventeen corn hybrids were evaluated to examine agronomic characteristics that has influence on performance to make whole plant corn silage (WPCS) and snaplage. Hybrids were harvested at the target 35% of DM for WPCS, and ear corn were harvested with 65% of DM for snaplage. The descriptive statistics was used to characterize hybrids. Principal Component Analysis (PCA) was performed to identify traits associated with dry matter yield (DMY) for both type of silage. For WPCS, the DMY ranged from 22.4 to 32.2 ton/ha and on average the hybrids have 26.6 ton/ha. The stover yield ranged from 11.8 to 20.7 ton/ha, while kernel yield ranged from 9.50 to 12.9 ton/ha. The plant weight minimum, average and maximum were 0.32, 0.38 and 0.46, kg of DM, respectively. For snaplage, the ear corn DMY ranged to 12.1 to 20.9 ton/ha, and the average was 16.8 ton/ha. The minimum and maximum kernel proportion were 72.6 and 81.3%, respectively. The husk and cob proportions average were 11.7, and 11.9, respectively. According to PCA, plant weight and stover yield have great contribution to determine DMY in hybrids used by WPCS. The kernels yield and the ear length were the mains factors to determine the ear corn DMY for snaplage. Different agronomic characteristics determine DMY for WPCS and snaplage. Hybrids with great DMY of whole plant not necessarily are the best option to making snaplage. Paper 2: In the second study, five hybrids were harvested at three maturities to make snaplage. Hybrids were harvested at the target maturity levels of 600 g/kg of DM (M1), 650 g/kg of DM (M2), and 700 g/kg of DM (M3). Fresh ears were separated into kernels, husk, and cob. Whole ears were processed and ensiled (snaplage) for 90d. Measurements included dry matter (DM) yield, nutrient analysis, neutral detergent fiber digestibility (NDFD30h,), and in situ starch degradability (isSD) for ear components and snaplage. The experimental design was randomized complete blocks using a mixed repeated measures model. Data were analyzed using the MIXED procedure of SAS, followed by Student’s t-test at P ≤ 0.05. The DM concentrations at harvest were 591, 642, and 683 g/kg for M1, M2 and M3, respectively. The aNDF concentration of cob increased (771, 793, and 819 g/kg of DM) and the NDFD30h decreased (261, 244, and 209 g/kg of NDF) for M1, M2 and M3, respectively. The aNDF concentrations of husk were 819, 837, and 841 g/kg of DM, and the NDFD30h were 320, 257 and 246 g/kg of NDF for M1, M2, and M3, respectively. The greater lactic acid (5.90 g/kg of DM) and NH3-N concentrations (38.2 g/kg of N) were found at M1. The starch concentrations and isSD of snaplage were affected by hybrid and maturity level (P < 0.05). As maturity increased, the isSD decreased (783, 731, and 703 g/kg of starch for M1, M2 and M3, respectively). The NDFD30h of cob and husk and the starch degradability of kernels/snaplage declined from M1 to M3. Snaplage should be produced with 600 to 700 g/kg of DM. Harvesting at DM concentrations lower than 600 g/kg compromised starch concentration; but DM concentrations greater than 700 g/kg impaired starch degradability due to restriction in fermentation.