Factors Affecting Maize Forage Quality Development in the Northeastern USA

Abstract

AbstractTopographical features in the northeastern USA result in temperature and soil water differences between locations of close proximity. Dairy producers frequently inquire how these differences affect forage quality of maize (Zea mays L.). Field experiments were established in 1990 and 1991 at two locations and two planting dates to evaluate temperature and soil water effects on neutral‐detergent fiber (NDF), lignin, and in vitro dry matter digestibility (IVDMD). Whole‐plant IVDMD at harvest (R5 stage) had correlation coefficients (r) of −0.61 with NDF and −0.63 with lignin concentration at silking. Also, IVDMD had r = −0.90, −0.72, and 0.75 with NDF, lignin, and grain content, respectively, at the R5 stage. Stover lignin concentration and grain content explained 83% of the variability in whole‐plant IVDMD at the R5 stage. In the dry 1991 growing season, IVDMD was higher and fiber components were lower than in the wetter 1990 season. Locations, which had average temperature differences of 3.5°C from the eighth‐leaf (V8) to R5 stage, did not affect forage quality in 1990, but the cool location in 1991 had somewhat higher IVDMD and lower fiber components than the warm location. Nevertheless, regression analysis indicated that temperature did not contribute significantly to IVDMD variability and contributed only a small portion to NDF variability at harvest. In contrast, a calculated water deficit index value explained 74%o f the variability in IVDMD at early grain‐fill and 61% at harvest. Clearly, maize forage quality in this study was associated more with soil water differences than with temperature differences.