Mineral concentration of silage corn (Zea mays L.) as influenced by hybrid and plastic mulch.

摘要

The use of plastic mulch at planting has enhanced germination, hastened maturity, and increased yield and quality of corn (Zea mays L.) produced in the cool climate ecosystems of Newfoundland (NL), Canada. Information on the influence of plastic mulch on mineral concentration and their associative relationships is lacking. The objectives of this study were to determine the influence of plastic mulch on (i) the concentration of P, K, Ca, Mg, Cu, Zn, and ratios of Ca/P and K/(Ca+Mg), and (ii) the magnitude and relationship of correlation coefficients among mineral concentrations of four short-season silage corn hybrids planted under plastic mulch in the field in 2000, 2001 and 2002 at three sites near St. John's, NL. Corn hybrids were planted in late May of each year on a well drained clay loam of the Cochrane series (Orthic HumoFerric Podzol). The hybrids were Pioneer 39NO3, Dekalb DKC26-75, Hyland HLS014 and Pickseed ExSile, abbreviated as PI, DK, HL and EX, and having CHU ratings of 2100, 2200, 2300 and 2400, respectively. At planting, half of each plot was plastic covered (PC) and the other half was not covered (NC). The plots were harvested in early October when the kernel milk line was between 50 and 75%. There was no year effect for the measured variables. However, there were significant site x hybrid interaction effects for the concentrations for all six nutrients. Hybrid-to-hybrid differences were considerably inconsistent across sites. A site x plastic x hybrid interaction effects for several of the measured variables suggest that some hybrids performed better under plastic mulch depending on the site. For example, increases in P concentration for DK due to plastic mulch was 1.6 g kg-1 at Burnt Hills whereas at Cochrane Pond and Shalomar it was 0.5 and 0.1 g kg-1, respectively. The results suggest that utilization of plastic mulch at seeding can be a key management factor, creating a more favorable microclimate that affects root temperature and modifies the absorption and translocation of P, K, Ca, Mg and Zn by corn. In some cases (e.g., P vs. K), there was a stronger influence of plastic mulch on the direction and magnitude of the correlation coefficients among the minerals than the plastic mulch treatment. Due to the significant site effect the extent to which this conclusion can be extrapolated to other climatic zones would require further studies involving a broader range of environmental conditions than was used in this study..