Latvia is recognised as a marginal area for growing of maize (Zea mays L.), as years of high yielding can be broken by years with failures. The aim of this paper is to describe maize yield, dry matter (DM) content in fresh yield, and some other quality indicators in silage maize field trials at the Research and Study Farm “Vecauce” of the Latvia University of Agriculture (56° N), in relation to temperature and moisture conditions. The study was carried out for 15 years (1999–2013). In total, 217 maize hybrids, belonging mainly to the early-maturity group (FAO up to 220), were investigated. Meteorological conditions considerably differed, and, according to heat conditions, only 10 years were suitable for maize production. The mean fresh maize yield varied from 43.01 t ha−1 to 63.39 t ha−1 during the study period, which 1.8 to 2.9 times higher than the average statistical yield in Latvian farms in the respective years. The DM yield ranged between 8.77 t ha−1 (in 2004) and 20.05 t ha−1 (in 2013) and was significantly correlated with temperature in May and June. The study suggested that cold tolerance of hybrids during early development stages should be investigated in future. Fresh and DM yield of maize were significantly (p < 0.001) affected by hybrid and year as factors, as well as by their interaction. DM content in fresh yield was correlated with active temperature sum. Low precipitation was a yield-limiting factor during some years. Ear proportion in yield decreased when moisture stress occurred before and during silking.
