Nitrogen fertilizing and pre-anthesis cutting stage improve dry matter production, protein content and botanical composition in meadows

Abstract

Meadows in highlands are an important source of feed for livestock especially when harvested as hay for the winter period. Hay production from meadows largely depends on water table and management practices. A study was conducted on meadows with different water table levels (L1: high, L2: medium, L3: deep) for investigating effects of nitrogen (N) fertilization (N0: 0, N75: 75, N150: 150, N225: 225 kg N ha−1) and cutting stage (CS1: pre-anthesis, CS2: anthesis, CS3: milk accumulation) on hay yield and botanical composition in 1997 and 1998. Dry matter (DM) production changed depending on water table levels among sites. DM production showed relatively small increases when cutting was delayed in L2 until cutting stage CS3. The DM production and crude protein (CP) yield increased in response to N application, and nitrogen use efficiency (NUE) was the same in L1 and L2, but decreased in L3. N application slightly increased the ratio of grasses to legumes at L2 and L3. N had no effect on grass to legume ratio in the L1 location and L1 was dominated by rushes and sedges. As cutting was delayed in L1 and L2, the proportion of grasses increased, but rushes and sedges decreased. Fertilization practices have definite influences on botanical composition and production on meadows. Therefore, we propose 150 kg ha−1 nitrogen for flooded meadows to prevent N runoff, and 225 kg ha−1 for dry meadow in highlands. Cutting should be at the pre-anthesis stage.