Grain and forage performances of winter wheat in a rape and wheat rotation system

To investigate the potential of winter wheat to provide grain and forage in a rape and winter wheat rotation system, various cutting treatments were conducted on winter wheat (Triticum aestivum) following either Brassica campestris (BW) or fallow (FW) in the rain-fed region of the Loess Plateau. Cutting treatments were winter mowing (Cut1), spring mowing (Cut2) or no mowing (Uncut). We measured water status in the wheat growing period, the yield and quality of mowed forage, and grain yield and its components at harvest time. The forage yields of winter wheat after winter mowing and spring mowing under BW rotation were higher than that under FW rotation, whereas forage nutritive values of winter wheat between these treatments had no significant difference. In the BW rotation, the forage yield after spring mowing was significantly higher than that after winter mowing. The forage after both winter mowing and spring mowing had high nutritional value with more than 20% crude protein content and more than 151% relative feed value (RFV), however, micronutrient level was relatively low which cannot meet the daily requirement of livestock. Compared with FW, the grain yield of winter wheat under BW rotation decreased, especially grain yield decreased by 20.9% after spring mowing which most come from that the reduction of the numbers of panicles per unit of area. In the BW rotation system, the grain yields after winter mowing and spring mowing were lower than that without mowing. Dual-purpose usage of winter wheat for grain and forage in a rape and wheat rotation system could provide high-quality forage production without significant reductions to grain yield. Spring is the most appropriate time to harvest winter wheat for forage under this system.