Abstract:

This research explored multiple cropping planting options when following wheat with mixed cropping of forage rape and oats in the Jilin area of northeast China. The experiment comprised two control treatments and 36 mixed-cropped treatments. The control treatments were forage rape sown alone at 15 kg·ha^-1 and oats sown alone at 220 kg·ha^-1. The mixed-cropped treatments were a factorial combination of forage rape and oats sown at 50%， 60%， 70%， 80%， 90% or 100% of control rates， designated A to F， respectively， for variation in sowing rate of oats， and subscript 1 to 6， respectively， for variation in sowing rate of forage rape. There were three replicates making 108 plots in total. Samplings were conducted at bolting， full bloom， and pod-set growth stages to evaluate crop performance， and results were analyzed according to Grey System theory. It was found that at bolting stage， the hay yield of the experimental crops ranged from 3999.89 kg DM·ha^-1 to 5367.28 kg DM·ha^-1， the crude protein content ranged from 10.16% to 13.99%， the content of neutral detergent fiber ranged from 49.88% to 64.51%， and the content of acid detergent fiber ranged from 36.88% to 41.52%. At full bloom stage， the hay yield of the experimental crops ranged from 5102.35 kg DM·ha^-1 to 6453.52 kg DM·ha^-1， the crude protein content ranged from 11.28% to 16.01%， the neutral detergent fiber content ranged from 57.99% to 69.37%， and the acid detergent fiber content ranged from 33.88% to 48.80%. At pod setting stage， the hay yield of the experimental crops ranged from 5737.16 kg DM·ha^-1 to 6988.16 kg DM·ha^-1， the crude protein content ranged from 9.25% to 13.12%， the content of neutral detergent fiber ranged from 57.10% to 68.88%， and the content of acid detergent fiber ranged from 32.99% to 41.01%. As determined by multivariate analysis， for earlier harvest， the C₁ treatment （forage rape 7.5 kg·ha^-1， oats 154 kg·ha^-1） was optimal and had forage yields of 5281.23 kg DM·ha^-1 and 6152.52 kg DM·ha^-1 at the bolting and full flowering growth stages， respectively； for later harvest the C₂ treatment （forage rape 9 kg·ha^-1， oats 154 kg·ha^-1） was the best and the forage yield was 6988.16 kg DM·ha^-1 at the pod-set growth stage.

Key words: forage rape, oat, mixed cropping