Comparative study on yield and economic benefits of rape under different planting and mulching patterns

To establish drought-resistant cultivation techniques of rape (Brassica napus) in dry mountainous lands of the West China, the characteristics, yield and economic benefits of rape under five mulching/planting treatments were investigated in an field experiment using conventional cultivation as the control. The treatments included furrow planting with plastic-film-covered ridges (FURP), flat planting with half plastic-film mulch (FLHP), flat planting with complete plastic-film mulch (FLOP), flat planting with wheat-straw mulch (FLW) and furrow planting with plastic-film-covered furrows/ridges (FUFRP). Result showed that FLOP, FUFRP, FURP and FLHP significantly increased rape plant height, stem diameter and length of main inflorescence. While FLOP and FUFRP promoted first branching of rape, FLHP, FURP and FLW inhibited it. The five mulching/planting treatments unduly affected secondary branching of rape. Whereas FUFRP, FLOP, FURP and FLHP increased pod number per plant; FURP, FLW and FLHP increased grain number per pod. There were notable negative effects of FUFRP, FLOP, FURP and FLW on the 1000-grain weight of rape. Actual yields of FUFRP, FLOP and FURP were 2 111.25 kg·hm^-2, 2 017.95 kg·hm^-2 and 1 934.70 kg·hm^-2, respectively representing an increase of 52.16%, 45.44% and 39.44% over conventional cultivation. Net economic benefits of FUFRP, FLOP and FURP were 1 985.85 Yuan·hm^-2、1 868.55 Yuan·hm^-2 and 1 495.20 Yuan·hm^-2 which were respectively 2.22, 2.03 and 1.43 times higher than those of conventional cultivation. Yields and economic benefits of FLHP and FLW were significantly lower than those of conventional cultivation. The study suggested that in dry mountainous lands of the West China, FUFRP, FLOP and FURP were suitable mulching and planting patterns for rape cultivation. In terms of yield and economic benefits, the outputs of these cultivation patterns were higher than those of the other patterns of cultivation.