西南旱地油菜田土壤水分和作物光合特征对覆盖材料和垄沟比的响应

为了应对西南地区频发的季节性干旱,提高旱作农田水分利用效率和作物光能利用效率,设置大田试验,研究不同覆盖材料(普通白膜、普通黑膜、生物降解膜和不覆膜)和不同垄沟比(40 cm∶40 cm和40 cm∶80 cm)对土壤贮水量和油菜光合特性、荧光参数、叶绿素相对含量(SPAD)的影响。结果表明: 油菜生育期不同覆盖材料下的土壤贮水量为:普通黑膜垄作(BR)≈普通白膜垄作(WR)≈生物降解膜垄作(BDR)＞不覆膜垄作(NR)＞平作(FP);在同一覆盖材料下,垄沟比对土壤贮水量无显著影响。与平作相比,垄沟集雨处理的净光合速率、气孔导度、最大荧光、可变荧光、PSⅡ最大光化学量子产量、PSⅡ潜在活性、光化学猝灭系数和非光化学猝灭系数均有所提高;与平作相比,WR、BR、BDR和NR处理的SPAD值分别提高6.1%、8.6%、8.5%和3.6%,瞬时水分利用效率分别提高18.3%、11.4%、16.3%和10.4%。相比于平作,BR、WR和BDR处理可显著增加油菜产量,NR处理增产不显著,普通黑膜垄作+垄沟比40 cm∶40 cm处理的经济效益最高。可见,垄沟集雨种植可以改善西南旱地油菜田土壤水分,增强油菜叶片光合能力,提高油菜产量,增加农民收入。

Responses of soil moisture and photosynthetic characteristics to mulching materials and ridge-to-furrow ratios in rapeseed fields in southwest dryland of China

In order to deal with the frequent seasonal drought and improve water use efficiency and crop photosynthetic efficiency in drylands of southwest China, a field experiment was conducted to investigate the effects of different mulching materials (common white film, common black film, biodegradable film and no film) and ridge-to-furrow ratios (40 cm:40 cm and 40 cm:80 cm) on soil water storage, as well as photosynthetic characteristics, fluorescence parameters and chlorophyll relative content (SPAD) of rapeseed, with the flat planting as the control. The results showed that the average soil water storage under different mulching materials followed the order: ridge with common black film (BR) ≈ ridge with common white film (WR) ≈ ridge with biodegradable film (BDR) ＞ ridge with no film (NR) ＞ flat planting (FP). Meanwhile, ridge-to-furrow ratios did not affect soil water storage. The net photosynthetic rate, stomatal conductance and fluorescence para-meters (F_m, F_v, F_v/F_m, F_v/F_o, q_P and q_N) of rapeseed under ridge-furrow with film mulching was higher than those under flat planting. Compared with control, SPAD value was improved by 6.1%, 8.6%, 8.5% and 3.6% under WR, BR, BDR and NR, while instantaneous water use efficiency (IWUE) was increased by 18.3%, 11.4%, 16.3% and 10.4% under those treatments, respectively. Rapeseed yield under BR, WR and BDR was significantly higher than that in control, while NR did not increase yield. The treatment of ridge with common black film + 40 cm:40 cm as ridge-to-furrow ratio could gain the highest economic benefit. Ridge-furrow planting of rainfall harvesting could improve soil moisture, increase crop photosynthetic capacity, and raise yield and economic income in rapeseed fields in drylands of southwest China.