残膜对棉田耗水特性及干物质积累与分配的影响

采用大田微区控制性模拟试验,测定并比较了新疆覆膜滴灌棉田3种不同残膜含量(0、225、450 kg·hm~(-2))对棉花的耗水量、耗水模数、棵间蒸发量、水分利用效率、干物质积累分配及其与耗水相关性的影响。结果表明,试验条件下,与无残留处理相比,随着残膜量的增加,生育期总耗水量有降低趋势,C_(225)和C_(450)处理分别降低了25.60、33.74 mm,但差异未达显著性水平,其中苗期、蕾期耗水模数降低较为显著,说明残膜降低了作物的耗水量,明显抑制了生育前期的耗水需求。与此同时,残膜污染的加剧,增大了生育期平均棵间蒸发强度,两个生长季C_(225)和C_(450)处理的棵间蒸发强度显著比C_0处理高0.07、0.16 mm·d~(-1),降低了有效耗水所占比例;此外,残膜不利于干物质的快速积累和在生殖器官中的高效分配,C_(450)处理籽棉产量和水分利用效率较无残膜处理分别降低了8.7%和5.6%。

Effects of plastic film residue on water consumption characteristics and biomass accumulation and distribution in drip irrigation of cotton

The plot and field simulation experiments were undertaken to determine the effect of plastic film residues on water consumption, consumption modulus, evaporation, water use efficiency, biomass accumulation and distribution in a drip irrigated cotton field covered by plastic mulch during 2014-2015 in an arid region. Three treatments including plastic film residue amount of 0 kg·hm^-2, 225 kg·hm^-2 and 450 kg·hm^-2 were designed based on investigation of typical cotton field representing local present situation. The results showed that during the whole growing period, residue addition of 225 kg·hm^-2 and 450 kg·hm^-2 decreased the water consumption by 25.60 mm and 33.74 mm and increased mean evaporation intensity of growth period by 0.07 mm·d^-1 and 0.16 mm·d^-1 compared to no film treatment, respectively. Although, total crop water consumption was not significantly affected by plastic film residues between 225 kg·hm^-2 and 450 kg·hm^-2 treatments, but was significantly decreased compared to no film treatment, respectively. The consumption modulus decreased with increase in the residual amount of plastic film, especially, in seedling and bud stage. Meanwhile, increasing plastic film residue could decrease soil water use efficiency and biomass. In sum, water consumption, effective water consumption ratio and seed cotton yield could be described by residual plastic film, respectively. And the water consumption demand in the early stage of growth was significantly inhibited. This study could provide valuable information for well understanding effects of residual film in farmland. Further field and modelling studies are needed to extrapolate the findings to a wider range of crop and site conditions, and to develop threshold and early warning informations to assist researchers or farmers to better to reduce the risk of residual film.